Fuel Problem 97 K1500 Suburban

Discussion in 'Performance & Fuel' started by Izone_Dave, Dec 5, 2009.

  1. Izone_Dave

    Izone_Dave New Member

    1997 Subrban K1500 4x4 5.7 Litre - Just spent the day replacing the fuel pump (original symptom - car would run for 1 minute - then fuel pressure drop), only to have similar symptom - pressure good - 50 lbs. upon idle out of gear for as long as you want - put it in gear - pressure drops (not immediately - takes a few seconds) and she stalls - pressure around 20 lbs. - then takes a couple of tries and pressure returns and she runs in park - and so on.

    New parts so far = fuel pump, pickup screen, wire harness, fuel filter.

    Anyone have any ideas for what to do next? Or what to check? I hate to keep throwing parts at it.
  2. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Did you check the return line? Check to see if it is clear. Also make sure you have the right gas cap on.
    Is it throwing any DTC codes?
  3. Izone_Dave

    Izone_Dave New Member

    Didn't check the return line - assumed (I know) that since it will run in park forever, that the lines must be good) no codes - gas cap is correct.

    Side note - fuel system doesn't hold pressure once key turned off - drops to 25 or so - and isn't gong right up to full pressure either - takes 2 or 3 times (turning key on) to come up to pressure and start.

    Truck has been great for years up until now - started dying - it would restart - go 25 feet - die repeat the process. I reasoned that since the fuel pressure (then) was good - then dropped almost right away, that the fuel pump was bad - guess I was wrong - what next?
  4. Chevyboy96

    Chevyboy96 Rockstar 4 Years ROTM Winner 100 Posts

    Can you rev the engine up in Park?
  5. Izone_Dave

    Izone_Dave New Member

    That is affirmative - vehicle behaves perfectly in park.

    Note - have done further investigation - jumping pins 87 and 30 of the fuel pump relay caused the fuel pump to start each time - trip to the parts store - new fuel pump relay - problem solved.
    Last edited: Dec 6, 2009

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