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Thread: ECU failure?

  1. #41


    I wanted to try & test the harness like you suggested, SatherCS. I just didn't have enough time to play with it, so I went ahead & swapped the harness out. Plus, this also gave me a good excuse to reroute some wiring while I was at it.
    I've also added another ground from block to chassis. Had one previously, but it was a very old 4 AWG cable that was pretty sketchy, so I went ahead & replaced it with a brand new 4 AWG, and made sure it was going to a clean location.

    Going to try & run it today and see what happens. I'm hoping if it will idle for about 30 minutes straight, I can test it by running up to the store to get some gas. If it's still good after that, I may actually put a few miles on it today. Going to be mid 50s & sunny, so got to get it in when you can, right? Anyways, I will report back with my findings. Fingers crossed!

  2. #42


    Getting better, but no real solution to the random restart yet. Today it only restarted on me once, while it was warming up in the shop. I didn't trust it to not shut off on me while I was driving, so I just went to the gas station & back with the car.

    The other thing that has been plaguing me is the IAC. I can start the car and let it come up to temp and the IAC will be settled in around 5-8% like it should be. If I start playing with the throttle or move the car out of the shop, etc., the IAC almost never seems to want to settle back to that 5-8%. TPS will show 0% and the car will idle, but it will show anywhere from 20 to 30% IAC value. I think this is also contributing to the car wanting to push off the throttle. I will let of the gas to get ready to turn or just to stop and for a few seconds the idle won't drop to idle, and it will push the car forward as I'm trying to brake or slow down. It will eventually drop to idle (a few seconds later).

    I've verified by datalog that the TPS is not hanging during this time. The TPS clearly goes to 0% and the IAC & RPM hang up for a few seconds and then settle a little, but the IAC never really drops back to its idle value of 2-10%. Hoping I can get things ironed out a little bit.

  3. #43


    Check your Target Idle RPM at -40°F. If that one is low, it can apparently affect the warm idle RPM, causing it to idle high.

  4. #44
    Join Date
    Dec 2009


    Check the things in this thread:! (Holley Sniper EFI High Idle Thread)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  5. #45


    It's normal with the rest of the values. Thanks though.

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