Erratic then no fuel pressure

Tiny
JIMMYP
  • MEMBER
  • 2002 JEEP GRAND CHEROKEE
  • 128,000 MILES
Have a 2002 GC with a 4.0 L. Recently noticed a problem re-starting once it had been driven for a while and then sits for several hours. Plus there was a 'squeaking noise' near the tank that sounded almost like a pump oscillating on/off/on/off. Concerned the fuel pump was going bad, I changed two weeks ago. The noise is still there (maybe gone for a few days). Two days ago after driving two to three miles the Jeep lost power started missing and shut off. After sitting for a while it would restart but repeat this process. I changed the fuel pressure regulator/filter last night and drove around the block. Quit running half way. Finally was able to check the fuel pressure. Around 44 psi with key on - seems to hold but I did not leave in sitting very long. Started and at idle around 54 psi. After three to five minutes as the Jeep reached operating temperature the pressure gauge needle started vibrating very fast between approximately 50 - 55 psi. Soon after the gauge dropped to 40, 30, 20 then to around 0-5 psi, all in about ten seconds. Up until then the Jeep seemed to be running okay, maybe a little rougher idle, but soon after the pressure drop the idle became very rough on it shut off (as expected). Concerned I never really had a bad fuel pump but do now. Could there be something else causing the pump to essentially quit or drop pressure? As noted I changed the regulator/filter and the Jeep did the same thing. Thoughts?
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Thursday, June 7th, 2012 AT 11:49 AM

4 Replies

Tiny
KHLOW2008
  • EXPERT
Seems like you got a bad replacement fuel pump. It seems to be failing after running for some time and I believe that is where you should be looking at. Also replace the fuel pump relay.

Here is a guide to help people check their fuel pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

After engine stalled and when there are no fuel pressure, test the fuel pump operations and check for power supply to the fuel pump. Here is a guide and the wiring diagrams:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what happens.

Cheers
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Thursday, June 7th, 2012 AT 1:19 PM
Tiny
DENTALFITCHIC
  • MEMBER
I had this problem as well it ended up being the fuel pump relay under the hood. FYI, it cost me $34.00 for a new part.
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Thursday, September 20th, 2018 AT 7:46 PM
Tiny
TERRYHIIVALA
  • MEMBER
  • 2002 JEEP GRAND CHEROKEE
  • 110,000 MILES
I pulled fuel pump relay started Jeep until died replaced fuel filter put relay back in no fuel disconnected outgoing line no fuel. Swapped relay no fuel. Any suggestions? It worked before just had a loss of power. Fuel filter was plugged.
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Thursday, September 20th, 2018 AT 7:47 PM (Merged)
Tiny
WRENCHER1
  • EXPERT
No, a fuel filter will not do that, but it will ruin a fuel pump. You need to use a fuel pressure gauge to determine what it is doing now and if the pressure is low, verify power to the pump during cranking.
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Thursday, September 20th, 2018 AT 7:47 PM (Merged)

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