Fuel Pump Check Valve (Again)


rjeffery
02-10-2009, 09:43 AM
Does anyone know if there is a way to fix a bad fuel pump check valve without having to replace the entire pump (running solvent/cleaner in gas, remove and clean pump, ect)? I have fast fuel pressure leak-off after shut down. I replaced my fuel pump 2 years ago for the same problem (with Delphi pump). Thanks.

j cAT
02-10-2009, 10:10 AM
Does anyone know if there is a way to fix a bad fuel pump check valve without having to replace the entire pump (running solvent/cleaner in gas, remove and clean pump, ect)? I have fast fuel pressure leak-off after shut down. I replaced my fuel pump 2 years ago for the same problem (with Delphi pump). Thanks.


the injectors could be leaking...does it smoke on start up ?
what pressures are you getting ?

what is the engine doing ?

MT-2500
02-10-2009, 10:14 AM
Does anyone know if there is a way to fix a bad fuel pump check valve without having to replace the entire pump (running solvent/cleaner in gas, remove and clean pump, ect)? I have fast fuel pressure leak-off after shut down. I replaced my fuel pump 2 years ago for the same problem (with Delphi pump). Thanks.

What year and truck and engine?
First thing check the system to find out where the leak off/down is.
Many places it can leak off.

For a fuel pump leak off test hook a fuel pressur gauge direct onto the inline at the fuel filter.
Prime fuel pump up to running pressure and watch for leak back.
Does it leak off there?

rjeffery
02-10-2009, 12:26 PM
the injectors could be leaking...does it smoke on start up ?
what pressures are you getting ?

what is the engine doing ?

Engine does not smoke on start up and runs fine once started. Engine idleing about 55 psi. Key on, engine off spikes to 60 or so then bleeds off. Engine has trouble starting on 1st crank due to no fuel pressure, will start on 2nd crank.

rjeffery
02-10-2009, 12:37 PM
What year and truck and engine?
First thing check the system to find out where the leak off/down is.
Many places it can leak off.

For a fuel pump leak off test hook a fuel pressur gauge direct onto the inline at the fuel filter.
Prime fuel pump up to running pressure and watch for leak back.
Does it leak off there?

2002 4.8L 1500 Silverado ext cab (other specifics in sig). I will try to get the gauge on the fuel filter later this week. FYI, I did change the fuel filter just before this started happening, maybe I need to check those fittings...

j cAT
02-10-2009, 01:56 PM
Engine does not smoke on start up and runs fine once started. Engine idleing about 55 psi. Key on, engine off spikes to 60 or so then bleeds off. Engine has trouble starting on 1st crank due to no fuel pressure, will start on 2nd crank.


you say no fuel pressure on first crank....if you have no pressure this may be electrical...the fuel pump relay,the fuel pump ground ,and insuring that the fuel pump has 12volts going to it when key is at ignition on position...the fuel pump ground is at the fuel rail next to tank....

the fuel pressures of 55-60psi are normal...it should hold the pressure for 10 minuites or so ....

if you have no DTC failure codes the ECT can cause a cold start problem...the injectors may not be commanded to stay on long enough to give the engine the proper amount of fuel ,,if the ECT sensor reports that the engine is warm...

rjeffery
02-15-2009, 10:37 PM
Ok, I checked the fuel filter and it is tight. Fuel pump runs for a few seconds when ignition is first turned on so I don't think it's electrical. Still have a rapid leak off after fuel pump shuts off, wasn't able to connect my gauge at the filter b/c I don't have the right fittings. So, back to my original question, is there some sort of solvent/cleaner I can put in the tank to clear up a stuck check valve, or do I just need to pony up the $ for a new pump?

Thanks.

j cAT
02-16-2009, 11:05 AM
Ok, I checked the fuel filter and it is tight. Fuel pump runs for a few seconds when ignition is first turned on so I don't think it's electrical. Still have a rapid leak off after fuel pump shuts off, wasn't able to connect my gauge at the filter b/c I don't have the right fittings. So, back to my original question, is there some sort of solvent/cleaner I can put in the tank to clear up a stuck check valve, or do I just need to pony up the $ for a new pump?

Thanks.


so once again ,,,,what is the fuel pressure when key is in the ignition position for the first 2 sec....? IN PSI......

THE vacuum line to the fuel regulator ,,,did you check for fuel residue...the diaphram splitting causes this...

when cranking can you see the fuel pressure pulsing as the engine rotates and does it hold pressure with in the correct range ?

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