Thread: Have a mystery

  1. #1
    icecastle's Avatar
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    Question Have a mystery

    I need some help.Have a 91 YJ with 2.5L fuel injected.It was running fine then I parked it in garage for 3 weeks.When I went to start it it wont fireI have checked the fuses,the timing,has good spark.I can hear the fuel pump build up and shut off after you try to srart it a few times you can smell gas at tail pipe.Need help please thanks.

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    Re: Have a mystery

    I assume that "won't fire" means that the engine is, at least, turning. I'd start with the rotor and distributor cap. If that doesn't fix the problem, I'd then replace the ignition coil. It's clearly an ignition problem, so I'd bet that one of these items would be an easy fix.

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    Re: Have a mystery

    It does have realy good spark.But doesnt even try to fire.Could it be something in the computer? the codes that I get are11,33,12,55does that give any more of an idea? thanks

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    Re: Have a mystery

    the book shows no code 12 maybe 21 witch is oxygen sensor or circuit orcheck plug connecteror

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    Quote Originally Posted by icecastle
    It does have realy good spark.But doesnt even try to fire.Could it be something in the computer? the codes that I get are11,33,12,55does that give any more of an idea? thanks
    You answered your own question. Code 11= ignition problem. So I think you need a new ignition coil. I know you said you get a spark but does the job go all the way through the rotation? Just a thought: your ignition coil may be good but what this code is telling you is that it could be anything between your ignition and the spark plugs. So look very carefully at each part for damage and take age into account. But I would replace the coil.

    And code 33 is ac relay just FYI.

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    Re: Have a mystery

    maybe a mouse made a new home? pop the hood, and check the wires...
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    Re: Have a mystery

    oops the code 12 was typo code 13 instead.The spark is realy hot will jump about 3/4 "with plug out.Just wandering if getting full fuel through the inj.just checked it is 40# when cranking is this a norm when not running? thanks

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    Quote Originally Posted by icecastle
    oops the code 12 was typo code 13 instead.The spark is realy hot will jump about 3/4 "with plug out.Just wandering if getting full fuel through the inj.just checked it is 40# when cranking is this a norm when not running? thanks
    There is no code 40, but there is a 41 and 42. They both deal with an opened or shortened circuit either in a relay or between a fuel sending unit and a control circuit.

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    Re: Have a mystery

    That isnt code 40 rather 40 LBS of pressure sorry. Thanks

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    Re: Have a mystery

    Ok here is an update read something in another thread about too much fuel.thought I would try messing around that direction.I pulled out the fuel pump relay and cranked till fuel press. dropped then it started to fire.Then put relay back and it started up and ran good.Now any ideas about that? The fuel pressure now when runing is 31psi W/vacuum line hooked up and holds that when off.

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    Re: Have a mystery

    The fuel pressure should be something like 31psi and 39psi, one for vacuum and the other without.

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    Re: Have a mystery

    Quote Originally Posted by icecastle View Post
    Ok here is an update read something in another thread about too much fuel.thought I would try messing around that direction.I pulled out the fuel pump relay and cranked till fuel press. dropped then it started to fire.Then put relay back and it started up and ran good.Now any ideas about that? The fuel pressure now when runing is 31psi W/vacuum line hooked up and holds that when off.
    now your having no troubles firing it up?

  13. #13
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    Re: Have a mystery

    I have tryed it mabe a dozen times now seems ok even run it til hot then tryed still ok.

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    I love it when stuff practically fixes itself. Don't know what else to say really. I guess just drive it til it breaks again. :shrug:
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    Quote Originally Posted by icecastle
    I have tryed it mabe a dozen times now seems ok even run it til hot then tryed still ok.
    Well, I always say if it ain't broke, don't fix it. Lol

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    Re: Have a mystery

    thanks guys.This is the best site for info.

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