2002 GMC Sierra No go

2002 GMC SIERRA
168,000 MILES • V8 • 2WD • AUTOMATIC
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CSM1992
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I have a '02 Sierra 1500HD (6.0l V8) that won't start. Over the last 6-8 months it has occasionally stumbled while at highway speed (set code for "primary fuel circuit failure"). Three months ago I changed the fuel filter and the fuel pump relay and the problem seemed better even though it continued to set the code. The engine stalled completely while at speed last week but started right back up and ran normally until it failed to start on Friday. I took off the fuel filter, dumped it out and found a goodly amount of fine black "silt" in the gas. Turned on the ignition key 4 times while the fuel line was disconnected and got 3 brief squirts of gas...nothing on the 4th. I think it is fuel pump and another tech thinks it is the computer. Both parts are expensive and I would like your 2 cents- would you lean towards the fuel pump or the computer?
Oct 12, 2009 at 11:38 AM
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RACEFAN966
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Before I would lean in either direction I would need to know what the fuel pressure is. Also would need to know if there is spark.
Oct 12, 2009 at 2:14 PM
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CSM1992
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Spark yes....I don't have a fuel pressure.
Oct 12, 2009 at 3:11 PM
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RACEFAN966
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Ok without knowing the fuel pressure it is hard to say it could be the fuel pump (most likely) or the wire harness to the fuel pump (have replaced many). Now the fuel pressure should be 59-66 psi at the test port on the injection rail unless you truck has the CNG engine then pressure is much higher. So you realy need to test fuel pressure so I can give you an accurate answer.
Oct 13, 2009 at 9:56 AM
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CSM1992
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Right now it has 0 fuel pressure. I will check wire harness and replace fuel pump and see what happens. It seems to me that the pump is getting at least some signal from the pcm and the stream of gas from the open fuel line was pretty weak ---nowhere near 50 psi. My guess is that somewhere along the line the gas was contaminated and the strainer is clogged up. We'll see when I drop the tank.
Oct 13, 2009 at 10:22 AM
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RACEFAN966
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OK that sound good. It sounds like the fuel pump went bad. Let me know how it goes.
Oct 14, 2009 at 9:59 AM
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CSM1992
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It was the fuel pump. The strainer of the old pump was very "rusty" in appearance.
Oct 17, 2009 at 7:43 AM
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RACEFAN966
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So is it fixed? If so then great glad to hear it. If you have anymore problems or questions please just ask. Now just for your own knowledge, try not to run below 1/4 tank as the pump being in the fuel is what helps keep it cool and also change the fuel filter about once a year and your new pump will last years to come. Thanks again and have a great day.
Oct 17, 2009 at 8:42 AM