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98 5.7 Fuel Pressure

Discussion in 'Chevy Trucks' started by Crappie Reaper, Feb 27, 2006.

  1. Crappie Reaper

    Crappie Reaper Junior Member
    Messages: 4

    I was driving yesterday morning and my truck just died. It acted like a firing problem, but could not find anything wrong. I went ahead and changed the coil and module because I had a couple of new ones in the garage under the just in case dept. I replaced the fuel pump this last summer and am hoping that the new one hasn't gone out yet. The new one whinned just as loud as my old one (original) did and I got 160k + miles out of it. I pulled the fuel filter and it was just about completely clogged. I replaced it. I stuck a fuel pressure gauge on the fuel line, and turned the key on. I am only getting 14-16 lbs of pressure. I tried resetting the ecm by disconnecting the neg terminal and reconnecting it. Still same reading, 14-16 lbs. The book shows I should be getting between 60 and 66 lbs of pressure.

    Question is, can anyone think of anything OTHER than the fuel pump that could be creating this problem. I hear clicking sounds at the top side of the engine compartment when the key is turned on and after the fuel pump has ceased it's intial startup whirring noise.
    Anyone have a clue, or do I need to start removing the bed now to get ready for a replacement pump?
    Thanks
     
  2. scottL

    scottL PlowSite.com Addict
    Messages: 1,600

    If you have not changed out the fuel pressure regulator - you'll probably have to.

    You need to get pressure of 58+ when key is turned on. After about 10 seonds when the pump reaches presure the psi should drop by no more than 10 psi in 20 minutes. Otherwise, the pump is bad. ( 14-16 punds your pump is dead )

    I had the dealer replace my pump 2 years ago and it was loud. It went out again and the new one is very quite.
     
  3. Crappie Reaper

    Crappie Reaper Junior Member
    Messages: 4

    bosch fuel pump

    I just picked up a Bosch pump from AutoZone with a lifetime warranty on it. There was a mechanic from a local dealership there and told me the same thing about the Pressure Regulator. I can't find a thing in the Chiltons on it. He also said that I could test it with an ohm meter. He suggested that I do it before replacing the pump which I don't look forward to doing. Thanks for your input on it!
     
  4. scottL

    scottL PlowSite.com Addict
    Messages: 1,600

    I have a '97 5.7L. The regulator is under the upper manifold. It's not a hard job it's just time consuming. Beginning to end plan on 3hrs ( I'm more of a tinker ). Simply a lot of little parts, lots of screws. Since you've got more than 75k on the truck I would just replace it. The part was under $20 bucks.

    The testing procedures I found covered numerous components which then helped to identify the regulator. I felt it would take more time to test than to simply replace.
     
  5. Crappie Reaper

    Crappie Reaper Junior Member
    Messages: 4

    Thanks!

    Thanks for the info Scott. Just wanted to let you know, that I did run a pressure regulator test by disconnecting the return line, then sticking a quick connect for a airhose on it to block it off. I turned the key on and still had the same amount of pressure as before. I went ahead and replaced the fuel pump, and then turned on the key. Pressure gauge only showed 14lbs. I thought that I had not fixed my problem. I then, turned it over to start and she fired right up. Guage was showing 60lbs of pressure. So, problem solved for now. Thanks again for your suggestions.
     
  6. Crappie Reaper

    Crappie Reaper Junior Member
    Messages: 4

    Thanks!

    Thanks for the info Scott. Just wanted to let you know, that I did run a pressure regulator test by disconnecting the return line, then sticking a quick connect for a airhose on it to block it off. I turned the key on and still had the same amount of pressure as before. I went ahead and replaced the fuel pump, and then turned on the key. Pressure gauge only showed 14lbs. I thought that I had not fixed my problem. I then, turned it over to start and she fired right up. Guage was showing 60lbs of pressure. So, problem solved for now. Thanks again for your suggestions.
     
  7. MrBigStuff

    MrBigStuff Senior Member
    from Boston
    Messages: 140

    Pump

    I wonder what the pickup sock looks like if the in-line filter was clogged. Sounds like you have junk in the tank and it's clogging the intake sock.

    I'm sure it didn't do the pump any good to be running against that fuel filter restriction either.