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1999 jimmy HELP

Discussion in 'Chevy Trucks' started by milwaukeevtwin, Jan 15, 2009.

  1. milwaukeevtwin

    milwaukeevtwin Senior Member
    Messages: 335

    My service engine light came on earlier in the week and it has a leak in the system. I have to push the pedal to get gas up to it. I installed a new gas cap and it still does it. It acts like it is loosing pressure.
    I went out this morning and it was -15 outside. I had to pump it 8 time to get it started. Where should i start? Any ideal?:dizzy:
  2. Clint S

    Clint S Senior Member
    Messages: 280

    Get is scaned by a good OBD2 scanner. You probably have a gas line leak and are losing pressure
  3. Steve'sZr2

    Steve'sZr2 Member
    Messages: 86

    Have you had your battery tested, have your fuel pressure tested. Should be around 58 psi. Can you hear your fuel pump priming right away? When you say leak, do you see gas leaking or smell it? Could be as simple as a bad fuel filter, or could be the fuel injectors or fuel pump. When is the last time that a tune-up was done? could be bad spark plugs or any other part of the ignition system, The check engine ligth might be for a misfire. If your local autozone or repair shop can't find anything, bring it to a GM dealer and get it scanned by their tech.2 scanner.
  4. milwaukeevtwin

    milwaukeevtwin Senior Member
    Messages: 335


    I had it scanned by Autozone and they said i had a leak in the system. They said to try a new fuel cap. I smell no gas.I have about 5,000 miles on everything, since the tune up. I need to try the fuel filter. I got a feeling, i am loosing pressure somewhere.The battery is brand new, with an alternator that idles at 105 with an output of 165. I also did the big three with 0-out guage wire. Believe me, i have plenty of cranking power. The Jimmy sits outside with my Silverado and the Silverado has a new battery, also and it does not even come close to cranking, like my jimmy. I will try a fuel filter and get back with you Guys. It seems like it only happends when it gets real cold. Thanks, Ron
    Last edited: Jan 15, 2009
  5. Clint S

    Clint S Senior Member
    Messages: 280

    You could have a leak in the sending unit inside the tank causing pressure to bleed down and not physically lose or smell any gas. Rare but just a thought. You need to have your fuel pressure tested to find if it is bleeding down. You could also have a fault relay causing the pump not to prime. The check engine light go out and stay out once cleared, could have been 2 seperate issues showing up at the same time.
  6. JEEP12

    JEEP12 Junior Member
    Messages: 4

    You could have more than one problem. The Service light may have been a result of the gas cap because it is part of the EVAP system. The hard starting may be an unrelated problem. I would check the fuel pressure with a fuel gauge. The pressures should be around 55-60 psi.KOEO(Key on engine off), and watch for fuel pressure drop with KOEO . The pressures should hold steady, If it doesn't it could be fuel regulator, fuel pump, or a fuel injector. If it doesn't hold it would have to crank longer.
  7. LooseLugNutz

    LooseLugNutz Junior Member
    Messages: 14

    you must have at least 54 lbs of pressure for the injector cfi spider poppetts .....my jimmy was hard to/wouldnt start with 50psi ...had to put a new pump even though the old one seemed fine (except for the -4 psi needed).....try putting some fuel directly in the throttle body then quickly put back the intake air tube and try to start....if it starts fine its probably your pump......my would not start with less than 54 psi.......but would run just fine once it was started
  8. festerw

    festerw Senior Member
    Messages: 986

    Easy way to tell if you're just loosing pressure is to cycle the key to on 4 times leaving it in the ON position for about 10 seconds each time. Then turn it to start (don't pump the gas pedal) and see if that helps if it does you indeed are leaking down pressure.