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Thread: Sniper Cutting off with HyperSpark install.

  1. #11


    I'll check alternator tomorrow. But what I mean is that the problem I'm getting is the Sniper cutting on & off very quickly (Flashes error on all sensors on handheld). And as I said before, now it's doing it so much I can barely start the engine sometimes. But I was saying it only happens when the engine is cranking and or running. If I turn the car on but don't start, the engine the Sniper will not have the problem no matter how long I sit there. If that makes any sense?

  2. #12
    Join Date
    Dec 2009


    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. #13


    OK, that makes sense. The engine running is what generates the EMI. Please tell us how you have the battery grounds? I don't mean the ground wire on the Sniper, but the main battery ground that you have with or without EFI. The massive amount of EMI is causing the ECU to reset itself, which is the stumble.

    Check out this short video. Is yours wired exactly like this?

  4. #14


    Great video. I'm not having any issues, but I'm going to redo some of my grounds based off that.

  5. #15


    Alright I tried running the engine first with the belt off the alternator today. No change. And next I tried disconnecting the alternator switched 12V wire and the alternator main power wire while still having the belt off and no change again. I also couldn't get the engine to run long enough to check the alternator for stray AC voltage. But since there was no change with the alternator belt off. I'd assume the alternator isn't causing the problem? And as for grounds, it's close to the video but not exact. I have the battery ground cable going to chassis frame bolt (the HyperSpark ground is connected to this bolt as well). Then a ground cable comes off of that bolt and goes to the engine cylinder head to ground the engine. Should I try having it all in a loop like in the video? What else can I try or test?

  6. #16


    Not sure what to say at this point other than take a back to basics approach. By that I mean look over every single wire from start to finish and do it exactly like the instructions. Can't remember if your Sniper power & ground are straight to the battery, but if not then move them there. Make sure the 12V switched wire for the Sniper is on a relay.

    As for the car grounds, you said are close, but not exact. I'd say make them exactly like the video. Here's a more detailed video that I found. It is well worth 14 minute of your time. I tried to take some shortcuts on my initial install and ended having to redo a lot of it. Do it like the guy in the video and you will be steps ahead:

    Make sure your crimps and solders are solid. If you get the wiring 100% like the instructions and still have issues you can start looking at other stuff. It can be strange stuff like the air cleaner you run causes interference, but before looking at stuff like that, get the basics down.

  7. #17


    Okay, I'll keep looking over the basics and update my grounding and see if I can get some success. I'll keep you guys updated, thank you!

  8. #18
    Join Date
    Oct 2017
    Los Angeles


    I would not run any of the on/off wires or trigger wires from the HEI run/crank wire. I have noticed some people have good luck with that, and others do not. I tried the HEI pink run/crank wire and had bad luck with it meaning that wire caused lots of EMI. I would run the three trigger wires directly to the ignition switch.

    Also, since you're running timing control is your HyperSpark distributor fully synced and checked with a timing light. I'm not sure if the Hall-Effect sensor has the same problem, but if a magnetic pickup is not setup correctly, it can cause to big of a spark jump and cause EMI which results in the car stalling, popping and eventually dying.

    I'd take a datalog with the car turned on, but not running and push the gas pedal a few times and then stop the datalog and check it. I know you said the Sniper will stay on, but without proof and I'm sure your right then we can narrow down the problems. If it comes back clean meaning no weird traces any where then most likely it's in your ignition system. What kind of spark plugs are you using?

  9. #19


    RPnova Yes the distributor is phased correctly and timing is dead on with the timing light. Ive also checked under the cap and there are no signs of arcing. Spark plugs are advance auto NGK plugs. They are gaped to factory spec on a 70s 302 (My engine is a 302 block but has been stroked to a 347) But the plugs worked great when i had the HEI distributor on the car. I also took 2 data logs for you guys, the first is #9 which is me starting the data log and then cranking the engine once, The sniper was cutting on and off so much that it would not even start. The next log #10 is me turning the car on and pressing and depressing the gas pedal a bunch of times (sometimes quick and sometimes slow).
    Attached Files Attached Files

  10. #20


    It is interesting even without the engine running you have a bunch of data points missing. Open the datalog, right click on the graph and select "Mark Data Points". That will put a dot on the graph for every data point so you can see where there are dots missing. To zoom click and hold on a point on the graph then drag right & release. That will give better visibility to the data points.

    In Sniper 10 the start is really bad. Then 31 seconds and 62 seconds look bad. If you watch that second video I posted the guy says, "Marking data points will make or break your wiring job."

    I went online and bought 4 gauge welding cable for my ground wires. Was only about $1/foot I believe. You can also buy it at a local welding supply store. Get your battery to ground cable in place and see if that helps.

    Is your battery in the trunk? Also, take a peak down the throttle body and make sure all injectors are firing.
    Last edited by gregs69rs; 04-25-2019 at 04:58 PM.

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