Engine cranks but will not start

2Valve2Valve Posts: 146 Baller
The wife wanted to go for a moonlight cruise the other night but we were low on gas. I chanced it but ended running out. Got towed in and filled the tank but now it won’t start.
2002 PCM 5.7 engine with 850 hours. Throttle body fuel injection. Engine cranks over fine.

I verified fuel pressure up to the throttle body by removing the high pressure line from the FCC and cranking the motor where a strong spray of fuel occurs.
But the twin injectors won’t spray no matter what.
I checked all three engine fuses with an ohmmeter. None are blown. Lastly, I switched off the battery, thinking maybe some error was generated by the ECM. Switched on the battery and still won’t start.
What could have happened?
Thanks, 2valve



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Comments

  • S1PittsS1Pitts Posts: 156 Baller
    edited June 2018
    Engine cover lifted - can you hear the electric fuel pump build pressure and then cut out when turning on the key? It should cycle each time you turn on the key. It might still be vapor locked?
    Have you checked the emergency tether switch? they seem to fail at the oddest times. Pull off tether and cycle plunger several times and check to make sure the clip depresses the plunger adequately to activate the switch.
    Have you checked for spark on the ignition system? - My spark died when one of two relays mounted on ECM mounting plate failed.
    Hope this helps
  • Ski_DadSki_Dad Posts: 339 Baller
    have you changed the fuel filter ? - it might have a bunch of junk in it from the bottom of the tank.
  • BraceMakerBraceMaker Posts: 3,374 Mega Baller
    Do you have a timing light?
  • oldjeepoldjeep Posts: 3,351 Mega Baller
    Does the fuel line have a bleeder? Could just be air locked.
    Chuck P
    Not a mechanic but I play one at home
  • 2Valve2Valve Posts: 146 Baller
    @Mitzysman
    Yes sir. Changed it in the fall. I even took it out of the FCC to check any differences.
  • 2Valve2Valve Posts: 146 Baller
    @BraceMaker
    I have a timing light. What are you thinking?
  • 2Valve2Valve Posts: 146 Baller
    @oldjeep
    There’s a bleeder on the FCC. I bled that for a second while cranking and plenty of fuel exited.
  • 2Valve2Valve Posts: 146 Baller
    @S1Pitts
    Yes sir. Fuel pressure builds with key on then stops and resumes again while engine is cranking. Tether switch is good. Power to all gauges with key on. I haven’t checked spark.
    I’ll check the relays but the timing of just running out of fuel is too weird. The only ‘visual’ issue is no spray from the injectors while cranking the motor.
  • 2Valve2Valve Posts: 146 Baller
    I’m going to swap the relays around to see if that resolves it.
  • BraceMakerBraceMaker Posts: 3,374 Mega Baller
    edited June 2018
    Toss it on a wire and make sure you are getting a spark. The spray is usually triggered by the ignition module from a pick up coil on the distributor. No blinkey blinkey and you want to pop the dist cap and disconnect pickup coil and test its resistance. If good suspect ICM.

    This will give you the visual no spray with a primed system. Injector can be fired by a 9V battery but I would do that off the boat.
  • 2Valve2Valve Posts: 146 Baller
    I think I got it. Swapped the two relays and now it runs. The PCM manual says I should have three but I only gots two. I’m guessing one is ignition and one is fuel??
    The both are Hella’s, 12193611.
    Thanks everyone fir your help. Nothing worse than being my turn to pull the club and boat is down.
  • 2Valve2Valve Posts: 146 Baller
    Quick update:
    After swapping the two relays, of which 3 functions are controlled, (fuel, ignition, starter), everything worked. My thought if it was a bad relay, is something would have failed, like the engine not cranking over.
    So I decided to buy new relays anyway and now it won't start again.
    My next course of action is to get a timing light and crank the engine to look for spark (timing light strobe) on any cylinder, verifying that the ignition is triggering. I seem to recall that this PCM, the injectors won't spray if the ignition isn't triggering.
  • DragoDrago Posts: 1,438 Mega Baller
    Does it fire @ all?
    SR SL Judge & Driver (“a driver who is super late on the wheel and is out of sync”)
  • BraceMakerBraceMaker Posts: 3,374 Mega Baller
    @2Valve correct, if you have a voltmeter with Ohms like you mentioned earlier you can also go right to testing the pick up coil.

    The fuel injector circuit is triggered by the ICM on the distributor which uses a pick up coil on the distributor shaft under the rotor. This coil is reading pulses from a disc and should have a certain amount of resistance, so if you undo the clip behind the ICM you can use an ohmmeter to read that, and I believe that should be 500-1000 Ohm but certainly not 0 ohms and certainly not an open circuit. Either would say bad pick up. This is a ~10$ part.

    If that tests good and you don't have spark then you want to check the ICM or you can also check the coil. ICM is about 80-100.

    If you have a can of carb cleaner you can also see if the boat will fire on a few toots of that which would indicate you have spark and no fuel which would usually eliminate the circuitry of the ignition module.

  • BraceMakerBraceMaker Posts: 3,374 Mega Baller
    And goes w/o saying double check your kill switch lanyard which is a "always do first" thing just like the mower deck on a lawn tractor.
    Drago
  • 2Valve2Valve Posts: 146 Baller
    @Drago
    No sir. It just cranks with no hint of firing.
  • 2Valve2Valve Posts: 146 Baller
    @BraceMaker
    Thanks for the info. Appreciate it.
  • eleeskieleeski Posts: 3,784 Infinite Pandas
    A shot of starting fluid addresses things fuel - just to see if the engine will fire.

    You changed the relays and it worked? Then you changed them again and it didn't? The problem started after fuel exhaustion? Weird problem.

    With weird problems, disconnect the battery for a couple minutes. This resets everything electrical.

    Good luck.

    Eric
    Monkstr6100
  • eyepeelereyepeeler Posts: 160 Baller
    I was informed by mechanics to NEVER run your boat out of fuel. The newer electronic fuel pumps are lubricated by the fuel. If you run out of fuel there is a good chance that it could ruin the fuel pump.
    Matt Dillon
  • Monkstr6100Monkstr6100 Posts: 107 Baller
    Check the actual fuel pressure. If it is low it will not trigger the injectors. More than just depressing the shrader type valve on the rail, put a gauge on it.
    THE FAMILY THAT PLAYS TOGETHER, STAYS TOGETHER! TEAM JACHOWICZ
  • thagerthager Posts: 4,388 Mega Baller
    Check the spade connections on back of safety switch. I had similar event. Engine turned but no fire.
    Stir vigorously then leave!
  • 2Valve2Valve Posts: 146 Baller
    @eleeski
    I swapped the two relays and it worked. Then I changed both for new and it didn't. I re-installed the original relays and it still didn't start. I'm looking at the Ignition Control Module now as a possible source.
  • 2Valve2Valve Posts: 146 Baller
    @eyepeeler
    Agreed. I attempted to re-start just once and then we got towed.
    I DID remove the FCC fuel pump and verified that it was good with some bench testing.
  • 2Valve2Valve Posts: 146 Baller
    @Monkstr6100
    Will do. I didn't have all my special tools with me but I'll be back out tomorrow night with my gauges. 30psi is what I expect for a TBI system, (what it was producing last fall)
  • GarGar Posts: 310 Baller
    I helped a friend work on one of these if I remember correctly there is a low pressure pump feeding the pump in the FCC. Maybe it's bad don't know.
  • 2Valve2Valve Posts: 146 Baller
    @Gar
    thanks, but I replaced the low pressure pump last spring. The FCC bowl is filling, so I assume its still good.
  • 2Valve2Valve Posts: 146 Baller
    @BraceMaker
    I verified that the safety switch is good and working properly.
  • BraceMakerBraceMaker Posts: 3,374 Mega Baller
    Good, best luck! I hope its not fuel related, I cannot stand working on the fuel systems of boats.
    2Valve
  • BeastmodeBeastmode Posts: 89 Baller
    I have had same issue on a 94prostar many times. Fuel pump pressurizing but injectors not firing.
    i have unplugged one injector and put a jump wire on injector posts one to ground and the other to a 12v hot(remote starter switch is best)and crank starter and while activating injector and it fires off and starts working. I suspect fuel pump going bad. Causing low prime pressure. Hard to duplicate because it’s random
  • AndreAndre Posts: 1,106 Crazy Baller
    edited June 2018
    @2Valve
    Here's a VERY good guide to troobleshoothing a no spark/no start on a GM 350.
    I have use it on my 94 MC last year and this saturday on a 00 Response lx with same engine as you i beleive.
    Real easy to follow.It use another method for checking pick up coil then the Ohms on page 6.
    http://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/distributor-mounted-icm-tests-6


    Here is what mine looked like last year...
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