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TPI igntion problem Need Help ASAP

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hossbaby50, Sep 27, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    I am having ignition problems with my TPI setup. I need help ASAP, I need to get this truck on the road today if possible.

    I pulled my distributor to replace my pickup coil and my reluctor ring (had a small crack). I marked everything when I pulled it out. It still didn't seem to want to drop in in the same place. So I manuallly found TDC and set the distributor. (I found TDC on the balancer and with a spark plug gauge)

    I start the truck and timed it to 8* BTDC. The motor runs fine as long as the timing circuit is disconnected (like when you time the motor) When I turn the truck off and reconnect the circuit and start the truck it runs horribly and then dies. I can't figure out WTF is going on.

    I replaced my module, ECM, and EST but none of it helped any. I am not 100% sure my spare EST is good but I know that the module and ECM are good.

    I went looking for loose wires and things but I am at a lose. I can't figure out anything to get this thing to run right.

    Why would the motor idle fine with the computer timing disconnected and not with it connected. It ran perfectly before.

    Thanks
    Harley

    P.S. The setup is a 88 MAF TPI on a stockish 350. Painless harness.
     
  2. BobK

    BobK 1/2 ton status

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    Just to clarify,You disconnected the brown wire at the dist.when you timed it,correct?
    Disconnecting that wire will create a code so after you've timed it disconnect the battery for 5 min. then try and restart.
     
  3. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Do you have a code?
     
  4. Hossbaby50

    Hossbaby50 3/4 ton status

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    I disconnected the timing wire. Timed it to 6-8* BTDC. Then I turned the truck off. Connected the wire again and the truck will hardly run at all. It starts for a few seconds and starts sputtering then dies. Moving the dist doesn't seem to help much.

    With the wire disconnect the truck runs fine. Connect it and it won't stay running

    I also double checked my TPS reading (.542)

    The only code I get is #42 when the timing wire is disconnected (this is normal when the wire is disconnected). When it is connected it has no codes (or won't run long enough to register any)

    I am totally lost.
     
  5. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    Timed it to 6-8* BTDC.

    [/ QUOTE ]
    As I recall, the spec is for zero degrees.

    The tan/black wire that you disconnect for setting the timing connects between the ECM and the ignition module in the distributor. However, the data to the ignition module is created based on input from the spark control module. A problem with the spark control module, or a bad/loose ground somewhere in the circuit could cause the ECM to spew out lots of wrong data to the ignition module. Check those really well. The brown wire from the spark control module and the black/red wire from the ignition module should both be grounded.
     

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