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Holley Sniper EFI: How To Verify Timing Control Sync and Rotor Phasing

Hey guys, it’s Eric at Prestige. We have the new Holley Sniper EFI system installed
on this small block Chevrolet. We’ve ran it in. It’s really done great. It’s an economical system, performance is
spot-on with a 750 carburetor. Everything is working great. One cool feature of this system is that it
will actually allow you to control ignition timing using the Sniper EFI system. Now, in order to do that there is a little
bit of setup that is involved. Holley provides you with great instructions
on how to install the distributor, and how to phase in the distributor with the ECU in
the Sniper system. There are a couple of points that we would
like to add on to that just to do some check and balances. First we are going to show you how to verify
that the targeted ignition timing in the ECU is actually what the engine is seeing, and
once we’ve done that, we are going to show you how to phase in your rotor with your distributor
cap. So stay tuned and we’ll show you exactly what
we’re talking about. At this point your distributor should be installed
per the instructions provided with the Sniper EFI kit. We are using a MSD distributor with magnetic
pickup and a MSD 6AL Capacitive Discharge box. Our mechanical advance has been locked out
and we have installed an adjustable rotor. The engine has been rotated to 15 degrees
before top dead center of the compression stroke for cylinder number one. We have placed a mark on the distributor housing
representing the location of the number one terminal on the distributor cap, and installed
the distributor so the rotor is lined up with the mark. Next, Holley instructs us to retard the adjustable
rotor 15 degrees, and then turn the distributor housing to line the rotor back up with our
mark representing the number one cap terminal. We lock the distributor housing down and reinstall
the distributor cap. Here is where Prestige Motorsports’ checks
and balances come into play. First, we want to verify that the ignition
timing that the ECU is targeting is actually what the engine is seeing. To do that, we navigate to the initial startup
screen on the handheld so we can monitor the targeted ignition timing. Start the engine and check the actual engine
timing to see if it matches the ECU target. You can see our target is 36, but the engine
is actually seeing 28. This is because it is almost impossible to
be exact when you are lining the distributor and rotor up on initial setup. To sync the engine with the ECU, rotate the
distributor housing to adjust engine timing until it matches the ECU target. When the handheld target and the actual ignition
timing match, they are in sync. The second balance is phasing the rotor with
the distributor cap. A second distributor cap is needed to complete
this step. Using your spare distributor cap drill a hole
in-line with the terminal used for cylinder number one. Next, draw a line on your adjustable rotor
in-line with the center of the rotor terminal. Install the cap and use a timing light to
watch the phasing at idle and full advance. The rotor should sweep evenly across the terminal. If it is offset to one side, remove the cap,
adjust the rotor, and check again. It may take a couple of shots to get the phasing
correct. Once you are satisfied with the rotor phasing,
re-install the original distributor cap. Alright, there it is guys. That’s exactly how you verify that your ECU
timing is matching what the actual engine is seeing. And then also that your rotor is in phase with
the distributor cap, because you don’t want it too far off and jumping spark to another
cylinder. So that’s it. Thank you for watching. We hope that you enjoy your new Holley EFI
system. If you have any questions about phasing in
your ignition timing or setting up the Sniper system, feel free to give us a call at 704-782-7170
or send us a message through our website at

8 thoughts on “Holley Sniper EFI: How To Verify Timing Control Sync and Rotor Phasing

  1. Thanks for the video. I have had my sniper for a week now and have contacted Holley and MSD for some clarifications with no real answers and this is the first video i have found.

  2. Thank you for being the first to show this highly anticipated product. A complete unboxing and install would be so helpful. Looking to get this unit for my 86 El Camino and have some concerns with fuel system, electric fans and you already answered the timing issue. Thank you for what you have done thus far but more videos will be greatly appreciated and helpful.

  3. Holly crap how did you come up with that! Thanx. Im considering a Holley Sniper install since I moved to 6500ft elevation. My Summit carb is pissing fuel all over my engine ( Im still working on adjustments). This is great info to know. Thank you

  4. I am looking at Holly Sniper & FiTech, What Distributor is best , I have 383 stoker Chevy with HDI now. I do Not want spark boxes under hood = CLEAN Show set up.

  5. I’d like to use the Holley Sniper EFI with my Chevy 383. What are the pros and cons of the Holley Dual Sync vs Holley Hyperspark distributors? Thank You

  6. After the rotor and cap instalation and initial set to 15, my timing on the balancer reads zero. Am i suposed to keep turning the distributor till it reads 15 again?

  7. I use the same distributor and rotor with a MSD Atomic EFI. While I snugged the phillips screw down, twice at high RPM the top of the rotor came loose and three the timing off. I am afraid to tighten more in fear of cracking it. Are there any other fixed 15 degree retarded clockwise rotors that can be issued in the MSD ready to run distributor or even other 2 wire distributors so l don't have to risk this again? As for phasing the rotor, doesn't that throw off the timing you just set?

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