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Demystifying Holley Terminator and Sniper Ignition Hookup

Posted by Chris Myer 02/1/17 36 Comment(s) Sniper and Terminator X,

I recognize that the ignition control part of an EFI system can be the most intimidating part of the entire project.  And most EFI System manufacturers seem to focus more on "how to connect it" than "how it works", so even after some folks get it working they really don't know what they did.  The purpose of this article is to drill down just a little into the igntion wiring for the Holley Terminator / Terminator X and Holley Sniper EFI Systems, comparing these two it a bit more detail than I've seen done elsewhere.  If you can here just looking for tips on wiring the Terminator or Terminator X EFI ignition control, you can jump to that.

Sniper Ignition Wiring

The Sniper differs from the Terminator in that it has no EST/SPOUT signal--only a points output.  That is why it cannot control ignition timing using the the GM Small Cap HEI or Ford TFI ignition.  It can, however, be used to control the timing on a fixed-advance distributor provided that the rotor phasing is correctly advanced. Holley offers two *three methods, using either the new Holley HyperSpark Distributor, the Holley Dual-Sync Distributor or the other involving an MSD distributor with a rotor phasing kit   I will discuss those and then offer one more off-the-radar solution that some may want to try. What works best for you will depend on product availability for your application as well as your budget (not to mention your ability to deal with frustration.)

Sniper Ignition Control Using Holley HyperSpark Distributor & Ignition System (Preferred!)

*Updated June 2018: WIth the recent release of the Hyperspark distributor there is NO REASON that anyone should choose any other means of ignition timing control for their Sniper EFI System. The cost and ease of installation alone make this a no-brainer.

The HyperSpark operates with the Sniper EFI System identically to the Dual-Sync distributor (mentioned below) but costs 33% less and requires no adapter harness. Like any of the Sniper ignition timing control options it requires either a coil driver module or an ignition box but the next big plus in favor of the HyperSpark distributor is the availability of the HyperSpark Ignition Box and HyperSpark Coil. When installed together these three combine to make wiring this almost too easy. Three wires must be terminated but the rest of the system is plug-and-play with Metri Pack Connectors and two ring terminals for power and ground.

As for all of the stuff below about rotating the engine to 50 degrees before TDC and this and that to get the rotor phasing correct--HyperSpark Distributor installers get a pass. If you can manage to set the engine on top dead center (the "0" mark on the harmonic balancer) on the compression stroke then the hard work is done. The kit includes a rotor phasing cap that holds the rotor precisely where is must be relative to the base of the distributor. You simply drop the distributor in place, lock it down, and install spark plug wires.

The only challenge? At this writing only one application has been announced (for the Chevrolet Small/Big Block Engine, of course.) But I fully expect Holly to release a robust line of different applications before they call their work in this area complete. Here is a wiring diagram showing the installation of the complete HyperSpark ignition including the distributor and optinoally-available ignition box and coil:

Sniper EFI System Ignition Control with HyperSpark Distributor
Sniper Ignition Wiring with Holley Hyperspark Distributor and Ignition

Note that the your Sniper EFI System must be running Handheld firmware 1.1.7 or higher, ECU firmware 1.1.1 or higher to operate with the HyperSpark ignition. If you use the Sniper EFI Software to configure your HyperSpark ignition you must use version 1.1 Build 2 or higher. Once installed as shown above, the Sniper EFI System should be configured as follows,  This is done either using the setup wizard (if doing a new installation) or using the handheld tuning capabilities (navigate to Tuning > Advanced > Adv. Ignition for the Output Dwell and Tuning > System > Ignition Setup for the other three.)

  • Ignition Type: HyperSpark
  • Reference Angle: 57.5
  • Inductive Delay: 100.0 usec
  • Output Dwell: 2.0 msec

It's not mandatoryto use the HyperSpark ignition and coil with your HyperSpark distributor.  You can use any standard external coil and ignition box (or the Coil Driver Module included in the Sniper 4150 EFI System.)  Configuration is identical to that shown in the previous paragraph.  Below is an example of the wiring for an MSD 6AL.  Other capacitive ignition boxes will be wired similarly.

Sniper Ignition Wiring with Holley Hyperspark Distributor and MSD Box
Sniper Ignition Wiring with Holley Hyperspark Distributor and MSD Box

Sniper Ignition Control Using Holley Dual-Sync Distributor

If no HyperSpark Distributor is available for your application then I recommend performing Sniper timing control with the Holley Dual Sync Distributor.  No lock-out procedure or rotor phasing kit is necessary and the installation is greatly simplified via a adapter cable that connects the Holley EFI distributor's 10-pin connector to the Sniper 2-pin crank signal connector. Just like when using an MSD distributor with the Sniper, the included coil driver module or a CD box must be used. These two images show each without and with a CD box:

Sniper Ignition Wiring with Holley Distributor, without CD Box

Sniper Ignition Wiring with Holley Distributor, without CD Box

Sniper Ignition Wiring with Holley Distributor, with CD Box (MSD 6A Shown)

Sniper Ignition Wiring with Holley Distributor, with CD Box (MSD 6A Shown)

Here's a great video detailing the setup of the Holley Dual-Sync Distributor with the Shiper EFI System. If you follow these instructions you can set the ignition configuration as follows:

  • Ignition Type: Holley Dual Sync
  • Reference Angle: 50.0
  • Inductive Delay: 100.0 usec
  • Output Dwell: 2.0 msec

Sniper Ignition Control Using MSD Distributor

I do not recommend Sniper ignition control using the MSD distributor if a Holley HyperSpark or Dual-Sync Distributor is available for your application. I highly recommend using the Holley dual-sync distributor instead. Yes, I know that many of you come into this relationship already having an suitable MSD distributor. I encourage you to carefully consider the costs.

Some customers are struggling with RFI problems that seem to be introduced by the magnetic pickup. This has nothing to do with MSD--it's just the nature of a magnetic pickup in a high-RFI environment. It works flawlessly triggering a battle-hardened ignition system but when connected to more sensitive electronics it leaves the potential for issues. The Holley DSD, on the other hand, uses a hall effect pickup which simply doesn't struggle with the same issues as a magnetic pickup. Plus the Holley DSD is much easier to set up in the first place.

That stated, an MSD distributor can be used to perform ECU-controlled timing with the Sniper ECU. Both mechanical and vacuum advance must be locked out and a rotor phasing kit must be installed and adjusted accurately.  With the advance locked out, the rotor phasing kit allows you to manually set the position of the rotor to the correct location.  This can be done with or without a capacitive discharge box.  Just like when using the points output with the Terminator, a coil driver module must be used between the ECU Points output and the COIL (-) if a CD box is not used.

If you choose the MSD distributor route for doing Sniper ECU-controlled, timing, I do have some suggestions. Using the Sniper software, you can go to System Parameters > Engine Parameters and find the Ignition section. The ignition type should be correctly set to "Magnetic" but the Minimum System Voltage will be 0.00v and the Filtering will be Low. You will need to tune these values. Some have found that 0.65v is a more appropriate MSV, and some also prefer to increase the filtering on this to "High". Note that if you increase the MSV too high then it will have trouble detecting any signal when cranking.

If the above suggestions do not eliminiate the RF interference problem, another user I know went back to the original non-adjustable rotor. It sort of defies logic why this works but he claims it did the trick for him and I'm sure he's right. Be aware that this makes an already somewhat arduous process of setting the timing even more of a challenge as you have to now use the distributor position to compensate for spark angle at maximum torque.  I would absolutely consider this a last resort and only consider it if the paragraph above does not solve the problem.

These next two wiring diagrams show how to conduct ECU timing control with an MSD distributor both with and without a CD Box:

Sniper Ignition Wiring with MSD Distributor, without CD Box

Sniper Ignition Wiring with MSD Distributor, without CD Box

Sniper Ignition Wiring MSD Distributor with CD Box (MSD 6A Shown)
Sniper Ignition Wiring with MSD Distributor, With CD Box (MSD 6A Shown)

Watch this video for detailed instructions on how to setup an MSD Pro-Billet Distributor for use with the Sniper EFI System. If you follow these instructions then you will want to set your ignition settings as follows:

  • Ignition Type: Magnetic
  • Reference Angle: 45.0
  • Inductive Delay: 60.0 usec
  • Output Dwell: 2.0 msec

Sniper Ignition Control Using GM Large Cap HEI Distributor (Updated!)

There is one other method that has worked for some folks. That is to use a GM Large Cap HEI distributor. Compared to the first two methods this requires significantly more engineering, so proceed completely as your own risk. We know this does work, and it can save you a few hundred bucks, but I still believe that the large majority of folks out there are better served to use the Holley Dual-Sync Distributor.

This method requires that you get a GM Large Cap HEI distributor with the 4-pin module in it. GM offered these wtih 4-, 5-, and 7-pin modules. It is entirely likely that the 5- and 7- pin versions can be used as well but that is beyond the scope of this article. The 4-pin module has connectors labled B, C, W, and G. Attach them as follows:

  • Pin B: Leave Disconnected. This is the power for the module. You're not actually using the module, you are just picking up the signals you need at these points.
  • Pin C: Connect to the gray wire on the coil driver included with your Sniper EFI System.
  • Pin W: Connect to the purple wire (Crank +) on the 7-pin connector
  • Pin G: Connect to the green wire (Crank -) on the 7-pin connector

I have heard that sometimes it is necessary to reverse the purple and green wires on some distributors. Also, as implied above, you need to use the coil driver module. Connect the other wires as shown in the previous examples.

In addition to this, you need to lock out the mechanical and vacuum advance (as is done in the MSD method, above.) Rather than use some sort of rotor phasing kit, you just set the rotor phasing when you lock out the vacuum advance. As I said, this is a bit of a hack so that's part of the adventure.

Update:  Recently, Ian of TurboCamaro.CA created this AMAZING VIDEO of his success setting up the GM Large Cap HEI distributor to do Sniper EFI System ignition control.  This is a 30-minute video that is FULL of details.  It is on a 6-cylinder version of the large cap HEI but it should work as well for the 8-cylinder version.

NOTE: If you are struggling with making any of the ignition timing control methods above work, check out this handy ignition testing technique for point-output controlled systems.

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Terminator / Terminator X Ignition Wiring

Unlike the Sniper EFI System, the Terminator (HP / Dominator) and Terminator X ECU provides two ways to do ECU-controlled ignition timing:  Points Output (identical to the Sniper) as well as electronic spark timing /spark output timing (EST/SPOUT) signal. It should not be surprising that wiring the Terminator EFI Systems to control ignition timing using the Points Output signat is very similar to doing so on the Sniper.  Like with the Sniper, the white Points Output wire is used to ground the coil through either the Holley Coil Driver Module (PN 556-150) or a capacitive ignition box (like the HyperSpark or MSD 6EFI) and distributed using the Holley HyperSpark Disstributor or Holley Dual-Sync Distributor. 

Terminator Ignition Control Using Holley HyperSpark Distributor & Ignition System

Personally, I am a huge fan of the newly released HyperSpark ignition system.  Nothing beats it for plug-and-play simplicity.  We offer a harness (PN ESP TERM2HS) that reduces the number of manual terminations to only one--LESS required by the Sniper!  The HyperSpark ignition box does not offer a dedicated tach output signal but the Term2HS harness provides a tach output signal (blue wire.)  You can use that to drive the tachometer. Some factory OEM tachometers may additionally need a "tach signal amplifier" to function properly.HyperSpark Distributor to Terminator EFI System Wiring

Terminator Ignition Wiring with Holley HyperSpark Distributor

Here are the configuration settings you'll need to use when using the HyperSpark Distributor with your Terminator X (all software versions) or Terminator (using the Holley EFI version 5 or later software for the HP and Dominator ECU:)

  • Ignition Type: Sniper HyperSpark TBI / 1 pulse per fire
  • Ignition Reference Angle: 57.5 Degrees*
  • Cam Sensor: Not Used
  • Output Setup Type: Points Output
  • Output Setup Dwell Time: 2.0 msec

*There are two errors that must be noted for Terminator X users. First, if you run the setup wizard on the Terminator X handheld and select the HyperSpark as your ignition choice, it is going to set the reference angle at 50 degrees--not 57.5.  Of course, you'll catch that when you check your timing but if you don't realize that it is an incorrect IRA that caused this then you're going to adjust your distributor by 7.5 degrees and that is going to whack your rotor phasing.  Fix your IRA, not your distributor.  This problem persists at least through handheld firmware 1.0.8.

The second error is in the Terminator X software.  If you go there and look at the ignition reference angle you're going to see that it is at 15 degrees.  That is actually not the case.  The control is errantly limited at 15 degrees so that is what it displays for anything over 15 degrees.  Clearly, it is impossible to use this to set it at the correct angle of 57.5 degrees.  Ignore the 15 degrees here and simply use your handheld to change your reference angle to 57.5 degrees.  This problem persists through at least Terminator X software version V2.0 Build 50 and doesn't affect the standard HEFI HP/Dominator software used for the Terminator systems.

Here are the configuration settings you'll need to use when using the HyperSpark Distributor with your Terminator Ignition System using the Holley EFI version 4 software for the HP and Dominator ECU:

  • Ignition Type: Custom
  • Crank Sensor Type: 1 pulse/fire (Terminator V
  • Crank Sensor Sensor Type: Digital Rising
  • Crank Sensor Inductive Delay: 100.0 usec
  • Crank Sensor Ignition Reference Angle: 57.5 Degrees
  • Cam Sensor: Not Used
  • Output Setup Type: Points Output
  • Output Setup Dwell Time: 2.0 msec

Terminator Ignition Control Using Holley Dual-Sync Distributor

Terminator Ignition Wiring with Holley Dual-Sync Distributor

Terminator Ignition Wiring with Holley Dual Sync Distributor

Here are the configuration settings you'll need to use when using the Dual Sync Distributor with your Terminator Ignition System:

  • Ignition Type: Custom
  • Crank Sensor Type: 1 pulse/fire
  • Crank Sensor Sensor Type: Digital Falling
  • Crank Sensor Inductive Delay: 100.0 usec
  • Crank Sensor Ignition Reference Angle: 50 Degrees*
  • Cam Sensor Type: Single Pulse
  • Cam Sensor Sensor Type: Digital Falling
  • Output Setup Type: Points Output
  • Output Setup Dwell Time: 2.0 msec

*Assuming you install your distributor with the engine timing a 50 degrees BTDC on the compression stroke as suggested.

Terminator Ignition Control Using GM Small Cap HEI Distributor

The EST/SPOUT signal is the same as is found in many factory ECUs.  It is a +5V square wave trigger that is used to drive an HEI ignition module.  Because of that, it can be used to control timing on a GM Small Cap HEI or Ford TFI distributor.  This may work with other factory distributors that use an EST/SPOUT signal, but Holley only provides direct-fit adapter harnesses for these two at the time of this writing.  The distributor produces a points output that sinks the current from the coil, initiating the spark at the timing determined by the ECU.  

Terminator Ignition Wiring Without MSD Box

Terminator Ignition Wiring Without CD Box (GM Distributor Shown)

A couple notes about the diagram above.  Shown is the GM small cap HEI distributor installation.  See the Terminator instruction manual for Ford TFI example.  Signals A-K represent the 10-pin ignition connector on the Terminator main harness.  Note that while the adapter harness carries the cam signal from the distributor to the ignition connector on the Terminator main harness, Holley does not populate that pin with a wire back to the ECU.

If a capacitive discharge ignition box is used, then the points output generated by the electronically-controlled distributor will trigger the box to produce the spark ad the ECU-determined timing.

Terminator Ignition Wiring With MSD Box

Terminator Ignition Wiring with CD Box (MSD 6A Shown)

Handy Ignition Check Tip (Ignitions Triggered with White Points Output)

Recognize that whenever the white points wire is grounded the ignition should throw a spark. Knowing that, you can follow these steps to do a quick sanity check on your ignition.

  • Remove the coil wire at the distributor cap, insert a spark plug into the end and ground the spark plug securely to the engine..
  • Turn the key to the "On" position but do not start or crank.
  • Disconnect the 10-pin connector and momentarily ground the white points wire going to the ignition. Each time you do you should observe a spark on the cylinder identified above.


I hope that this article has helped to show that, once you understand some of the basics the different ignition configurations for the Holley Terminator and Sniper are not all that complicated.  I would love to hear your comments or questions, so please post them below.  I generally respond within one business day.

Click here to read more articles from Chris about the Sniper EFI System!

36 Comment(s)

Gary Tanner:
03/24/17, 07:33:42 PM

I may the only person in the world that followed Holley's suggestion to remove extra wires from 2 harnesses provided but now I find that I cannot go back. By that I mean originally I wired for a standard points system and since moved to a mag distributor and want the sniper to control timing. There is no information about color and placement that I can find. I have been on infinite hold trying to get the information and gave up. So I decided to post on the forum thinking that they would chime in but instead I got the usual 'call tech support'. Could you post a pic of both plugs showing color and location on the plugs. I would think it would useful information. Thx.

Chris Myer:
03/27/17, 07:03:41 PM

Glad to help! If you go to our Sniper Components Page you will find that we sell a 10-pin Metri-Pack Connector to allow folks to wire up their own custom I/O harnesses for their Sniper. Now, you already have a connector, but on that page are a picture of the connector as well as a list of the various signals and the pin letter into which they go. If you look very closely at the connector there should be a letter on each pin. Between that and the picture you should have everything you need to be successful. Good luck!

05/13/17, 01:41:12 PM,

I have the sniper controlling my timing, I have WOT set for 44deg, however when I go WOT the gauge shows timing "0" and when I let off timing is like 33 for cruze, but I never get the 44 at WOT only 0, I've tried other settings as well but WOT is always 0 wondering if anyone else had this issue?

Chris Myer:
05/16/17, 12:44:23 PM

Because I didn't have a clue on this I emailed Ken directly and got a few more details. it seems that the handheld wasn't just displaying '0', it was truly giving him zero timing advance at WOT (and, consequently, zero power!) Ken says he reloaded the setup a couple of times and the problem went away and everything runs great now. A bit odd. If you've had any experience with this please do add your comments!

06/6/17, 12:33:03 PM

#1 You stated that the Holley adapter harness 558-304 interfaces between the GM small cap HEI and the Terminator ignition plug on the main harness. But you stated that the camshaft signal doesn't go to the ECU from that point. So how does the ECU get that signal then? Is it needed to control the timing?

#2 Currently setting up the Terminator system on my old TBI GM and trying to figure out what ignition components I need to retain and what I can throw away. I have the main coil unit, a slave solenoid for the starter, and a 50 amp breaker that is wired to the slave solenoid and the starter. there are also a few relays that are wired in with these components. Do I need to keep these relays?

Chris Myer:
06/7/17, 04:27:34 PM

The cam signal is not at all beneficial in throttle body injection and is unnecessary for ignition control.

I'm afraid that I don't know enough about your specific setup to start suggesting what to start yanking. However, I will leave you with the advice an old friend gave me when I was building my first stock-class circle-track race car. I asked him what I should disconnect (as far as emissions controls, etc.) He said, "Just start yanking everything under the hood. When you finally yank something and the car won't start, put it back on. You're done."

You may or may not want to follow that advice. :-)

07/6/17, 10:10:20 AM

I need help. Just purchased Sniper. Hooked up to holley efi fuel tank system, all new Msd ignition. All wiring hooked up just like it is shown for no timing control. Set up wizard check. Crank signal and all gauges on LCD display function and read well. But no fire when cranking it over. Did not hook up yellow coil wire. And used supplied purple grey wire to tach put out off Msd box. Please help.

Chris Myer:
07/7/17, 11:48:19 AM

This gives me an opportunity to quote my Rule #1 for Troubleshooting EFI Engines: Avoid assuming that all problems are related to EFI. It is a very easy trap to fall into--but just as easy to recover from.

This is a good case in point. Nothing indicates a problem of the Sniper EFI system. You are receiving the crank signal and it is displaying RPM. And I suspect it will start just fine as soon as you resolve the problem in your non-EFI controlled ignition system.

Note too that all of the drawings in this post are for Sniper EFI-controlled ignition timing, so you can't follow these to wire your ignition. Page 14 of the Sniper EFI Instruction Manual shows that you use the included purple ignition adapter wire harness connected to the tach output on the CD box to connect to the purple/green pair coming off the 7-pin harness. If you have done that (as it seems you have) then the problem is in the new MSD ignition you installed. That is a bit outside the scope of this blog so I'd recommend you contact the vendor or MSD to get some assistance on resolving the problem. Good luck! :-)

07/9/17, 09:33:53 PM

Thank you for that description.. It answered a little about how the system is designed to work. I'm still confused on one thing you said.. "Any of the Holley EFI Systems can be operated with or without the ECU controlling the ignition. Which means if you like your existing ignition system you can keep it.".. It was my impression that the only time you could retain the stock ignition is if it were from an non-EFI car that didn't rely on the same sensors used by the Sniper ECU.I am putting my sniper on a 1999 4.6L 2v Ford engine- that has been converted from factory EFI to Sniper EFI for aesthetic reasons. Can I use the existing stock ECU to control the ignition via coil packs and use the sniper just to control the fuel side- and in doing this would I still retain the OBD-II functionality- or would all the inputs being robbed from the stock ECU and sent to the sniper mess up the stock ECU making it throw codes all the time?Jeremy

Chris Myer:
07/14/17, 04:36:24 PM

Ah, you are right--my comment comes with an unstated condition. I should have stated that is provided you have a stand-alone ignition (as is the case on most carbureted engines.) For those like yourself who might install the Sniper EFI System on an engine with an existing ECU-controlled ignition you are either going to have to figure a way to keep the stock ignition working (quite possibly doable, though I don't have the experience to confirm this) or else you'll have to retrograde to a stand-alone ignition.

Gary Bledsoe:
07/11/17, 02:49:45 PM

I'm putting together my motor now. It's a Oldsmobile 455 with roller cam/rockers. Will be using an Edelbrock Performer dual-plane intake (2151). In the next few weeks will be buying a Holley Terminator EFI (550-406) and a Holley Dual-Sync distributor (565-106). Can I purchase a coil driver module instead of a separate CD (MSD 6A) box to signal the coil?Note: This will be the initial startup of this motor.Thanks in advance,-GaryB

Chris Myer:
07/14/17, 04:45:44 PM

Good news! Holley made the decision up-front to simplify this decision by including the coil driver module in every Sniper EFI Kit. So you can go with either the MSD Box or just use the included coil driver, as you prefer!

I would go on to say that I don't usually recommend doing both the fuel and ignition setup at once on the Sniper EFI System. If you don't have any choice then don't worry, it is doable. The challenge is that if you run into any issues you have to really be on your troubleshooting A-Game. On the other hand, if you have any basic distributor-based ignition system that you can use to get the car running then that usually simplifies things a good bit. Either way, if you buy it here I'll be eager to help you every step of the way.

matt lane:
08/21/17, 01:46:25 AM

I was under the understanding that with the Terminator system you do not need anything but a Dual Sync unit and a good coil and that's it?!?!?

Chris Myer:
08/21/17, 02:37:49 PM

I hope that nothing I said gave that impression--My apologies if so! As explained in the Terminator Ignition Wiring section above, the points output required for ECU-controlled ignition timing comes directly from the Terminator ECU. Since the ECU cannot sink the high current blasts that would come from the coil on every spark an interface is required.. When wired up with the MSD box, the MSD box takes that responsibility. In the absence of the MSD box, that's what the coil driver module does.

Jesper Andersen:
07/12/17, 01:03:44 PM

I would like to use timing control function on my Sniper efi. But Im not sure how to connect the crank signal wiring ( purple and green wires ) to my Msd distributor. The Holley instruction only shows two wires from the distrubitor and there are no tags on them, only colors that dosn't match my distributor. The attached picture showes the wiring as it is on my car now.

Hope you can guide me. Thank you.

Jesper Andersen / From Denmark

Chris Myer:
07/14/17, 05:00:03 PM

I think I see the problem, Jesper. Yes, the MSD distributor is one of the two options for doing timing control on a Sniper EFI System but not all MSD distributors are included in that. The one you reference in your question appears to be what MSD calls a "ready-to-run" distributor--that is, a direct OE replacement. Unfortunately, the ready-to-run distributors will not work for this purpose.

The distributors that work are usually called the MSD Pro-Billet distributors. If you look at them you will see they have the same 2-wire connector that will mate to the green-purple harness on the Sniper EFI System.

It is my experience that you can buy the MSD Pro-Billet distributor for your application and add the required rotor rephasing kit and still be about $80 or so under what you would pay for the Holley DSD and adapter harness. But, it is also my experience that you might get into a situation where you'd gladly give that $80 away to resolve RFI interference issues, not to mention the additional challenge of locking out the advance on the MSD distributor. Use your best judgement and do what seems right for you. I'll provide my assistance either way you go.

08/18/17, 05:24:06 PM

New Sniper install with dual-sync distributor won't run. On my initial try, it ran for a few seconds and died. On subsequent attempts it started backfiring in all directions; out the exhaust, through the throttle body, and through the crank case, sending my PCV valve and breather cap into orbit. I attempted to set the static timing to 15 degrees, and that resulted in an instant backfire out the exhaust.

When I stop cranking, it will run for a second and just stumble out. If I try to give it some throttle, the stumbles and backfires persist.

I have followed and verified the installation and setup instructions for the dual-sync. Pulled #1 plug to verify I was on the compression stroke. Plug did not appear to be wet.

I have 3 pink wires (distributor adapter, coil driver and the pink from the 7-pin) going to 12v ignition, and a separate 12v ignition going to the coil. The gray wire from the coil driver is going to the (-) of an ACCEL DFI 75607 coil.

The white wire on the 10-pin goes to the white wire of the coil driver, black from coil driver is directly attached to the battery (-).
The main + and - are going directly to the battery posts.

The initial setup screen on the display checks out OK. When cranking it takes a second to sync with the distributor and an RPM signal is seen on the display.

I have a Walbro in-tank fuel pump with the recommended Holley fuel filter in place. The fuel feed is on the drivers side, the return is coming out of the regulated side of the throttle body unit.Any ideas?

Chris Myer:
08/18/17, 05:36:55 PM

Ok, so much going on here. First, a perfect example of why I always say, "Get your Sniper EFI System running with a non-ECU controlled ignition first." But I recognize this is not practical for everyone. Second--backfiring through the crankcase? I'm not sure how that happens unless you've blown a hole in the top of a piston. You might want to do some compression checks to make sure that's not the case.

Ok, trying to produce something of value here for you. Let's start by narrowing the focus. Backfires are not caused by the fueling system. This is a timing issue. If the engine ran previously then you can furhter narrow it to an ignition timing issue. Let's go forward with that assumption.You've not yet seen this new video from Holley. I am saying that with some certainty since it was only posted 2 hours ago (as I write this.) This is a fantastic video, even better that the video they had posted earlier. Have a look at this. In your case, pay special attention to the tips for confirming the wiring and syncronization that Tom provides at the 13:00 mark.

Hopefully this video provides you with some new ideas. Let me know how this works for you.

09/1/17, 02:55:33 AM

Regarding "Sniper Ignition Control Using GM Large Cap HEI Distributor", is there any reason I can't just remove the module and just hookup to the specified C/W/G wires? Or is there a benefit to having the module remain that I don't understand? I can find information about phasing a regular rotor, but nothing clear (diagrams or pictures) showing the wiring. I really don't want to get the Sniper and fry it with a "hack" like this, but I don't have $500 for an MSD distributor/rotor.

Chris Myer:
09/1/17, 05:18:45 PM

Pardon me for answering your good question with another question of my own. Are you really sure you need to do Sniper EFI-controlled ignition right now?

Here's the reason I'm asking. Doing Sniper EFI timing control with a magnetic reluctor pickup (as are found in the GM HEI) is filled with potential pitfalls, even when using the recommended MSD Pro-Billet distributor. So much so that we no longer recommend it (as is stated above.) To then add to the potential problems and challenges inherent to doing something completely different? Not a road I would take or recommend.

Further, if your existing ignition is working well, I would suggest that there is nothing that you will add by switching to Sniper EFI-controlled ignition timing that could possibly be worth the nightmare you are about to experience. Yes, there are some big benefits to Sniper EFI-controlled ignition timing. But not as big as the self-induced pain you are about to feel.

Instead, let me humbly recommend that you start setting aside the funds to get set up with a Holley Dual-Sync distributor for your application. Yes, that's even a few dollars more than the MSD route. But it is tried and proven to be a trouble-free installation. The MSD route in this case is also tried and proven--to be not worth the effort by most who make the considerable effort.

09/6/17, 03:23:53 AM

Thanks for the quick reply! Unfortunately my build isn't as cookie cutter as most. I've built up a 4.1L Chevy 250 with 8lbs boost and alcohol kicking in at 3lbs boost. I've just had total timing low but I'd like to have full control. Right now it has a 4 pin module and magnetic pickup in a large cap HEI. As far as I know, Holley isn't making a dual sync for my application.

MSD has the 8515 pro billet, which is nice but also over $550 (can) with the adjustable rotor and a coil. Perhaps I'm over simplifying it, but isn't the pro billet just a fancy gutted small cap HEI that's easily locked out? If that's the case, I can easily lock and wire my large cap HEI the way you suggested above. If it isn't phased, I'll adjust the vac advance lockout using a clear cap or cap with sight holes.

I guess I just don't understand the modified HEI method limitations or possible complications. Is it the pickup that's different? Any light you can shed on this would be great.

Chris Myer:
09/7/17, 06:36:32 PM

You, sadly, are correct, Holley doesn't make and likely won't make a DSD for your mighty 250. That being the case, there are a couple of very challenging keys to success. Personally, I would not only lock out the distributor but would gut the magnetic pickup entirely and install a hall-effect pickup but you're starting to run into a bit of money again. If you want to try to stick with the magnetic pickup then make sure the wires are tightly twisted and you might even consider shielding them. Then, be sure to adjust your minimum signal voltage and filtering as discussed above.

But, the bigger challenge is making sure that the rotor contact is at the spark tower during the duration of your advance curve. This confounds folks that even have the advantage of a phaseable rotor. Without it, you are really going to have your hands full. But it sounds like you are aware of the challenges and I think you have a shot at making it work. Good luck--you're going to need it! :-D

11/11/17, 02:17:34 AM

I brought a Terminator EFI setup for my 455 Buick is there any way i can use the ECU to control ignition timing.

Holley dont make a dual sync distributor for Buick that i can find. Any help would be much appreciated.

Chris Myer:
11/15/17, 04:20:28 PM

Absolutely! First, recognize that the Holley instruction manuals are greatly simplified, as is my article above, when it comes to the vast number of ignition options available in any given situation. This is necessary because if one tried to detail all of the different ways to implement the ignition on a given EFI system it would simply be more confusing than helpful.

The Terminator ignition options above use the SPOUT signal to trigger the ignition. Remember that the Terminator also has a points output just like the Sniper. That means that any ignition you can implement with the Sniper can also be implemented with the Termaintor.

Of course, at this point you bump up against the fact that we don't recommend using an MSD Pro-Billet distributor to implement timing control on the Sniper, though it is listed as an option. While getting the rotor phased correctely is still an issue with the Terminator it is not as sensitive to RFI as the Sniper ECU so that half of the problem goes away.

And remember that there are even more options. If you download the Holley EFI Wiring Manual you will find that you can implement a magnetic crank trigger (section 8.6) or hall effect crank trigger (section 8.8). If you use the Coil Near Plug Smart Coil Kit and the HP Smart Coil Harness to Holley EFI Main Harness Adapter then you can implement a coil-per-plug ignition on your Buick 455. The sky is the limit!

11/11/17, 08:43:26 AM

I have read a few places that it is possible to use a Ford TFI distributor by modifying the shutter wheel to have 8 equally sized shutters and adjusting the pickup location to match the input in crank trigger offset (i.e. 60 degrees) and wiring the three wires from the hall effect sensor the same as the dual sync (deleting the TFI module). Thus saving $400 with a little work and having a parts store availability for replacement parts. I was wondering how many people have successfully made this work?

Chris Myer:
11/15/17, 04:39:54 PM

At lease one has. Check this post over on the Holley EFI Forums.

Mick Webb:
05/29/18, 06:35:03 AM

Hi Chris , I have ignorantly purchased a Sniper for my project not realising that I have no distributor available to run it . I am in Australia and want to run a Australian Ford 4.0 Ltr in line 6 cyl that was factory EFI using a TFI . I want to run Sniper for simplicity and aesthetics . I managed to find an after market 4 barrel manifold to suit . Reading on your forum that Sniper can not control timing using a TFI Dizzy ,panic is slowly setting inn!

I just found this thread and looked at the link to Holley EFI forums , sounds simple enough but you don’t sound convinced. Please tell me if you think this will work as I can’t see any other options for my project to work.

Chris Myer:
06/2/18, 05:04:48 PM

First, lets be clear that you don't have to let the Sniper control the ignition timing for the Sniper to work. So if you were able to find an ignition system for your Ford 4.0 that would operate independently it would work fine with the Sniper EFI System.

Now, if you are relegated to using the TFI ignition that came with your factory EFI then you still might have a chance of it working, but it might require that you leave your factory ECU in place. The ECU should not care that there are no injectors firing but not having somethings like the throttle position sensor in place may create issues. There is only one way to find out: Try it! Leave absolutely as much in place as possible when installing the Sniper and see if you still get spark when you crank.

Hawk Phoenix:
11/30/17, 08:29:07 AM

Ignorant question of the day.....I have ordered a Sniper kit with the Master installation kit. I also have the Holley Dual Sync distributor ordered. As I'm reviewing installation instructions and watching videos, it appears that by removing my original distributor, (1980 Corvette, 350 SBC...pretty much stock)...that I am going to lose my coil. The Holley EFI kit includes a new coil control module, but comes the question.... Do I need to buy a new coil and what would you recommend? That's what it looks like right this moment....Thanks for your input!

Chris Myer:
12/6/17, 03:12:44 PM

Great question, actually, and one I get quite a bit. I like the MSD Blaster SS Coil with the Holley Dual-Sync Distributor. It packs a nice punch plus it's e-core design tends to resist breakdown and RFI much better than cannister-style coils.

12/3/17, 08:31:03 PM

I'm close to getting a Sniper for a '73 Dodge RV with a remanufactured 360 and the original Chysler electronic ignition. The plan is to take advantage of the available timing control using the existing ignition system, if possible. Can you steer me though this, or let me know if it's even possible?Thanks!

Chris Myer:
12/6/17, 03:19:12 PM

Installing the Sniper EFI System on your RV is a great plan. I expect that you're going to find both increased performance and economy (which are both generally in short supply in RV's!)

However, I think you're in for an exercise in frustration if you try to use your existing ignition to do EFI-controlled ignition timing (which will be critical to getting the performance and economy you seek.) While I am not that familiar with Chrysler ignitions, I am not aware of a way to easily adjust the rotor so that it is going to be indexed with the spark tower at the time of the spark. As mentioned above, even those who have the MSD distributor and the available rotor phasing kit have enough problems that I simply no longer recommend it for most.

Let me be careful not to imply that ECU-controlled ignition timing with your existing ignition is not possible. When it comes to ignitions there are so very many different things that can be done that it is entirely likely that there is a way to make this work. But two things I do know. First, I can't tell you how (so I'd be a blind guide.). Second I can tell you the great frustration that folks have had trying to make this work using factory ignitions.

Instead, I'd recommend that you go ahead and expand your budget to include the Holley Dual-Sync Distributor. There is a model available for the Chrysler 360. Along with this you will need a good coil (see the post above) and the Sniper-to-Dual-Sync Adapter. Installing this is much more of a slam dunk. I don't think of anyone that has failed in this effort. It is absolutely the route I'd suggest.

Charles Nix:
12/21/17, 10:46:40 AM, Efisystempro

Im trying to do my home work before i buy a replacement efi system for a worn out 95 gm TBI on a 454. Im looking a the Sniper system and it says you cannot use a small cap Gm Hei. Ignition question. Can I use the small cap Gm HEI if I pull the timing control module out of the distributor and just use the mag pickup already in it. It is prephased at 20 deg from the factory. Then use the it as the crank trigger and use the Holley coil input to drive the stock coil.

Chris Myer:
12/22/17, 12:24:46 PM

First, let me make clear that you can use the Sniper EFI System on your vehicle with nearly any ignition system setup--provided you aren't going to do Sniper-controlled ignition timing. I suspect you know that but I just wanted to make sure that was clear up front.

Beyond that, I have learned never to say "no way" when it comes to Sniper ECU timing-controlled ignition setups. Yes, certain very specific constraints need to be met. Yes, those constraints are met much more easily with some ignition setups (like the Holley Dual-Sync Distributor) than with others. But the basic bottom line is that you have to let the Sniper know precisely when the engine is passing TDC on the compression stroke _and_ ensure that the rotor is pointing to the appropriate spark tower at the time when the spark will occur. Beyond just accuracy in both of these requirements you must also ensure adequate signal strength and prevent the creation of RFI. That is where it gets a bit tricky.

How you do this is really irrelevant--which is why I avoid saying "that won't work." But, I have known some really bright guys who have failed to make this happen even when using the Holley-endorsed method of an MSD Pro-Billet Distributor and rotor phasing kit (which is why I don't endorse that.) So while I can cheer your ingenuity and sincerely hope the best for you, neither would I endorse using the small-cap hei distributor if you want your Sniper ECU to control ignition timing.

Since you're still in the homework phase, I would add that if you have an electronically-controlled transmission in your '95, that is going to be another challenge you will face. It can be done, but you will have to find a way to feed either the factory ECU or an aftermarket controller with the throttle position. Those who have tried to do this by splitting it off of the Sniper EFI TPS have not had good results. But adding a TPS is not too terribly difficult. Good luck! :-)

02/22/18, 12:58:21 AM,

I have a sniper and a msd pro billit E-curve distributor and I don't want the ecu to control timing my question for you is ...can I just hook up the yellow wire from harness to tach wire from distributor and call it a day ....

Chris Myer:
02/23/18, 02:46:29 PM

Absolutely! Regardless of what type if ignition you have, if it is working well for you before you install your Sniper EFI System it will continue to work well after the system is installed. The important thing to note is that if you're not doing ignition timing you only want to use the yellow wire to Coil (-) if you don't have a capacitive discharge box (like an MSD box.) If you do have an MSD box, don't use the yellow wire on Coil(-)--you'll damage your Sniper EFI System. Instead, use the included purple wire adapter and hook it to the tach output of the MSD box. (A separate brown wire is included that allows you to get your tach signal from the Sniper ECU if one is currently connected to the tach output on the MSD box.

02/22/18, 05:12:20 AM

I purchased the stealth unit and placed on brand new Dart SHP 427 and things have gone well enough but the perplexed part is timing. Used GM small Cap from DUI and have msd box. Timing is synced but system keeps making me second guess the sync. Set cruise timing at say 43 and when your actually cruising you'll see more like 33 on controller. While cruising if I watch close I'll see timing go to wot but tps is at say 55. I keep second guessing timing sync being right. Just don't seem right. My question is....if cruise timing set at 43 and your cruising at say 55 and tps is in the 20-30 range shouldnt you actually see cruise timing on controller at about 43 rather than 10-12 degrees lower than you set?

Chris Myer:
02/23/18, 07:01:26 PM

Here's the thing: The basic spark settings are intended to give owners a simple way to set the timing. But the reality is much more complex. While it is easy to determine when the engine is idle (that is primarily a function of throttle position), determining where cruise transitions to WOT is very engine-specific and has less to do with the specific throttle position than you might think.

You have to think of it in old school terms. The mechanical advance is merely a function of RPM. So that can be easily simulated. But the vacuum advance disappearing as you transition to WOT is determined by the manifold pressure. The manifold pressure cruising in a vehicle with a big engine with a mild camshaft (very low) is much different from that on a smaller engine with an aggressive camshaft (much higher.)

That being the case, the ECU has to sort of "guess" at what point the engine loses enough vacuum to be considered WOT (and thereby lose that additional advance.) If you feel that the resulting ignition timing is losing the vacuum advance portion too early, then you're going to have to go beyond using the basic spark setting and use the 2-dimensional table that is accessible via the software. The beauty of this is that you can theoretically use that table to nail down an absolutely amazing timing curve that could never be achieved with weights and vacuum. Of course, that often requires the services of an expert tuner with a dyno, but it is generally well worth the cost and effort.

03/1/18, 05:42:15 PM

I've got a sniper unit in my car and currently need a good distributor, as my old frankenstein is showing it's age again. I can't go the $500+ route of a Holley dual sync, but I'd like computer controlled timing. My question is- would it be possible to use an external coil, the coil driver and a GM style computer controlled distributor like the MSD "Street Fire EFI" #5591?

If so, what all would I need other than that? I feel like I am missing something here.

Anyways, my main goal is a smooth idle and a system that plays well with the Sniper. This is a heavy boy (69 Impala) that does not see high RPMs regularly, but does good burn outs when needed.

Chris Myer:
03/5/18, 09:41:19 AM

I have learned to never say never to ignition setups. Where there is a will (plus brilliant troubleshooting techniques and tons of patience) there is generally a way.

That said, it's unlikely that anyone is going to convince me that with the Sniper there is a better way to go than the dual-sync distributor. Don't get me wrong, I'm all about doing things in a cost effective way and am always looking for the best bang-for-your-buck. But, in this case, that best bang is the dual-sync distributor.

If you want to go another route then I think that my article, above, provides enough basic direction to get you on the right path. Some have done this well. Others, including some very bright mechanical minds, have spent countless hours trying to implement other solutions only to give up in frustration.

If you do go another route, I encourage you to come back here when you finish and let us know if you succeeded or if you burned through 100 hours of your life only to end up with a solution that "only occasionally stalls." If you put a priority on flawless engine operation, I'd go the dual-sync distributor route.

Roger Rowe:
04/9/18, 04:31:12 PM

Looking at installing a Holley Sniper EFI unit on my 67 Corvette and interested in timing control. Holley does not make a tach drive dual-sync distributor as far as I can tell. Would the Accel 77110 distributor be an option or should I just look at a MSD tach drive distributor? Thanks.

Chris Myer:
04/11/18, 03:55:12 PM

As I've said before on this post, I never say never when it comes to ignition setups. Where there is a will there is a way.

Some ways are much more painful than others, however.

The reason that Holley officially supports the MSD Pro-Billet Distributor as one of the approved methods of implementing ECU-controlled ignition timing is because MSD offers a phaseable rotor that works with most of these distributors. Accel does not have such a rotor so even more cumbersome methods must be undertaken to get the rotor phased correctly. (Cumbersome--not impossible. Never say never.)

I would not let your Sniper EFI Upgrade plans get put off track by the ignition issue, however. Keep in mind, the Sniper will work great with your existing ignition. In fact, as I always suggest, install the Sniper as a fuel injection-only system first, then upgrade to ECU-controlled ignition timing (if you choose to do so.) And, at that point, I'd still recommend the Dual-Sync distributor instead. I know there are devices that produce a mechanical tach driver from an electronic signal on the market. Others have replace the tachometer (Some even resorting to disassembly an aftermarket electronic tachometer and mounting it behind the factory gauge face plate.)

Jay Wilkins:
04/17/18, 02:22:18 AM

Hello Chris! I am researching installing the Sniper on my 1977 Jeep AMC 304. I currently have a CRT Performance large cap HEI billet distributor that works great. As per your suggestion I intend to initially get the sniper unit up and running without timing control. Then moving to the MSD distributor later to implement timing control.

For the CRT Performance distributor looking at the connections on this distributor I have a tach out and a power to the incap coil. My question is which wires from the sniper unit do I connect to these two connections? And, are there any other changes needed to the distributor?

Chris Myer:
04/17/18, 03:09:55 PM

Sounds like a good plan, Jay. Provided that you don't have a CD box (like an MSD 6) there is only one wire you need to connect at this point between the Sniper EFI System and the Distributor. Connect the yellow wire from the 7-pin harness to the tach out and you are done. If you have a tachometer that is already connected to that tach out signal, you need to disconnect it there at the distributor and then get your tach signal from the brown wire on the 10-pin hareness.

If you happen to have a CD box then don't use the yellow wire. Use the purple wire with the included extension wire) and connect that not to the distributor tach out but to the tach out on the CD box. Again, if there is a tach wire already using that signal, redirect it to the brown tach out from the Sniper.

Alvin Morava:
04/30/18, 12:17:32 AM

I am running a terminator stealth, and was running a pertronix dizzy, on a 351 cleveland that was originally points, had nothing but problems with dizz so bought a dual sync, no have no way to hook up coil, I do not want a msd box as I really dont have anywhere to put it, and trying to keep the classic clean look under the hood.

Chris Myer:
05/10/18, 05:35:27 PM

There is a great solution. Holley makes a coil driver module through which the Terminator ECU can drive the coil (-) without hurting the ECU output. You can find the coil driver module here. This is most commonly used with the Sniper EFI System but it works equally well with any ignition setup where you need to use the ECU's points output to drive the Coil(-) but don't want to use an MSD box to isolate the ECU from the coil.

Install the dual sync distributor just like Tom does in the first video at the bottom of this page. The dual-sync 10-pin connector will simply plug into the 10-pin ignition harness that is available on the universal (non-LS Specific) Terminator EFI systems. The Coil Driver Module has 4 wires. The white points output from the Terminator (found at position "H" of the 10-pin ignition connector) goes to the white wire, ground the black wire, and run switched 12 volts to the pink wire. The gray wire will be connected to Coil (-).

The coil driver module is very small an inconspicuous and can easily be hidden out of view. This should work well for you.

Shawn Doughtie:
06/17/18, 02:16:00 PM

I have a Terminator Stealth for my SBC, and while understanding the advantages of using the ECU to control timing, I was intending to stay with my Mallory Unilite & Hyfire (using the Hyfire tach output for the ECU) due to the former expense of the Dual Sync distributor. I noted the drop in price for the Dual Sync, but I'm even more interested in the HyperSpark. I see no need for the Dual Sync's cam position information for a TBI, so I'd like to go with the HyperSpark since the ECU can be triggered by its Hall Effect sensor. What wiring changes/connectors will I need to connect a HyperSpark to a Terminator Stealth ECU?

Chris Myer:
06/20/18, 05:38:31 PM

You are right--the HyperSpark is the hot new ticket for ECU-controlled ignition in the Holley EFI world. And it will work great with the Terminator EFI Throttle Body Injection System. As a result of your comment I've updated the post above to show exactly how this would work. Enjoy!.

Shawn Doughtie:
06/22/18, 06:23:17 PM

Thank you, Chris! Time to place an order with you for a HyperSpark!

Vince Gibbons:
09/30/18, 09:14:51 PM

I bought the sniper efi and installed it with my Mallory Unilite dist. Ran amazing. Then I decided to go all the way and bought the holley dual sync dist. I have had nothing but problems. Backfire through the tailpipe, through the intake, not cool. I have reinstalled it 3 different times, same result. I had a neighbour that is a mechanic do it after watching several holley videos, same result. I put the Mallory back in and it runs great. It is in an olds 400, my next move is to send it back to Holley to test. Do you have any thoughts.

Chris Myer:
10/5/18, 03:46:04 PM

Yes I do. It makes me wonder if you got the wrong clear cap. There are two--one for distributors that rotate Clockwise (Marked CW) and one for engines that rotate counter-clockwise (marked CCW.) I have seen Holley put the wrong clear cap in the box. Confirm that you have the right one for your Olds engine. If you do have the right cap then, yes, I think you need to send the unit back.

02/13/19, 08:54:35 PM

Long time listener, first time caller.

I'm planning on getting the Sniper EFI, Sniper Hyperspark distributor, and Sniper Hyperspark Coil. The only thing im not getting Sniper is the Ignition box since I already have one (MSD 6A). I was wondering if it would be difficult to wire all that together. I was told it wouldn't be a problem. I came here for advice if I should keep my MSD box or just fork out the money and get the whole hyperspark system. It seems pretty easy since it all connects together with plugs. Would it be much harder to wire all that up to the MSD? Thank you

Chris Myer:
03/4/19, 12:07:41 PM

One of the huge benefits of the HyperSpark system is the plug-and-play simplicity of installing an ignition system that already has all of the connectors designed to be mated together. However, if you already have an MSD box that is working and if you are handy at making wiring connections then it may be worth the money you would spend on the HyperSpark box to wire in your existing MSD box.

The only thing I'd point out is that MSD boxes don't last forever and it would be a bummer to do all of that wiring on an older MSD box only to have it croak a few hundred miles after you did all of that work.

Another thing I'd check is if your MSD box has the tach sweep feature and confirm that can be disabled. The tach sweep sends an RPM signal to the tachometer that pegs the needle at the current redline setting when power is initially applied. That must be disabled if used with the Sniper EFI System or else it floods the engine with fuel before you even engage the starter. Problem is as I understand it that there are a few older version of the MSD in which this feature cannot be disabled and therefore cannot be used with the Sniper EFI System. In that case you'd have to replace the box anyway. I'd sure want to know that before I did a custom wiring job on the old box, right?

Lance Hamilton:
04/14/19, 08:33:55 PM

Chris, I have a MSD Pro Billet 85551 distributor that is locked out and currently controlled by a MSD 6530 CDI box on a carb fed SBC. I want to convert the carb to a Terminator TBI and have the ECU control the timing. Your reply above is the first that I've seen in my research suggesting that I CAN use this distributor instead of adding a small cap HEI, dual sync or hyper spark distributor. I'd like to loose the 6530 just because I want to put the ECU where it is...but that doesn't have to happen if a CDI is required or suggested and it will work. Hope to hear back on suggestions for distributor, I'm very close to ordering the parts needed once I figure this part out.

Chris Myer:
04/14/19, 08:36:45 PM

Yes, Holley never published the idea of using the MSD Pro Billet distributors with the Terminator/HP/Dominator setups because other avenues were available (not to mention that pre-dated Holley's acquisition of MSD.) But when the Sniper was added and didn't have a way to do ignition control with either the GM Small-Cap HEI or Ford TFI ignitions, they obviously felt compelled to offer other options.

So yes, you can go the MSD Pro Billet route. And no, a CD box is not required, but if you don't use the CD box then you're faced with buying one of Holley's Coil Driver Modules, which is an investment that might leave you reconsidering leaving the box in place.

David Goodin:
05/4/19, 04:16:44 PM

Excellent article. I am installing the Sniper on my Chevy 5.7 liter engine in my boat now that the sniper is USCG approved. After reading your article I am purchasing the dual sync distributor. However, there is still one unanswered question I have.

The boat has a shift assist circuit that essentially “stumbles” the engine by keeping the negative coil I out grounded for every other firing pulse. This unloads the shift dogs in the outdrive and allows you to get out of gear.

Now the question; is the output of the coil driver module an “open collector” or in the case of a FET transistor “open drain”? If so, then the shift assist module will have no ill effect on the could driver.

One other question, could the could driver be used with the hyper spark distributer? Or does it require the use of the CDI and associated coil?

Chris Myer:
05/9/19, 12:32:49 PM

Intriguing question, David! Let me start with the easy answer--there is no direct benefit to purchasing the Dual-Sync over the HyperSpark distributor for the Sniper EFI System. There are some rare cases when I might make that recommendation but yours is not one of them. Go with the HyperSpark and save the cost difference for some other upgrade.

Now onto the question about the induced stumble. Though I will not commit to it, I am quite confident that the output of the coil driver module is open collector to protect it from the huge voltage spikes generated on the coil. But here is another issue: Those "misfires" generated by the stumble are going to be read as dead lean pulses, and the Sniper is going to respond by throwing fuel at it. A lot of fuel.

Here is the route I would take. Disconnect the shift assist circuitry from the ignition entirely. Instead, implement a 1-dimensional table (using the Sniper software) that retards the spark timing to some degree at which the air/fuel charge is already clear of the combustion chamber. Implement this with an external input, preferably using the existing shift assist circuitry. You can even specify that the closed loop and learn be disabled during this event.

Tanner marlett:
06/5/19, 09:59:04 PM

Recently installed a sniper kit with the hyper spark distributor. All I got was the distributor. No box or coil. Currently having issues with getting spark. Basically I’m not getting any. I wired the distributor into the ignition coil driver the way it said to but I’m still not getting spark. Truck ran fine before the swap. Any help would be greatly appreciated

Chris Myer:
06/13/19, 04:47:04 PM

The first thing to do, of course, is to use the "Handy Ignition Check Tip" at the end of the article above. If you are not getting spark then you have a problem in the ignition system, most likely with something not being powered or grounded correctly. Check switched power to your coil and coil driver module and ensure that both are grounded as well.

If you are getting spark then reconnect the 10-pin connector and crank the engine with the coil wire still disconnected from the distributor and the spark plug inserted and grounded. If you are not getting spark then there is a problem with your HyperSpark configuration in the Sniper EFI System. Ensure that your ignition type is Hyperspark, your ignition reference angle is 57.5, your inductive delay is approximately 100 microseconds (may need to be tweaked once running) and your output dwell is 2.0 msec. If all of this is true confirm that your HyperSpark is getting power. If that is the case then you're going to have to contact Holley Tech Support to have the system checked out.

If you reconnect the 10-pin connector (as described in the previous paragraph) crank and do get spark but it won't crank when the coil wire is replaced there may be some sort of timing issue or the plug wires are not in order. Usually this will produce some pretty nasty results (backfiring, kickback, etc.) However, I just spent HOURS helping a guy who was in this situation with his small block Chrysler 360 and although he's got spark the engine won't hit a lick. A complete mystery. This situation is literally being resolved as I write this so I'll have to post what happened later. :-)

Jay Fountaine:
11/29/19, 02:54:57 AM

Chris I have recently purchased a super sniper 4500 and I have a question about, how can I use my MSD 7AL-3 and have the sniper parameters control all aspects of my timing. All I can see is that if I use my 7AL-3 I have to select no timing control by the sniper. I might just be missing something? I am running twin turbos, progressive nitrous, trans brake, and running C16 fuel. Will be purchasing your level 2 plan to get help with a tune after I get this set up running. Thanks.

AJ Ramos:
12/3/19, 11:35:36 AM

You can certainly choose to continue to control the ignition timing using the MSD 7AL-3. Or you could use the 7AL-3 simply to provide capacitive discharge and protect your Sniper's points output from flyback voltage generated by the coil. But that turns your 7AL-3 into a rather expensive version of the HyperSpark ignition. If you want to let the Sniper control your ignition you might consider re-purposing that 7AL-3 on another project and going with the HyperSpark ignition box.

Jeff philips:
01/1/20, 05:02:18 AM

Hi was looking at distributor diagrams on gm small cap distributor if module removed can this be used on a sniper efi? With a sniper efi coil?

Chris Myer:
01/7/20, 05:05:33 PM

The Sniper EFI System simply doesn't have the SPOUT signal that is required to drive the HEI module on the GM Small-Cap distributor. It will work on a Terminator EFI System because that system does provide the required SPOUT signal but not on a Sniper EFI System.

Casey Wilson:
04/8/20, 11:49:17 PM

Way late to the original post, yet wondering: If using Sniper EFI, HyperSpark distributor, and Coil Module Driver into a relay, are you also using a relay for all those 12v clean switch sources? If so, also using a ballast resistor for that coil? If so, where in the wiring diagram?

Chris Myer:
04/9/20, 06:44:24 PM

I always recommend using battery-power via an ignition-switched relay for all of your sensitive electronics. On my truck I have a small 4-position mini fuse panel that is battery powered through a 30-amp relay. It provides switched power to the Sniper EFI System, the HyperSpark Ignition Box, the HyperSpark distributor, and my 4L60E transmission controller. A ballast resistor is used in the ignition systems of older cars and is not relevant to your upgraded HyperSpark ignition so you can leave it out.

Casey Wilson:
04/22/20, 04:06:28 PM

Chris, I appreciated your response. I feel like I have an issue with the pre-installed fuel relay from Holley. I've tested and isolated everything to this relay, and I just cannot get the fuel pump to run when using the pre-installed relay....almost as though it is wired incorrectly....yet I can jump from my battery-power source directly to that fuel line wire and get it to run. The wires APPEAR to be correctly wired into the relay (power to 30, blue fuel to 87, etc.), but the fuel pump doesn't run when I try to turn it over. Have you seen this or can you offer any suggestions? Again, I appreciate your time.

Chris Myer:
06/3/20, 05:04:33 PM

Have you replaced the relay? These can and do fail. If you can detect the thin blue wire going to ground at the point the fuel pump should be coming on, if the thin pink is hot, and if you can jump across from the heavy red wire to the heave blue wire and the fuel pump comes on, the relay is probably failed. Just pick one up locally and try it.

Michael Lindsey:
04/20/20, 01:14:04 AM

Chris, I’m currently running Sniper EFI with a small cap pro billet, digital 6AL and Blaster 2 coil on a 383 gen 1 SBC. I’m sure RFI can cause a broad range of issues but are there any problems that you hear about more than others? I’m all but certain that I have some serious RFI interference because the unit constantly resets (handheld shows red numbers,AFR says heating, etc). I have tried .30 -.65 on minimum signal voltage with no change. All of my power wires are connected directly to battery and routed away from plug/coil wires(accel ceramic 9001 I think). The block is grounded to battery on both sides with another 2 grounds to each cylinder head. The mag pickup and 6AL/Sniper switch wires are ran separately. The sniper ECU controls my fuel pump relay via the negative signal from the blue wire so it doesn’t matter if it’s intermittent, the motor immediately stalls because the fuel is shut off. Not sure if it matters but I have an AD244 alt (127A at idle-180A at 3800 rpm) and a SPAL PWM fan controller connected to a bus bar. I wish there was a pattern or specific environment as to when the unit resets, but sometimes it happens immediately and then there’s times where I might drive an hour before I get the dreaded stall. I would say it happens more often sitting still or at low speed but it’s made things interesting at highway speeds as well which in a car wouldn’t be terrible but the setup is in an 86 CJ7. Sorry for the long post but I have tried other tech support and cannot get through due to high call volume.

Chris Myer:
06/3/20, 04:54:37 PM

I absolutely would not even consider doing Sniper-controlled ignition timing with a an MSD Pro-Billet Distributor unless the EFI system first worked flawlessly without it. Is that the case? If so then that implies that any problems that are generated are a result of the implementation of the ProBillet as a source of both crank trigger and spark distribution. Either your operating environment is simply too noisy for the the magnetic pickup signal to be reliably detected by the Sniper, your crank phasing is not correct, or your rotor phasing is not correct. At this point you have to ask yourself: Is wrestling with this really worth the price of the HyperSpark distributor?

Michael Lindsey:
06/3/20, 09:18:01 PM

Chris, I just wanted to follow up in case another poor soul encounters the same or similar issues as I did. I have purchased a hyperspark distributor since my original post and did not have a single problem until a month later. I had not touched, programmed or made any changes what so ever in at least 2-3 weeks. What I found after several days of troubleshooting, was the sniper EFI main power fuse holder did not grip the fuse at all on one side. I then remembered I had moved the fuse holder when I installed the hyperspark distributor to make room for another unrelated accessory. I was able to recreate scenarios where the circuit was open, closed and even intermittent after pulling then reinserting the fuse. I had checked that circuit multiple times previously without any indication of a problem. I consider myself lucky but after a little squeeze, the issues disappeared and fingers crossed, hopefully will stay that way.

Chris Myer:
07/2/20, 04:46:08 PM

Thanks so much for sharing that!

08/2/20, 07:17:33 PM

My father and I have been trying to set up a Hyperspark distributor with a Terminator EFI, but we're running into a problem during setup on the handheld. No matter what we do there's no option for Hyperspark in the EFI handheld setup wizard.

Chris Myer:
09/29/20, 12:38:41 PM

Try updating the firmware on your handheld. It predates the release of the HyperSpark. Be sure to update your ECU firmware to match.

03/3/21, 11:10:20 PM

I have a BBC 496 Holley Terminator X Max Stealth, Hyperspark Distributor, Hyperspark ignition and coil. My PC software will absolutely not let me set an ignition reference angle greater than 15. I have The ignition parameter set to Hyperspark TBI / 1 pulse per fire and am attempting to set 57.5 per the instructions. Any clue why?

Chris Myer:
03/9/21, 06:55:16 PM

Yes, this is a bit bewildering. For some reason Holley decided when writing the Terminator X software that it would be better to reference the crank position at the point at which the distributor is installed rather than the crank position where the trigger passes the hall effect pickup. And had they made this decision from day one I'd say it's a great choice. But when you have one system that uses one method (Sniper, reference angle 57.5 degrees) and another that uses a second (Terminator X, 0 degrees) it is going to lead to some confusion. But now you know. :-)

03/17/21, 08:25:32 PM

Could you tell me the correct way to install a MSD pro billet to control timing. System was running great, so I've locked out mechanical and vac advance, followed the instructions on page 27 of the installation guide.Set crank to 15 degree, retard phasable cap to 15 degrees, drop it in, and perform timing checks. Done.The video, linked in the instructions, say to set at 45 crank, line up the reluctor wheel, and then adjust the rotor to No1, and adjust the software info.No idea as to why the instructions contradict each other.

Chris Myer:
03/20/21, 12:41:10 PM

Sadly, I have yet to see an instruction on how this is done that even begins to be adequate to the task of installing an MSD Pro-Billet Distributor to do timing advance with the Sniper EFI System. That, along with the fact that is has to be done precisely correct or it will be a miserable disaster, is why I generally don't recommend taking this route. But, while I'm not going to try to provide an adequate instruction here, I will hit the highlights.

1. Lockout the distributor advance (mechanical and vacuum.)

2. Rotate the engine to 50 degrees before TDC on the compression stroke.*

3. Install the distributor and turn the base so that the reluctor wheel is aligned with the pickup. Lcck it down

4. Rotate the engine to 30 degrees before TDC on the compression stroke.**

5. Using a phaseable rotor, align the rotor with the #1 spark tower.

*Why 50 degrees? Doesn't have to be but must be about 10 degrees higher than the highest advance you expect to run. If you're going to have 45 degrees of advance in your cruise range then you'd probably want 55 degrees. That's why HyperSpark uses 57.5.

**Why 30 degrees? Doesn't have to be. It should be precisely in the middle of your timing range. If you're cranking at 15 degrees and running 45 degrees in your cruise range then (45 + 15)/2 = 30. This minimizes the potential for arcing inside the cap.

Yes, I need to turn this into it's own instruction. One day. I still recommend using a HyperSpark distributor if one is available for your engine.

05/5/21, 08:05:48 PM

Chris, what should these values be for the Terminator X TBI used with the hyperspark?

Chris Myer:
05/6/21, 02:10:57 PM

I have updated the post above to include the settings for the Terminator X. Essentially it is the same as the Sniper but look for the selection called "Sniper HyperSpark TBI / 1 pulse per fire" in the System Parameters / Ignition Parameters of the Terminator X software.

Russell Jones:
11/17/21, 06:25:14 PM, none

My installation is a port injection with a Hyperspark unit and distributor. I'm trying to keep it simple and straightforward - just fire 8 plugs and 8 injectors, feed a tach, and trigger my fans. I had to buy an unterminated (and unlabeled) Holley EFI Main harness because the labeled harness is not available right now. Holley tech gave me this info to connect my unterminated harness to a Hyperspark box and distributor and feed/signal my tach.

The red wire in the distributor pigtail is switched-power-in, sourced from a 12V switched input. A distribution point for multiple switched 12v outputs/power supplies: the HP/EFI ecu, the Hyperspark box, and the Hyperspark distributor.

The green wire in the distributor pigtail goes to J1 A14 pin. In my harness/J1A connector it's a black wire in the connector but documented as green

The black wire in the distributor pigtail goes to the J1 A30 pin. Crank Speed input purple wire

Use the J1 A28 pin - blue white wire to drive a tach.

Hope this helps someone else...

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