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Old 04-30-2010, 12:25 PM
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Join Date: Apr 2010
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98 4.0 fuel pump problem

I replaced the fuel pump in my TJ last fall, a wonderful 2 day project due to an aftermarket tow hitch that caused clearance problems for removal of the tank!

A couple of days ago, I started the Jeep to leave for work, it ran about 10 seconds and died. Wouldn't start. Tried for about 20 mins, no start. Checked connections, checked for fuel on the rail, even gave it a squirt of starter fluid but no start.

Waited a day, added a couple cans of Heet (the last time it wouldn't start was from water in the fuel). Still no start.

Day 3 - it cranked and sputtered twice then caught and ran fine for about 2 minutes, and then shut off. Now there is no action from the fuel pump when the key is turned on. I traced the wired from the junction near the tank all the way to the power block by the battery, no problems I could see. Swapped the relay with the Horn, horn worked with the pump relay, so that's not the problem. I replaced the Crank sensor last fall when I replaced the fuel pump. Same with the coil.

The only other thing I can think of is if there is a pressure regulator or sensor that is telling the pump there is enough pressure and the pump won't run? Or the ECM has gone TU and is ready for burial.

Any suggestions or experience with a ghost in the tank turning off their fuel pump?

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Old 04-30-2010, 02:23 PM   #2
Knows a couple things...

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Join Date: Nov 2005
Location: Escondido, Calif.
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The PCM will shut the power off to the fuel pump if it's not happy with all inputs from the various sensors like the crankshaft and camshaft position sensors or if there is enough fuel pressure at the rail. Have you checked to see if your coil is producing spark?
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