1994 Chevy K1500 5.7 Starting Issue

Discussion in 'Chevy C/K Truck Forum' started by LawnServiceGuy, Oct 19, 2012.

  1. LawnServiceGuy

    LawnServiceGuy New Member

    Hey guys,

    New to the board but have read it several times over the past month. I have a 1994 K1500 5.7 work truck with 215,000 miles. I only drive it roughly 20 miles round trip to run my side lawn business so I would like to keep it solely for that. I have time to try to fix it myself and this has me stumped. I am by no means a mechanic but I want to try to fix it before I do anything else. Here is the deal:

    The truck starts up fine every single morning or afternoon on the first try. I would say it starts 99% of the time; even after driving it and stopping for a while. However, over the past two months, I have gone to a job, reached operating temperature, let it sit for 30 minutes to an hour, and try to start it and it would just crank and not start. It has done this 3 times now. Each time, if I leave the truck overnight, it starts right back up like a new truck the next morning.

    I have tried to self diagnose this as best as possible. Here is what I do know:

    It is getting fuel to the TBI and the injectors are spraying fuel.

    I am getting spark to the 1 and 3 spark plugs.

    I previously thought it was a ignition issue and not getting any spark. I replaced the ignition coil and it still has the problem.

    There are no error codes when its in this condition. I also thought it was a "heat issue" but yesterday, after driving it roughly 1/10 of a mile, it did it again. Like before, it cranked right up this morning. Could it be a compression issue? The truck runs great. Only other symptom would be a "looping idle" where it idles "down" or "skips" at a stop light. It has never died while at a stop light though. Could these symptoms be related? Would the idle problem be air flow related?

    I replaced the fuel pump, fuel pump relay, and fuel filter all within the last 3 months. Any help you can provide will be greatly appreciated.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Welcome to GMTC! The idling down or skipping at a stop light could be an IAC issue.
  3. LawnServiceGuy

    LawnServiceGuy New Member

    Thanks. Could a bad Idle Air control valve contribute to my no start condition?
  4. LawnServiceGuy

    LawnServiceGuy New Member


    Happened again yesterday. Luckily it was in my driveway. Decided to try to unplug the ECM when it was in this condition and see what happens. Unplugged the two connectors for a minute or two, plugged them back in, and the truck started. Started fine several times immediately after. I'm guessing a bad ECM or a wire/sensor is sending an error message?
  5. Chris Miller

    Chris Miller Rockstar 100 Posts

    It definitely can be a bad IAC. My 1994 Suburban was almost impossible to start without putting my foot in it, and it would sputter around at about 500 rpm, blowing black smoke, all sorts of nasty stuff. Turned out the IAC was bad.
  6. SpeedoJosh

    SpeedoJosh New Member

    So, can you actually see fuel spraying when truck is turning and not starting?
  7. LawnServiceGuy

    LawnServiceGuy New Member

    Yes. Someone else has to be trying to start it though.

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