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Unread 06-20-2004, 10:22 AM   #1
options13
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Join Date: Jun 2004
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4.0 turns over but no start

this morning my wife's Grand Cherokee turns over fine, but won't start. Fuses are fine, but I don't hear the fuel pump. I don't remember if I could hear it before, though. Oddly, though, is the fuel gauge shows empty. I added 5 gallons & it still won't budge.

I would think the fuel pump is bad, but the fuel gauge not working makes me wonder if there is something I am missing??

Also wondering if the Jeep has a safety cut off swith like most Fords??

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Unread 06-20-2004, 05:15 PM   #2
jeepilot
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I recomend checking the Crankshaft position sensor, and the camshaft position sensor. If these sensors have gone bad, the jeep will turn over just fine, but will never fire. Pick up a Haynes or Chiltons manual at your local auto store to check the voltages. If it's a bad fuel pump you'll usually be able to start the vehicle, but it will soon die. Also wouldn't hurt to check the battery.

What do you mean by safety cutoff switch?
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Unread 06-20-2004, 07:18 PM   #3
Silver yj
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What do you mean by safety cutoff switch?[/QUOTE]
Its a switch made to cut the fuel pump off when you are in a wreck or if you hit a bump hard enough it will also cutoff,had that happen once before.As far as I no Jeep dosent have one.
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Unread 06-22-2004, 06:00 PM   #4
troutslayer
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Quote:
Originally Posted by options13
this morning my wife's Grand Cherokee turns over fine, but won't start. Fuses are fine, but I don't hear the fuel pump. I don't remember if I could hear it before, though. Oddly, though, is the fuel gauge shows empty. I added 5 gallons & it still won't budge.

I would think the fuel pump is bad, but the fuel gauge not working makes me wonder if there is something I am missing??

Also wondering if the Jeep has a safety cut off swith like most Fords??
Oh man, believe me...I have been through this before!! Here are some things to check:

Unscrew the cap on the fuel rail for your fuel injection.Have someone turn the key while you depress the needle inside the fuel rail with a screwdriver.If you get a spray of gas shoot out the rail, you will know your fuel pump is fine.If you do not get the gas spray shoot out but get a few drops of gas, your fuel pump is probably shot.

You didn't say, but if your jeep is equipped with an alarm system, yours could be bad and it won't start even with an act of god.I replaced my alarm once with a new module from Mopar and when it went bad, I bypassed the whole system.

The Crank position sensor and cam position sensor as mentioned could very well be the problem


There is a way to check for error codes using your key.I can't remember the sequence, it was something like on/off,on/off,on/off,on/off then on again leaving the key to the on position.The check engine light should flash so many times then it will pause and then flash again.You want to record the number of times the light flashes for each sequence.This aids in determining if there are any sensors that have gone bad.

I hope this helps.It is a weekly chore for me to keep my jeep running
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Unread 07-02-2004, 07:13 AM   #5
options13
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Fixed!

Well, my mechanic diagnosed it as a bad PCM, but after installing one, it still didn't work. So, he went back and found that the crankshaft sensor was bad and causing some weird codes. The crank sensor was the problem. Anyone need a good PCM, he still has it on the shelf.
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