low fuel pressure

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Apr 10, 2010 | 11:20 PM

pete315

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low fuel pressure

I have a 97 Explorer that sometimes feels like it's running out of gas. I got a check engine light on and one of the reasons the computer said was low fuel pressure. question- what would cause low fuel pressure? is it a weak fuel pump or the fuel regulator? how can you test which one it is? I thought fuel pumps either work properly or they don't work at all. Fuel filter was changed about 5,000 miles ago.

Apr 11, 2010 | 01:37 AM

scucci

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If the fuel filter is clean you could have an electrical problem - low voltage at the pump, a bad regulator or a worn out pump. Fuel pressure spec is 30-45 psi. Leak down test- Verify fuel pressure remains within (5 psi) of the maximum fuel pressure for 1 minute after the fuel pump is turned off. Remove vacuum line to pressure regulator with engine running and look for fuel in the line indicating a leaky diaphram, removing the vacuum line should raise pressure about 5 psi. You need an inexpensive fuel pressure gauge to test this.

Apr 11, 2010 | 08:09 AM

shorod

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From: Cedar Rapids, IA

I can't recall ever seeing a "low fuel pressure" diagnostic code. Do you have the exact code number? Are you sure it wasn't a code for low fuel tank pressure (emissions-related) or possibly a lean air-fuel ratio?

The code should be in the format P0123.

-Rod

Apr 11, 2010 | 04:56 PM

Sikdmax

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Definitely replace the fuel filter and see what happens.

Apr 14, 2010 | 05:41 PM

Moto Mel

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From: Chesapeake, Va.

Quote:

Originally Posted by pete315

As you have recently changed the fuel filter and still have low fuel pressure I would suspect that you might have gotten bad gas at a recent fuel stop. Take the filter off and see if any nastiness comes out, if the the filter has a mess of debris in it your pump may be clogged. If not, the pump may have died. Or there may be an electrical problem.