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1 fuel injector not pulsing after engine gets hot.

Posted by rednesss, Jun 13, 2010

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  1. rednesss

    rednesss Proven Member

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    Bone stock '91 Eagle Talon TSI

    I'm having a bit of an intermittent problem. #2 injector likes to stop working after the engine warms up and is driven and then shut down; hop in car, run to store, turn off engine, come back, start it up and the car's running on 3 cylinders. After everything cools off, it works again. I put a noid light on the injector wire when it's not working and there's no juice to it, when I first start it up cold, the noid light works fine. I checked the resistor pack according to the manual, everything was at about 5.6 ohms. I'm at a loss, don't know what would cause it to do this when it's hot and not when it's cold, I thought for sure it would have been the resistor pack. Anybody got any ideas????
     
  2. steve

    steve DSM Wiseman

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    Did you check the resistor and wiring when it was failing or after it cooled down?
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  3. rednesss

    rednesss Proven Member

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    After it was failing, it had cooled down a bit. I'll try and get the problem to repeat itself and then test it immediately afterward and see if it is still reading around 5.6 ohms. If it is bad, where do I get a new one?? Is it a dealer only part??
     
  4. steve

    steve DSM Wiseman

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    I don't know if it's dealer only but you shouldn't have much trouble finding one in the classifieds or from Mitsubishi Graveyard.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  5. rednesss

    rednesss Proven Member

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    Measured it right after it was not firing #2 injector, and all of the pins came out around 5.6-5.7 ohms. It has 12v on both sides of the injector plug, could it be the ECU not closing the circuit??
     
  6. steve

    steve DSM Wiseman

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    Measure the resistance of the injector when it's hot too. I had one open when hot but measured good when cool.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  7. rednesss

    rednesss Proven Member

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    Will do, what would explain the fact that the noid light doesn't pulse when connected to the injector pigtail?? Could a bad injector cause the ECU to go gunny bag???

    Measured the resistance between the two poles on the injector itself, completely open, not making any sort of resistance like the other one that I measured. So I'm guessing that the injector is screwed up and is messing up the ECU.
     
  8. steve

    steve DSM Wiseman

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    Wouldn't explain it at all but before chasing the other direction it's best to make sure the injector isn't a problem.

    And I see it hits pay dirt. Replace the injector and see if your done.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  9. rednesss

    rednesss Proven Member

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    You know where I can get one cheap?? Auto Zone wants $187 for a new one. Youch.
     
  10. steve

    steve DSM Wiseman

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    I see people all the time selling 450 injectors in the classifieds. Usually about $50 for 4 of them.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  11. G-UNIT

    G-UNIT Proven Member

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    I'm having this same problem. Swapped in a working injector and the problem still exists.
     
  12. okm12346

    okm12346 Proven Member

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    Chicago, Illinois
    Just had the same problem this past weekend. Tried another set of injectors, another resistor pack and another 1g cam sensor and nothing, same problem. Installed my back up ECU and she ran on all 4 again. It was cyl 2 injector that wasnt getting pulse from ECU too.
     
  13. G-UNIT

    G-UNIT Proven Member

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    I swapped in a good ecu. Same problem.
     
  14. 93AWDDSM

    93AWDDSM Proven Member

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    Sorry for bringing this back but Mine is having the exact same problem as OP. When car is cold to medium warm it runs well, if it gets hot the injector fails to open intermittently. I've checked the injector resistor pack and it's all good. compression is good and I'm getting spark.

    - Not sure if it's old wiring that's frayed?
    - the injector seems to not open sometimes but others it's fine.

    any ideas? I'm going to hopefully swap some 560's into the car today.
     

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    1992 Eagle Talon TSi
    fwd · manual · 1G DSM
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  15. steve

    steve DSM Wiseman

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    Have you measured the injector resistance both cold and hot when the car is having problems?

    I had to replace injector that had gone bad and was open when hot.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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  16. 93AWDDSM

    93AWDDSM Proven Member

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    Yeah, when cold it shows between 3-5 on my on my multi meter when cold, but at hot i can't get a reading off of it!

    The symptoms seem corrects for a bad injector right?

    My bro had some 450 injectors ( my car is bone stock 92 TSi fwd) that were from his awd 92 but the tips of the injector insulator was like half inch longer than my 450 with shadow insulator tip. Point of that was it didn't work. Do I'm choosing wisely were I drive currently LOL, until I can get some new injectors and seals.
     

    Street Build 3K  5

    1992 Eagle Talon TSi
    fwd · manual · 1G DSM
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  17. steve

    steve DSM Wiseman

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    Yep, open coil when hot.

    All the original 1G 450cc injectors had the same single hole pindle caps, the 2G pindle caps have two holes intended to direct the injector spray into the two runners. Sounds like his may have had the pindle caps replaced with generic caps at some point.
     

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    1991 Mitsubishi Eclipse GSX
    manual · 1G DSM
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    93AWDDSM likes this.
  18. 93AWDDSM

    93AWDDSM Proven Member

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    Ok great, thank you for helping confirm it!
     
    Last edited: Jul 10, 2015

    Street Build 3K  5

    1992 Eagle Talon TSi
    fwd · manual · 1G DSM
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  19. JonHHHHH

    JonHHHHH Probationary Member

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    woodstock, Georgia
    New here and have the same issue on my Mitsu3000GT. What ended up being the fix? I've checked various things including ECU. I can start the car cold 100 times and drive no prob. But after warm, injector #1 is "open".... and misfire begins
     
  20. Mrspinkleswirth

    Mrspinkleswirth Probationary Member

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    West ashley, South Carolina
    Screenshot_20190824-145600_Drive.jpg well that's interesting, turbos have resistors because of high current injectors. I will see if I can did up some more info in a min
     

    229  2

    1990 Plymouth Laser RS Turbo
    fwd · manual · 2G DSM
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