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Old 07-01-2006, 09:41 PM   #1
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97TJ won't start

I have a 97 TJ with a 4.0 engine at 60,000 miles. I was driving it and it just stopped like it ran out of gas. Then wouldn't start. It did not appear to be getting spark from the coil, so I changed the coil and still not getting spark. Also, it does not appear to be getting fuel and now the gas gauge does not work. It has fuel becasue I added some thinking it may have run out of gas. I can't seem to get any codes and the check engine light does not come on when I turn on the key. The engine cranks over normally, just won't start. Any ideas? It seems odd that I don't have any spark or fuel at the same time.

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Old 07-02-2006, 12:40 AM   #2
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I have since taken the horn relay and placed it in the ASD relay spot in the PCM and that was not it. My latest research says it might be the CPS (crankshaft position sensor). That will cause the "no spark through the coil problem", but I'm not sure about the fuel problem. I will keep researching but would appreciate any advice.

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Old 07-02-2006, 02:54 AM   #3
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I'd bet on the CPS. A good way to check the fuel is to take the fuel line off of the throttle body and have someone turn the key on. Be warned, though. If you are, in fact, getting fuel to the TB it will spray out of the fuel line like mad. Have something handy to catch the gas in. I would suggest you pick up some flexible fuel line that barely fits over the end of the hard line and put the other end into a gas can.
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Old 07-02-2006, 09:29 AM   #4
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I have already unhooked the fuel line and tested to see if fuel is being pumped from the tank. It is not. If the CPS is bad would it effect both the spark from the coil and the fuel pump? I understand the the CPS controls the timing of the spark, but not sure about the fuel. I would think the fuel pressure would be there at all times even if the CPS is bad.
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Old 07-02-2006, 05:45 PM   #5
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We changed the crankshaft position sensor (CPS) and everything works fine now. The engine started right up and ran the same as it had before the problem occurred. You have to make sure you keep the CPS pushed up against the flywheel until after you have tightened the bolt. There is a piece of .030inch thick paper covering the end of the CPS that will maintain the air gap. When the engine turns over the paper will be ripped off and the air gap will be correct.
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Old 07-02-2006, 11:23 PM   #6
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good thing ya got it started...wouldn't wanna go without the jeep for a while
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Old 07-02-2006, 11:45 PM   #7
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Quote:
Originally Posted by 97BlueTJ
We changed the crankshaft position sensor (CPS) and everything works fine now. The engine started right up and ran the same as it had before the problem occurred. You have to make sure you keep the CPS pushed up against the flywheel until after you have tightened the bolt. There is a piece of .030inch thick paper covering the end of the CPS that will maintain the air gap. When the engine turns over the paper will be ripped off and the air gap will be correct.
Hey. I'm glad you got her runnin'. Thanks for posting your solution. This is the kind of thing that is going to be great for future reference. No doubt to help Jeepers in the long run. Good job.
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Old 07-03-2006, 04:50 PM   #8
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Sorry I was off the board all weekend, and as you figured out on your own the CPS can and will cause all of the problems you found. Glad you got it all taken care of.
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Old 07-04-2006, 07:17 PM   #9
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One more thing in case any one else has the same symptoms and are searching for a remedy to this problem: The fuel gauge and the voltmeter did not work. Also, we were not able to obtain any codes. Once we disconnected the CPS to test the sensor, the fuel guage and voltmeter started working. We were also able to read code 11 which basically told us that we had disconnected the CPS. This was the first sign that we may have discovered the cause of the problem.

So, if the CPS is bad, the fuel gauge and voltmeter will not work and you will not be able to obtain any codes through the key-on 3 times and key-off 2 times method. The check engine light, by the way, never came on before the CPS failed. Also, you will not get any spark through the coil to the distributor and you will not get any fuel to the injectors.

There was nothing that ocurred beforehand to make us think that something was about to go wrong. It just failed all of a sudden.

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