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Thread: Code P0201 cyl #1 fuel injector problem. Help!

  1. #1
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    Code P0201 cyl #1 fuel injector problem. Help!

    This problem is intermittent. It runs fine while engine is cold after a fine start. After a few miles driving (10 min), the engine start running uneven, not all the time, off and on for a few more miles (5 min). Then it's constantly running uneven.

    A quick check at AutoZone shows the codes P0201 (electrical circuit for cyl #1 fuel injector) and P1343 (misfire cyl 1 with fuel cut-off).

    I replaced the coil. Ohm'ed the injector. Replaced the spark plug. Cleaned contacts at the injector and at the coil. Inspected and ohm'ed the boot connector between coil and the plug. Measured the high voltage contact at the injector connector coming from ECM (read 12V). Can't really take volt measurement at the 2nd (open collector) contact. Bentley says you'll need an oscilloscope which I don't have.

    I ran half a tank with injector/fuel cleaner. No difference.

    I'm thinking it might be the ECM. Is there an easy way to verify that?

    Maybe electrical contact between the ECM to the injector? What could it be that's so temperature dependent? Am I missing something? Could injector become faulty when hot?
    _____

  2. #2
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    I'd get a dealer diagnostic in this case, pay him and then DIY (or let him do it if it's a sensitive ECU problem)
    0.02

  3. #3
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    bump
    _____

  4. #4
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    When you ohm'd the injector, what was the reading? Was it within spec?

    I assume you know what you;re doing.

    TO answer your question about the heat. In short, YES, heat will make it behave differently. Over time heat will break down the insulation on the coil windings internally. Once it becomes hot, the insulation will fail more easily and cause a short. This short will be read from the injector back. So all points from there may show a fault. The connector, circuit continuity etc etc etc. I would replace the injector and see. Or, ohm test the injector at full operating temp. You should get a more erratic ohm reading, espacially compared to the rest of the injectors. Those should be Ohm tested too, so that you can have a comparison basis.

    If it was me, i would be 90% sure the injector has to be replaced.
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  5. #5
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    Thanks for the insight. I don't remember the values now. But when I ohm'ed those parts, I compared them with values in Bentleys and with the adjacent working cylinder's (rubber booth's resistive value also printed on the sleeve). I'm picking up injector from the dealer this afternoon.
    _____

  6. #6
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    I'm having the same problem

  7. #7
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    The injector is bad.

    Its rare for an injector driver in the DME to go out and especially intermittently and climate changes. Swap injectors....fault should follow.
    '02 E39 530i/5sp Topaz Blue/Black Interior - MegaSquirt3x - Garrett GTX3582R turbo - E85 fuel - Apex FL-5 - 265/295 tires - Custom Porsche Brembo BBK - 600whp @ 22 PSI
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  8. #8
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    Quote Originally Posted by JackEatsEmoKids View Post
    The injector is bad.

    Its rare for an injector driver in the DME to go out and especially intermittently and climate changes. Swap injectors....fault should follow.
    thank you. is there a guide somewhere that will direct me in the right direction regarding removing/installing my injectors?

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