Sniper EFI Issues (Need Advice)

Discussion in 'High Tech for Old Iron' started by 68Rivi_In_Cali, Nov 1, 2018.

  1. 68Rivi_In_Cali

    68Rivi_In_Cali Well-Known Member

    This is for my Buick guys running the Terminator EFI or the Sniper EFI.

    I Installed the sniper EFI system on my 1970 Buick Skylark. Has been running great up until one day I noticed I kept hearing a hissing sound coming from the dash. The heater systems in these cars use vacuum to run the switches, I thought it was just a small vac leak and drove the car like this for a week or two, short trips.

    Last week I had to use the Skylark as my daily to school and then to work for 3 days due to my daily driver having the suspension worked on.

    It was fine for 2 days then one day I kept hearing the hissing noise and noticed an odd stumble off idle in stop and go traffic. Made it near school and it was running rough.

    Turns out the hiss was a collapsed PCV valve hose coming from the back of the Sniper unit, going to the PCV valve on the intake.

    Had spare hose in the trunk, cut it to size and off I went to school to not miss class. I noticed the off idle stumble was still happening but the car managed to run a bit better. Figured the Sniper unit would retune itself.

    after school drove to work and it was having a stumble off Idle and and when deceleration. The AFR was spiking 20+ which means leaning right?

    After work I took a closer look and my PCV Grommet was torn and very soft. It was leaking air. Had to limp the Buick Home. I had to keep my foot on the throttle at stop lights to keep the engine running a bit smooth and had to stop halfway home to let it cool off since it was beginning to over heat in traffic. Car finally got hot 230 degrees, pulled over, walked to a Pep Boys down the road, bought a ton of grommets and installed it after it cooled down.

    Turned the car on and it ran perfect! Was super smooth accelerating and made it home after traffic died down.

    Now the next day, ran some errands and when the car is cold it runs fine and idles well. Once it is warmed up, it has the off idle stumble/ AFR spike. it also happens when decelerating.

    I tried running the wizard again to have it relearn the tune but after the engine warms up, it is back to doing the same. This time, it will idle nicely and after a few minutes it randomly begins to spike the AFR up to 20-25 and then cuts out or runs rough.

    I have looked into the Holley forums and downloaded the EFI software but do I need the USB to clear the potentially corrupted tables?

    I have read that I might need to look at the AE settings , acceleration enrichment settings but then again I have yet to mess with any of that.

    Can I just install it on the SD card and fix the car?

    Is there a way the Tables might have been corrupted from holding the gas pedal at lights in order to keep the car alive?

    I adjusted the IAC down to 2% when in idle and now it doesn't go Lean randomly while in idle.
    It still has an off idle stumble and sounds like it runs rough. I have changed the spark plug wires to rule out a misfire. New grommet and also sprayed the base of the throttle body to search for vac leaks as well.

    I do have Data Logs if anyone can help it would be much appreciated. Thanks!
  2. BillA

    BillA Well-Known Member

    Did you buy the complete Sniper system with the fuel pump? I have the Terminator system and I know from experience they are sensitive to fuel pressure. I had a 200lph pump that could not keep up with the demand and every time I laid in to the throttle i would get a stumble and a lean spike on the AFR gauge. I had to upgrade to a 340lph pump and the problem went away. You said it was running great for awhile and then started acting up. How long was it running fine? When I first installed the Terminator system I had to call Holley tech a few times to make a few minor adjustments. Their tech support is first class. Did you upload the data logs to the Sniper/Terminator forum? There is a guy on there named Danny and he can probably make a diagnosis based on what he sees in the logs. Give it a try. Good luck. BTW, I now have an LS in my Skylark but I installed the Terminator when I still had the 455.

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