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Fuel Pump Diagnosis Assistance (long)

Discussion in 'The Garage' started by okie k5, Mar 2, 2006.

  1. okie k5

    okie k5 Registered Member

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    Hey Guys quick question for you guys. I am looking for a gut check on my diagnosis. Quick background on my issue. I was going to work two days ago and my truck died. I was able to get it to clear the road by pumping the accelerator. Cleared the road and it quit running altogether. Got it towed home, AAA is the bomb, and started with the cheapest and easiest thing today: Fuel Filter. I believe the original fuel filter was on it, has GM factory markings and it was major dirty. It looked like all the little gremlins in my truck were using the fuel filter to take their dueces in. Anyway put new fuel filter in and the pump, as it did after bringing it home, made noise and shuts off whenever you turn the key to on. The new fuel filter now allows the truck to idle but very roughly, it sounds like it is not getting enough go go juice. The truck runs pretty well a little off idle, but misses at WOT. Removed new fuel filter and blew through it and it was not blocked. Put the fuel line from the fuel pump in a big glass jar and energized it. The fuel pump ran for 3 to 4 seconds putting out a full stream, but not a lot of pressure and then shut off. I don't think that the fuel pump should shut off unless it reaches a certain pressure, but I don't know for sure hence the post. SO I think I need a fuel pump anyone disagree?
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    the fuel pump only runs for a few seconds to build up some pressure in the system. Have you run any fuel injector cleaner through it? The only way to be sure is you need to check the fuel pressure while the truck is running
     
  3. okie k5

    okie k5 Registered Member

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    I was under the impression that the fuel pump ran until there was an x amount of pressure in the system so you are saying that is not true?
     
  4. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i don't think it is becaue i replaced my fuel filter one time and truned the key on to pressurize it and it leaked but only for a few seconds. Have you checked to see if you have any codes stored?
     
  5. okie k5

    okie k5 Registered Member

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    Don't have anything on the check engine light at all. It doesn't light up except during the self diagnostic period right after start up then goes dark. I didn't think you could check codes unless the check engine light is on am I wrong?
     
  6. 1979jimmy350

    1979jimmy350 1/2 ton status

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    you can check codes any time. Jumper the the two terminals and count the flashes you should have a code 12 flash 3 times then any codes you have will flash
     

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