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2007 Pontiac G5 Question: 2.2 - #2 cylinder injector not firing - engine misfiring

 

Question

mecknic, Hubbard, OH, February 24, 2014, 17:38
 Rookie

preliminary - all cylinders check 150# & above for compression - replaced coil and plug (original plug loaded with carbon) - visually seen solid spark on #2 plug when checked having spark plug in coil plug laying on top of engine. No change - Injector black with carbon - replaced injector - no change - could not get electrical reading off of plug to injector - seems to be electrical problem - what should be checked next.

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  • Answer #1

    gregfedor from Youngstown Mechanics, February 24, 2014, 18:02
     Technician

    Go buy a noid light to see if you have power and a signal to #2 injector if u have no pulse then it's a computer or wiring

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    mecknic, February 25, 2014, 08:27
     Rookie

    tks - will do then follow up...

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  • Answer #2

    G. T. Service Center (4142 Answers) , Stephenville, TX - (254) 638-3236
    ProfessorG February 24, 2014, 18:09
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     Master

    Agree with noid light test. Has to flash while cranking and no light with key on not cranking.

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    mecknic, February 25, 2014, 08:28
     Rookie

    tks - if wiring, tracking down should be "FUN" - probably better for a wiring issue than computer issue...

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    gregfedor, February 25, 2014, 09:36
     Technician

    Probably not a computer issue and wire tracing is fairly easy on the Eco techs good luck you can call my shop at 3303333997

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    mecknic, February 26, 2014, 17:03
     Rookie

    Well, this was an adventure - brother-in-law has noid light (and valued help, opinion and assistance) - checked all four cylinders - 1, 3 & 4 fired at injector plugin point but not #2. Removed section of wiring harness which fires fuel injectors and checked with V/O meter - this portion of wiring harness checked good. OK, it must be wiring problem or computer problem before electrical current reaches section of wiring harness which was checked as referenced above. My brother-in-law began to inspect wiring harness backwards from connector point of harness which fires injectors. He found that a portion of the main wiring harness (which connects to the portion of the wiring harness which fires the injectors)was resting/laying against the HP tube/pipe of the air conditioner. As he inspected, he found that the slit in the plactic covering around the wiring harness was against the AC pipe. A green wire from the wiring harness worked its way through the spit in the plastic covering. Guess what - the wire went to #2 injector. The wire was melted causing a short. The wire was cut, cleaned then soldered and taped. We then zip stripped the harness to an upper position keeping it from touching the AC tube. Put everything back together and WALAH, the engine purred like a kitten. Well, I hope this short story helps someone down the road - check and MAKE SURE the wiring harness is not rubbing or resting on any surface (hot or cold). Had I taken approx. 5 to 10 minutes to check the harness as a whole, the problem MAY have been solved much earlier. Oh well, live and learn. Tks guys in OH and TX for your help - the noid light really isolated the problem then Columbo took over!!! art

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    ProfessorG, February 26, 2014, 17:08
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     Master

    Good job. Things we deal with every day. Enjoy

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