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Thread: Bad ECU?

  1. #21

    Default Bad ECU?

    Yeah, I saw the video. Note I said IAC in Neutral. It Should be lower in gear based on lower idle and more load. Since IAC in N is lower showing the blades are closed, my comments stand.

  2. #22

    Default Bad ECU?

    Okay, went out to adjust IAC to 5-15 at idle in neutral and it seems near impossible now. Even 1/12 turn of the adjustment screws results in wild fluctuation. Finally got it to a fairly steady 3 in neutral and when it put it in gear it immediately begins to climb slowly (over a minute) to 175 and begins to stall. When I put it in neutral the IAC does not return, it will stay at or near the last value it reaches before I return it to neutral unless I accelerate to 1500 RPM or so, then it will slowly return toward zero. Sometimes it stops at 40-60 and stays there, I adjust the screw 1/12 of a turn open and it goes to zero over a minute. Go back 1/12 a turn and it stays at zero. Put it in gear and it begins to climb. Backed both screws out to no tension, opened 1/2 turn each and began procedure again with same results. Reset atomic defaults and no change. Of note is if i turn the engine off, the IAC remains where it was when I shut the engine down, even after reset to defaults, not sure if that means anything.

  3. #23

    Default Bad ECU?

    Finally got IAC to steady 8 in neutral idle for about 5 minutes. Put in to gear and goes to 30s, back in neutral stops at 18, back in gear goes to 40s, neutral stops at 24. Turn engine off long enough for handheld to shut down and then crank again, IAC now at 8. Put in gear and increasing IAC cycle starts again, power down and it is back at 8. Since I have installed the unit, have never once seen IAC go down with vehicle in gear, always creeps up.

    Seems like every time I shut the engine down and let it rest for a while, it behaves totally different the next time I go back to it. Think it must be haunted

  4. #24

    Default Bad ECU?

    The last few folks here have been having IAC motor issues and once it was replaced everything was good. I believe that its available at parts store for around $40.00 but you should probably get MSD inputs on this issue too.

  5. #25

    Default Bad ECU?

    Anybody have PN for IAC motor, MAP sensor, WBO2 sensor. Figure if I replace those it pretty much has to be an ECU problem. Apparently MSD wont check this till Monday and I'll be back at work for 5 - 12 hour shifts starting Monday. Makes it pretty hard to install Saturday morning and make the cruise Saturday night, if tech line and forum are only open during the week.

  6. #26

    Default Bad ECU?

    Have you checked to see if there are any error codes when the motor is acting up?

  7. #27

    Default Bad ECU?

    There have only been 1 MAP sensor error after a backfire and 2 O2 sensor errors I think related to backfire as well. All of them cleared and did not return. I believe they were H codes

  8. #28

    Default Bad ECU?

    There have only been 1 MAP sensor error after a backfire and 2 O2 sensor errors I think related to backfire as well. All of them cleared and did not return. I believe they were H codes

  9. #29

    Default Bad ECU?

    I found this:


    BWD 21813 can be found at O'reilley's

    O2 Sensor

    BOSCH 17018 can be found at Auto Zone

    MAP Sensor

    MSD P/N 2933 can be found at Amazon and Summit besides MSD. This part seems to be unique to MSD.

    I was watching your video again and the MAP reading is jumping all over the place. What is the reading when your engine is running like this and you turn it off with Key On? An incorrect MAP reading would throw your A/F off and with the high A/F ratio the motor is running really lean.

  10. #30

    Default Bad ECU?

    Thanks for the info, really appreciate all of your help. Guess I will have to hold off replacing them for now as MAP sensor will probably not be available locally. Will get on amazon and see if I can get them headed this way. Current MAP is 29.5 hg with the engine stalled and key on. Current barometer reading here is 30.07 and rising so I guess that is pretty close

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