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Thread: Buyers Remorse - Sniper EFI

  1. #1

    Default Buyers Remorse - Sniper EFI

    Today was the second time the Sniper EFI left me stranded for reasons that are beyond my ability to comprehend. I've only had the car running for 2-3 weeks and have driven it maybe a half dozen times.

    Today: Started fine, drove great. I was monitoring all the sensors on the way to the gas station. AFR was right where it was supposed to be. Filled her up with 93 octane and then problems. Was barely idling at 400 RPM, TPS was at 0% while the IAC was inexplicably at 30% for some reason. Died after 5-10 seconds of this. Tried to start it again and got the same result. Tried a third time and the handheld says "Searching For ECU..."!!! No ability to get any datalogs since anything I try to do on the handheld said "Read Error". You have got to be kidding me!

    I had to have the car towed home. I was under the impression that EFI would be a user-friendly reliability upgrade over a carburetor. This has not been my experience thus far. It's the seemingly random bouts of sketchy operation that are so worrisome. If it flat-out just didn't ever work to begin with, I'd strangely feel much better about it. I'm not sure I'll ever be able to drive the car without being nervous that it's getting ready to croak for some random reason. I'm now sending it back Holley for repair. Quite frustrated by the whole thing.

  2. #2


    Have you called Holley? Great tech support, perhaps you got one with a bad ECU or your handheld is acting up. Lots of us with trouble-free results, but with anything that has a computer, things can happen. Are you sure your wiring is correct? Lots of issues there, and often intermittent. I'd do a full wiring check and call Holley.

  3. #3
    Join Date
    Apr 2019


    What distributor & coil are you using? Do you have the Battery +/− wires going straight to the battery?
    Current Projects:
    62 Chevy II
    89 LX mustang

  4. #4


    I've talked with Holley about the issue. I was told to send the unit back as there was nothing that could be done over the phone.

    Distributor is a Holley Dual Sync, and timing control is being utilized. The unit has +12V during cranking and while running, 60 psi of fuel pressure, and is wired directly to the battery as instructed. My biggest concern is that Holley is going to call back and say there's nothing wrong. This means I'm left scratching my head about the reliability issues. I'm a mechanical engineer with an additional background in mechatronics. The installation was not confusing or intimidating and I'm 99.9% sure it was done correctly, which is evidenced by the fact that the car has intermittently run great.

  5. #5


    As a brand new Sniper owner, not even installed it yet, hearing things like this does have me a little worried. I've read hundreds of posts about the unit, mostly positive, but still many very similar to this one where everything seemed normal, than out of nowhere it just craps out. It also seems that there have been a lot of returned and replaced units, which also has me worried. Hopefully I get lucky and get one of the good units. Sorry to hear you're having these issues 68WASAGOODYEAR.

  6. #6


    Random shutdown and weird screen messages usually means RFI noise. The Sniper is very sensitive to RFI noise so you have to be super careful when routing the wires. You also need to triple check your plugs, plug wires, coil wires, etc.

  7. #7


    UPDATE: I received a reply from Holley that they were able to "recover" the ECU and that the unit is being shipped back to me. No explanation about what caused the poor reliability and unresponsive ECU. Back to square one in terms of figuring out what happened and how to prevent it.

    I'm using MSD 8.5mm plug wires with the EMI shielding and took care to keep them away from the Sniper wiring. Will double check this during reinstallation, but I'm fairly certain it's not the culprit. Also doesn't explain why the car ran fine one minute and ran like crap the next.

  8. #8


    UPDATE: I got the Sniper back from Holley and reinstalled over the weekend. Drove it this morning, and put 30 miles on the car with no trouble, until I got back home. Driving through my neighborhood at the posted speed limit, the coolant temp started to creep up. I have an auxillary electric fan for this to avoid overheating.

    As I pulled in my driveway, the coolant temp went over 190°F, and then it happened. Again. The IAC shoots up to around 30%, the car stumbles, dies, and will not start. It's sitting in my driveway now. At least I don't have to call a tow truck again.

    What's causing this? I have a 180° thermostat. I don't consider 190° to be overheating. It's hard to datalog for something that happens so quickly - on the road the car is running between 185° - 187°, so a quick jump to 190° is not something I can really react to fast enough. Does this have anything to do with the supplied Holley coolant sensor? If I go back out there and get "Searching For ECU...". It won't matter as I'll be boxing this thing up and shipping it back for good.

  9. #9
    Join Date
    Oct 2017
    Los Angeles


    Did you take a datalog?

  10. #10


    Just a few random thoughts on this. You haven't mentioned the make of vehicle, the age of the vehicle, or the type of engine where the Sniper is installed.

    Will the engine restart once it cools down? What coil are you using? Coils are weird little guys and can operate perfectly and test good until they get hot.

    You didn't mention at what temperature your cooling fan kicks on; does the shutdown event coincide with the cooling fan turn-on? Do you have the Sniper controlling the fan or are you using some other method like a toggle switch or stand-alone controller?

    If the shutdown event is tied to the fan turn-on; is the alternator up to the task? Computers don't like huge voltage swings and even though you have the Sniper wired directly to the battery, a fault in the charging circuit could cause issues.

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