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5.3 loosing power (no power)

Discussion in 'Chevy Trucks' started by DJ Contracting, Mar 13, 2010.

  1. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    I was on the highway today (70 mph) and raining, anyway the truck loss power and I had to pull over...I shut the truck off for a couple of minutes, restarted the truck and was on my way for about 10 miles then it did it again, and again and again. When I got to where I was going I had the fuel filter changed (that's what it acted like). It didn't help as I was on my way home it started all over again. Now I have a truck that won't get out of it's own way.

    This is what I had checked
    1.Fuel filter replaced (was not able to have fuel pres. checked)
    2.Check for codes and found O2's codes (expected)
    3.Test drove with a scan tool to watch activity showed nothing abnormal.
    #3 leads me to believe that maybe it could be a mass airflow sensor as sometimes they will not leave any codes or show anything abnormal. any help would be appreciated Thanks Joe
     
  2. Sydenstricker Landscaping

    Sydenstricker Landscaping PlowSite Veteran
    Messages: 3,882

    If you suspect mass air flow, pull it out and clean it with some good MAF cleaner. I recommend the stuff by CRC. I would next have the fuel pressure checked while driving it. Im willing to bet that you have a weak fuel pump and the engine is starving for fuel, causing a lean condition and that could be throwing the O2 codes. When my fuel pump was on its way out, the truck had no testes, and was throwing all kinds of O2 codes. Turned out to be the fuel pump. If it is, replace the pressure regulator on the fuel rail as well
     
  3. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    What seem strange is when I shut off the truck and let it set for a couple of minutes it seems to run good for about ten miles or so, but yes I'll have the fuel pressure checked and clean the sensor.
     
  4. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    It sounds like the fuel pump can't keep up or something.
     
  5. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Yeah this might be it's second one, the truck has 128,000 mile on it and I put one in it about fifty thousand ago because of the sending unit we'll see what the fuel pressure reads on Monday
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Don't bother doing anything until you get a FP gauge on it and drive it. As I believe you'll discover that the pressure is dropping off. It's also not unheard of for a brief "cooling period" to bring a dying pump back to life briefly.
     
  7. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    So how much fuel pressure should I be looking for ?
     
  8. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Well I ran a fuel pressure test and at Idle it has 45 psi and going down the road it will maintain 45 psi however during WOT it drops down to 20 psi so now I'll be putting in a new fuel pump/sending unit tomorrow :cry:
     
  9. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Do it the easy way, and lift the bed to access the fuel pump. Be glad that it didn't leave you stranded. Usually a dead fuel pump involves a wrecker bill.
     
  10. ahoron

    ahoron Senior Member
    from here
    Messages: 422

    Get a factory replacement not autozone junk. Also replace the electrical connector on the unit. Should come with the new wiring
     
  11. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Yeah I know i did everything I could to make this 200 mile round trip it was very stressful

    I had replaced the unit in Oct. of 07 with a Advance auto one now I have been on-line looking for one. I found some on ebay however I'm leery because the are selling them for under $100.00 shipped. I did find one at Carquest for $220.00 my cost through my business account.
     
  12. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    x2. I just replaced the fuel pump on my Tahoe. New GM pump was just about the same price as a Carter unit from Napa. It included the new pigtail.
     
  13. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    The one I bought three years ago had the new pigtail so that has been changed already
     
  14. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    The new pump (GM) will likely have a new connector style. The latest one is a very robust electrical connection. There's a good chance you will find evidence of overheating on the pigtail/sending unit.
     
  15. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Some of you say to remove the bed but when I replaced it the last time I removed the front removed the heat shield and loosened up the rear strap enough to lower the front of the tank and replaced the unit all with a broken left thumb. It took me about two hours and I blame the thumb on that
     
  16. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Sorry I'm on my phone that was supposed to read remove the front strap
     
  17. Sydenstricker Landscaping

    Sydenstricker Landscaping PlowSite Veteran
    Messages: 3,882

    Napa carries the Delphi pump, which is the GM oem one. Little more pricey, but 100x better than the autozone junk. I highly highly recommend doing the fuel pressure regulator too. Those can be faulty and cause premature failure of the pump. It is extra $$$, but it is good insurance to have everything last longer this time around
     
  18. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Went I was looking for a pump for the Tahoe, Napa indeed had the Delphi pump. But it was the pump only, no sending unit. I needed the entire module, because one of the electrical pins corroded, overheated, then caused the pump to fail. Napa had a Carter assy, but not Delphi. So I went to the GM dealer. When I put it all back together, I liberally slobbered everything will Fluid Film.
     
  19. t-sig

    t-sig Senior Member
    from 607
    Messages: 121

    DJ,

    If you do drop the tank completely, or remove the bed, you may want to check/change the brakeline going from the block under the cab to the rear axle. It is alot easier to change when you have some extra room. I don't know if Michigan uses salt on the roads, but in NY, a truck with that much mileage doesn't have too many stock brakelines that aren't rotten.
     
  20. DJ Contracting

    DJ Contracting PlowSite.com Addict
    Messages: 1,392

    Of coarse I had to check this after I replaced it, anyway I took some pictures while the bed was sitting on the tires and rear bumper.
    Now it has a new fuel filter, fuel pump, and sending unit,
    The new pump reads 60 psi at start up then goes down to 53 psi at idle, at cruising speed ( anywhere from city driving 70 mph highway) it maintains 55 psi if I gun it to pass the pressure would rise up to about 57-58 psi. Now do you think that if I replace my fuel pressure regulator I might be able to maintain 60 psi all the time?

    Oh I removed (broke) the ground bolt for the ground strap, this also had a ground wire coming out of the fuel pump wire harness, I believe for the fuel system because it would not restart until I reattached the grounds just FYI.

    99 Fuel pump 1.jpg

    99 Fuel pump 2.jpg

    99 fuel pump 3.jpg

    99 Fuel Pump 4.jpg
     
    Last edited: Mar 15, 2010