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2001 Jeep Wrangler Question: Engine cranks over but does not fire

 

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usmc1981, West Bend, WI, May 25, 2014, 10:24
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Engine cranks over but does not start, here is what I have tried so far with no luck......starter fluid in throttle, new crank sensor (two times), new cam sensor. No dash gauge (fuel or volt) movement with ignition in the on position. I get a brite test lite reading at one terminal (ASD fuse) terminal and a dim test lite on the other (ASD fuse) terminal with ignition on the on position. I am getting no power to the 20 amp injector fuse...any thoughts on what is causing this????

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  • Medium-star Best Answer
    May 25, 2014, 10:32
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     Master

    Pull that fuse and test it with a dvom.., light should be the exact same on both sides!!! ASD relay clicking on/off with key turn? Test every fuse, and anyting that looks like a fuse, you can find with the test light...no matter what circuit it's protecting... test it.!... THANKS FOR SERVING!!!!!

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    usmc1981, May 25, 2014, 10:43
     Rookie

    All fuses are good. ASD relay is not clicking. I replaced the ASD relay with a new one and still no clicking. This is what is odd...I removed the ASD fuse (30 amp pink box type fuse), turned the ignition to "on", when I test the ASD fuse box terminals with my test light, I have bright light at one terminal and a dim light on the other, almost like it's getting some sort of back feed.

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    pushrod, May 25, 2014, 10:51
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    Check wiring from fuse block to pcm for possible rodent (mouse) damage! With key on all fuses in place... 'wiggle test' wiring haress to see if any clicking etc can de detected.... sounds like a poor or open circuit/connection. Ground circuit to the ASD relay is provided by the pcm....

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    usmc1981, May 25, 2014, 11:07
     Rookie

    Ok.. I did try wiggling and pushing on sensors, harness and everything, no change. I tried scanning the pcm with two different scanners and linking to pcm failed to communicate. Also I have no power to the 20 amp "injector" fuse with the key in the on position, checked while cranking engine and still nothing at the the fuse. And, why are my dash fuel and voltage gauges not reading anything, with the ignition "on"?

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    pushrod, May 25, 2014, 11:21
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     Master

    Message in odometer say "no bus".? All other accessories work with key on?... Possible ignition switch failure...... all guesses of course!! Tough to diagnose online!

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    usmc1981, May 25, 2014, 11:28
     Rookie

    NO message on the odometer, other then the actual odometer reading. I thought about the ignition switch but I am getting power to the fuse box, when I turn ignition to "on". And originally the jeep died while it was being driven...thats when all of this started. I tested the injector and I am getting no noid light. I know it's just a guessing game now, but do you think it might be the pcm????

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    pushrod, May 25, 2014, 11:40
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     Master

    Ignition switch has more than one circuit.... pcm is certainly a possibility but that would be my least likely suspect.
    Good luck Marine!

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    usmc1981, May 25, 2014, 12:01
     Rookie

    Thanks for your time and advice....Semper Fi

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    pushrod, May 25, 2014, 12:14
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     Master

    What's that saying.... adapt and overcome... you got this one..!! Take a break and think about it a bit....

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    usmc1981, May 30, 2014, 18:39
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    Well....I finally figured it out, it was the ecm. Thanks everyone for your HELP....Semper Fi!!!

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    May 25, 2014, 18:41
     Master

    Just adding my 2 cents(actually now only worth 1/2 cent) to pushrods dime, see if you can get 'fast codes off the odometer--- 'key-on, key-off , key-on , key-off , key-on'...............OR if it's easier to read ---on-off-on-off-on, third 'on' leave it on and if there are any codes stored , they will display in the odometer (digital , I'm assuming) , you can do that more than once , to verify what you didn't get to right down the first time.AND I'll double-up on pushrods "thanks for serving" I got chased out of brooklyn at the physical (1979) for my knees popping doing the 'duck-walk' , I think it worked out for the best though , cause I always thought if they gave me a gun , I'd end up like the wacko in 'Full metal jacket' , if you know what I mean.......anyway thanks again and hope you get it figured out. Check our profiles.......maybe that be 'splainin a little........ reply to this and I can tell you about 'green jelly!...........one other thought...........Unlike a friend of mine who always got pissed at his truck (17 year marine vet) DON'T keep 500 rounds of ammo in your truck while working on it!!! Trust me , it won't work out well!!!

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    usmc1981, May 26, 2014, 15:15
     Rookie

    Odometer is digital but not showing anything other then the odometer reading after doing the three on/off trick...Thanks for the info and it's a good thing I do not have any C-4!!!!!

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    ziptie12, May 26, 2014, 18:10
     Master

    Uhm.............yeah. Sorry you got nothing on the odometer , but I forgot to mention , if that doesn't display codes then the engine light might 'flash' them. Maybe?

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  • Answer #3

    May 26, 2014, 08:45
     Rookie

    I just had the exact same thing happen on my 99 cherokee sport, 2 days ago.
    My neighbor broke out a mitchells repair manual and we found that between the pcm and the crankcase sensor there is a critical speed switch which plugs into the rear of the transmission. Thats where I found I lost my connection.
    check there for your 5vdc. If you have it there and not at the cps the critical speed switch is the culprit. No manual or forum brought this up as a possibibilty. Good luck.

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    usmc1981, May 26, 2014, 15:17
     Rookie

    Did you pull the ASD fuse and check to see if you were getting a low voltage back feed at one of the terminals with the ignition switch at the "on" position???

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    bsw4aker, May 26, 2014, 15:26
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    Check the critical speed sensor. Rear of the tranny case under the drivers side. This worked for mine. All my guages came back to life and 5vdc began running through the system.

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    usmc1981, May 26, 2014, 15:59
     Rookie

    Dang it....I have 5vdc at the speed sensor and the cps....Back to square 1.

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