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NO Spark...... TBI 88 GMC 5.7 350

Discussion in 'TBI & EFI Conversions' started by mhelms83, Jul 17, 2012.

  1. mhelms83

    mhelms83 Member

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    OK, so im ready to crack!
    I have a 1988 GMC Suburban Sierra Classic. It has a 5.7 350 TBI. I have no spark to plugs. I just replaced the following (again): Ignition Module, Coil Pack, pick-up coil, Dist. Cap, and rotor button. I still have no spark. please help before I loose it and send this burb to an early grave.
    BTW, sorry if this is posted in the wrong place. Im new to this :)
     
    Last edited by a moderator: Jul 20, 2012
  2. oneluckypops

    oneluckypops Full Access Member

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    Not to be to big of a smart ass especially since your new here, BUT. It almost seems as if you need to start doing some diagnostics instead of just changing parts hoping for the best.

    There are several wiring diagrams on here already for a TBI system. I would start there read the diagrams and start checking your truck for power. Could be as simple as a blown ECM fuse or a broken wire. I will see if I can find 1 for you and post it in here
     
  3. HotRodPC

    HotRodPC Administrator Staff Member

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    Are you getting 12 volts to the 10 guage ignition wire at the dizzy cap? Try running a hot wire from battery terminal positive to the IGN side of the dizzy cap, and try to fire it up, if it starts, then check IGN fuses, if good, start tracing that hot wire. Remember, if it starts, to shut it off, you'll have to disconnect the hot wire at the battery to dizzy cap.

    BTW, Welcome to GMSB.
     
  4. HotRodPC

    HotRodPC Administrator Staff Member

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    OH wait, TBI Dizzy. Not as easy as HEI. But, yep, I'd still check for power, and check fuses.
     
  5. oneluckypops

    oneluckypops Full Access Member

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    Where are all the TBI wiring diagrams at?
     
  6. Jims86

    Jims86 Full Access Member

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  7. mhelms83

    mhelms83 Member

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    wow, thanks for the quick response guys. Yes i did test and i have power at the fuse box(and all the fuses are fine) , Ignition mod, and coil. i also made sure the ECU is getting power. I also tested the old pickup coil and it was bad (thats why i put a new one in)

    I had the same problem about 4 moths ago and it was the coil pack and ignition module so i just exchanged them and put new ones in.
     
  8. Jims86

    Jims86 Full Access Member

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    Pull the coil wire off, and stick a bolt in it, and put it next to a ground, like a manifold bolt, and have someone cycle the key to the on position, where the fuel pump primes.
    You should see a quick single spark, then have them crank it and see what happens.
    It is possible to get bad new parts.
    Also, unplug the 2 wire harness from the dist to the coil, and check the black ground wire for continuity, thats what fires the coil. Also check the dist for good ground.
     
    Last edited: Jul 17, 2012
  9. 89Suburban

    89Suburban Full Access Member

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  10. oneluckypops

    oneluckypops Full Access Member

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    ok good alot of people dont sorry for assuming
     
  11. mhelms83

    mhelms83 Member

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    ok, so i tested the new ignition coil and its bad. thanks advanced auto...
    went to napa and got a new one but now the battery's too low to know if it'll crank up. waiting on a friend to give me a jump and we'll see if that fixed it. fingers crossed!

    [​IMG]
     

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  12. 89Suburban

    89Suburban Full Access Member

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    Damn nice lookin Burb hoss!!!
     
  13. Jims86

    Jims86 Full Access Member

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    X2!
    As far as the coil, and other ignition parts, its worth the cost to get AC Delco.
     
  14. mhelms83

    mhelms83 Member

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    well i got a jump its still not running :( I did notice the white wire from the starter solenoid was looking a bit rough so I put a new end on it, but that didnt work either.
    any other suggestions?
     
  15. Jims86

    Jims86 Full Access Member

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    Pop your air cleaner off, and see if the fuel injectors are spraying fuel in while somebody cranks it for you. If it does, that means the ecm IS getting a reference pulse from the ignition module.
    I would get under the dis cap too to make sure the pickup coil didnt come unplugged.
     

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