99 GMC burb no start

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by wrongwaywillie13, Dec 11, 2013.

  1. wrongwaywillie13

    wrongwaywillie13 New Member

    I've read several thread around the net, but none seem to be or solve my problem.

    the engine cranks over but doesn't start, a few days before hand the truck was hard starting, but only after sitting over night. if I started it and went to the store, it would start on the first crank.
    yesterday it wouldn't fire at all.

    I have about 55 psi with ign. on, 60 when cranking.
    took fuel sample from fuel line and it looks ok.
    checked for spark with screw drive to master cyl. nice blue spark.
    tried spraying started fluid in the air intake at the filter(no filter) no fire
    tried spraying at the PVC hose right near the throttle body, still no fire.

    were to go from here IDK
  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    my guess this is the 5.7 L engine . you need 60-65 psi key on engine off. also the pressure should hold.

    pull some plugs see if fouled. then disconnect maf check for engine start. also check the ECT resistance and the connector. if the ect is open too high on resistance this will occur also.

    with the engine cranking see if the injectors are pulsing.
  3. wrongwaywillie13

    wrongwaywillie13 New Member

    sorry , yes the 5.7.

    what is the ECT ?

    how do I check injector pulse?


  4. j cat

    j cat Epic Member 5+ Years 1000 Posts

    with the pressure gauge on the fuel rail port you see what the pressure is then when cranking the gauge should pulse ..drop down then up..

    the ECT is the engine coolant temp sensor these go bad when this old..many have issues that they open then the computer thinks its 40 below zero and the engine will not start..
  5. wrongwaywillie13

    wrongwaywillie13 New Member

    thanks, I cleaned the plugs a it seemed to want to start but wouldn't. I'll try checking that tomorrow.
  6. j cat

    j cat Epic Member 5+ Years 1000 Posts

    if the plugs are fouled and black this may be the ECT or the wiring and connector to it
  7. wrongwaywillie13

    wrongwaywillie13 New Member

    the plugs were wet with the carb cleaner I sprayed in the PVC. I cleaned them with starting fluid and burned them dry , cleaned with a piece 400 sand paper. still wouldn't start. check fire at #1, nothing, check #2 good. then I noticed a chaff in the coil wire, pulled it off to temporary tape it up, and the term pulled off in the coil. I am going to get plugs and wires today. will update afterwards.

    again thanks for the help.
  8. j cat

    j cat Epic Member 5+ Years 1000 Posts

    only use throttle body cleaner . the carb cleaner will damage the non metal components esp. the electricals.
  9. wrongwaywillie13

    wrongwaywillie13 New Member

    ok. replaced the coil wire. still won't start.

    pulled the plugs and they are wet and smell like gas, check spark with the plug up on top of motor, cyl 1 and 3 spark is good, didn't want to break the wire holder on the other cyl.

    also key on I get 60 psi til the pump shut off then its 55, when I crank it it jumps back to 60.
  10. j cat

    j cat Epic Member 5+ Years 1000 Posts

    so what about my ECT troubleshooting suggestion ?

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