intermittent no idle

Discussion in 'Diagnostic & Repair Tech' started by Holmsey, May 16, 2017.

  1. Holmsey

    Holmsey Member

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    Hi this really is all that is stopping me enjoying my Lexus conversion now. It always needs a bit of throttle to start, wont just start on the button. sometimes it will idle ok, if I rev it and let the accelerator pedal return it usually cuts out. Then is often hard to restart, will start if I keep the throttle wide open.
    Pain in the A*SE when coming up to a junction if I don't keep a bit of throttle on it cuts out, but next time it might idle ok.
    It pulls like a train no misfires or hesitance just the idle problem, I have no fault codes. I've set the TPS, cleaned the IACV (though i'm not convinced it is working, is there a way of testing it?
    New O2 sensors, new temp sensor, crankcase sensor, cambelt etc.. all new condensers in the ECU.
    Any one point me in the right direction where I can look to sort. Cheers.
     
    Last edited: May 16, 2017
  2. gloverman

    gloverman Well-Known Member

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    Which ECU number?

    Test - Unplug IAC. Testing light into one of the middle pins. Start engine and run for 20 seconds , might need some throttle. Turn engine off and tell me if the light goes out straight away or stays on for about 4 seconds. Cheers
     
  3. Holmsey

    Holmsey Member

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    Thanks Gloverman you have come to my rescue again ;o)..... I will do that and get back to you. Just tightened the throttle cable to cheat a tickover for now. I will do the test you suggested not in garage now until Thursday it will be my first task as its a two man job I guess. My ECU is 89661-50160. you did help me with my Oxygen sensor problems a couple of week back.
     
  4. gloverman

    gloverman Well-Known Member

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    No worries. I work on my own a lot so can do that test on my own but it's easier with someone else. I complete the same test at the ECU on pin A28 as well to comfirm thats correct too. Cheers
     
  5. Holmsey

    Holmsey Member

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    Hi just checked the IAC with my test light. Started the engine ran for 20 secs and the light went out straight away when I turned off the key. So what does that indicate? Cheers for your help mate.
     
  6. gloverman

    gloverman Well-Known Member

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    Its not wired correctly. Who wired the engine in?
     
  7. Holmsey

    Holmsey Member

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    I had a guy do the loom for me Bushwacker he had done quite a few. I t then wired in the loom to my Truck. So what wires do I have wrong?
     
  8. gloverman

    gloverman Well-Known Member

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    All of bushwackers early looms had the same issue. Ive sorted a few of them now. PM me and Ill make a few pointers. cheers
     
  9. Holmsey

    Holmsey Member

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    Hi Gloverman, I am not sure how to send you a PM.. I have been on your profile and sent a message not sure if it's a PM ;-).. my pm is holmseyd@talktalk.net Cheers
     
  10. uknuta713

    uknuta713 New Member

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    Hi, i am having the same stalling issue, i have tested the Iac to ensure it is working, but same thing with no CEL or fault code. How did you end up sorting your one out? Thanks.
     
  11. gloverman

    gloverman Well-Known Member

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    It had an issue with the wiring.
     
  12. uknuta713

    uknuta713 New Member

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    I woner if i have a similar issue, I may have missed something as i wired this myself. I have power to all sensors and injectors and the car runs perfect when driving but just stalls, sometimes idles when it is warm but the idle is so low, and when its cold it won't idle at all. Would you be able to offer any info on what to check?
     
  13. gloverman

    gloverman Well-Known Member

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    Easy test. Remove the plug from the IAC. Turn key on and check for 12 volts at one of the centre pins. Will still keeping test light connected start the engine and keep running for twenty seconds. Turn engine off and monitor power. Tell me if it turns off with key off or holds for a few seconds. Also which version of engine and ecu number do you have?
     
  14. uknuta713

    uknuta713 New Member

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    I have tested with a multimeter that i have 12V on the plug but i will test again in the manner you decribe. I will let you know ecu number later. Not sure what version V8. It was out of a 92 Ls400.
     
  15. uknuta713

    uknuta713 New Member

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    Hi Gloverman, i have rechecked the iac and have 12v on both centre pins. I hooked up a test light between one of the pins and e1 at the diagnostics port, the car idled high above 2k then started hunting a bit. Turn off with the key and it shutdown straight away. The ecu no is 89661 50180. What does the test idicate? Thanks for your help.
     
  16. gloverman

    gloverman Well-Known Member

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    It means it's not wired correctly and won't idle correctly as a result. Look over your diagrams again.
     
  17. uknuta713

    uknuta713 New Member

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    Thanks for your help on this. The diagrams i have are from the lexus manual, i have both ucf10 and 20 and the pinouts are different. Can you offer any advice on where to start looking with the wiring?
     
  18. gloverman

    gloverman Well-Known Member

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    Maybe best to flick me a PM. Cheers
     

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