Mechanics

JEEP WRANGLER FUEL PRESSURE PROBLEM

1995 Jeep Wrangler • 90,000 miles

I replaced my fuel pump a week ago wich solved my problem of no fuel pressure thought I was in the clear. Yesterday it left me stranded no fuel pressure again except after 2 hours it started up. Then today no fuel pressure. Upon visual inspection I left a vent line dissconected than runs to the filler neck. Iam going to drop tank later for the second time this week, I live in michigan with no garage so I work in the driveway in snow and really dont want to do it a third time any input would be much appreciated
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Sublime181277@gmail.com
December 20, 2012.



The next time you have no fuel pressure, check for spark during cranking. A loss of spark AND fuel pressure is way more common than a loss of just one of them.


Caradiodoc
Dec 20, 2012.
I do have spark I squirted starting fluid in motor and it will run then plus I checked preasure on rail and it is 0


Dandy. Next, check if you have a separate fuel pump relay. If you do, swap it with one of the other ones like it. The AC compressor relay is a good one to use. If your pump runs on the automatic shutdown (ASD) relay, don't worry about that because the ignition coil(s) are powered by it too.

The fuel pump relay, (and ASD relay) only turn on for one second after you turn on the ignition switch and that can be hard to hear but it will give the appearance of having good fuel pressure. It turns on again during engine cranking. Instead of trying to troubleshoot the system while a helper is cranking the engine, simply bypass the fuel pump relay with a stretched-out paper clip or piece of wire. Connect terminals 30 and 87 in the relay's socket. That will allow you to test for voltage all the way back to the pump without even having to turn on the ignition switch.

If you find the fuel pump is locked up, another new one is likely to do the same thing. Chrysler pumps are built to very close clearances to make them a lot quieter than those of some other car brands, but the impellers can become clogged with microscopic debris. You'll go through four or five pumps before one keeps working. To prevent that, have the tank steam-cleaned at a radiator repair shop. The clue to that is to measure the resistance of the motor circuit. If you have continuity, you know the motor and the wiring to it are okay, and the impeller is locked. You can do that test right at the relay socket too. One terminal, 30 or 87 will have constant 12 volts. It's the other one that should read very low resistance to ground.


Caradiodoc
Dec 20, 2012.