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Thread: ECU failure?

  1. #21

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    Did you notice any difference going from a variable to fixed PCV?

  2. #22

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    Can't say I did. I was in the process of fine tuning the idle, and figured I take out any variable I could. Popped it in and have had no reason to remove it.

  3. #23
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    It only costs 99˘ (LINK), and very easy to replace: https://forums.holley.com/showthread...1540#post51540 (Related Forum Post)
    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

  4. #24

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    Well back to square one. Seemed to have eliminated the RFI I introduced by rerouting plug wires to close to ECU.
    Started the car today and same thing again.
    1st start ran 3 seconds, died, immediately primed.
    2nd start ran 8 or 9 seconds, died, immediately primed.
    3rd start ran 20 seconds, died, immediately primed.
    Etc, etc, etc.

    I captured the 1st two starts on a datalog and looked at them. No RFI apparent. Sent them to Ty P. at Holley. He confirmed that no RFI was apparent and no apparent drop in RPM signal.
    At this point, it seems the length of the run is directly tied to Sniper temperature. The more it runs, the warmer it gets and the longer it stays running before dying.
    Holley hasn't seen this before and Ty wants to have a few more techs look at it and see what they can come up with.
    My thought is some internal connection in the ECU is shorting and it's more apparent with colder temps. What do you guys think?

  5. #25
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    This seems like a bad connection somewhere. Sometimes the multimeter will indicate +12V/Ground at rest or key-on/engine-off, but then lose connection when the circuit is alive (nominal voltage, but can't support any amperage draw).
    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

  6. #26

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    I see what your saying Danny, but I thought directly connecting to the battery would eliminate that possibility of it being external to the EFI unit.
    Also, what has me perplexed is that without fail, every time I run the car now, the time it will run before shutting down grows each time I start the car.

    The only thing that changes as the car runs more & more is the temperature of the engine bay components.
    Wouldn't make sense for it to be related to a mechanical or relay issue if small temperature changes elongate the time it goes before failing.
    I'm just stumped as to why it suddenly started this and to what's causing the run times to be connected to engine bay temps.

    If you remember when I heated the shop up to 70°F, the 1st run died immediately, but then the 2nd run lasted for so long I shut it down myself.
    The warmer the temps the longer it runs before shutting off and cycling to prime immediately.

  7. #27
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    Heat related ignition coil failure? Maybe watch a timing light while this happens. Although, the fact that it reprimes the fuel system leads me to think it's losing the switched +12V pink wire. Have you checked that wire for chafing, pinched, burnt, damaged, loose connector terminals/unseated pins, etc.? Perform a "wiggle test" (Ohms continuity test while wiggling harness at idle) on that wire.
    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

  8. #28

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    I may go pull the ECU wire out from the harness completely and check it inch by inch. Still baffles me that it's so repeatedly failing in the same manner.
    So ECU power looks fine and doesn't seem to be an issue. I directly connected it again. First two starts died & reprimed. Third start stayed alive and everything came up to temp, and I let it run waiting to die, and 10 minutes later still running.
    Not sure if this is an indicator of anything, but when it dies & reprimes, I get a locomotive amount of smoke from the IAC port that just continues to puff out fuel vapor for a few minutes? Possibly the fuel evaporating in the intake?

  9. #29
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    Quote Originally Posted by Outcrydrummer View Post
    Not sure if this is an indicator of anything, but when it dies & reprimes, I get a locomotive amount of smoke from the IAC port that just continues to puff out fuel vapor for a few minutes? Possibly the fuel evaporating in the intake?
    Maybe that's related to the lifter/camshaft lobe problem.
    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

  10. #30

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    Quote Originally Posted by Outcrydrummer View Post
    I directly connected it again. First two starts died & reprimed.
    So, in this case, it still dies & automatically reprimed without any pink wire connect disconnect?

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