1994 GMC Sierra C1500 NO SPARK !

Discussion in 'GMC Truck Forum' started by frunge, Dec 10, 2009.

  1. frunge

    frunge Member

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    I've got a 94 GMC with the 4.3 Vortec...Driving along and it dies...Fuel pump OK gas in tank..Check for spark..none...My buddy tows it home for me and the next morning,it fires right up runs for few minutes and dies..No spark..Put a new coil on it..Started right up and died..Again no spark...Any Advice ?? I'm no stranger to a wrench,but no scan tools,etc...Thanks
     
  2. bradrhale

    bradrhale Senior Member

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    94 with a vortec?? cool.

    trace the lack of spark back. none at the plugs. how about the rotor and cap?? good?? the coil is new so that can be skipped. still no fire?? your pickup under the dizzy may be malfunctioning and not closing the loop on the coil permitting fire. ignition is fairly simple to diagnose as the system doesnt have that many components and all are inline. keep tracking back up the line until you find fire.
     
  3. frunge

    frunge Member

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    OK..No spark to the plugs..Cap and rotor LOOKED ok...I'll investigate further tomorrow...Thanks !!
     
  4. 1500cheyenne96

    1500cheyenne96 Senior Member

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    Do those still have a pick up coil under the cap? not to sure if they do or don't but i know on a HEI that is a cause of no sparky sparky if it does check that
     
  5. bradrhale

    bradrhale Senior Member

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    opportune word there is looked. i am not going against your visual judgement so dont get me wrong. verfiy that you have no spark with more than a visual test. take that screwdriver and stick it in that coil wire and get close to the block with the length of the driver. turn the engine over and see if you see spark. no spark?? than you need to look further back. you have spark there?? cap and rotor is your problem.
     
  6. frunge

    frunge Member

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    Once again...Thanks !!..I'm determined to turn 200,000 on this thing..Currently has 194,650..Does not use or leak oil, no rust,etc...I just love the darn ol girl !
     
  7. frunge

    frunge Member

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    Traced it to the red/white wire leading from the coil to the distributor ignition module. Yanked on the wire and got spark..Is this connector wire a dealer only item ??..Parts dept at my GM dealer closed on Saturdays....
     
  8. bradrhale

    bradrhale Senior Member

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    im guessing you are talking about the end closer to the ignition control module under the dizzy cap?? the wire on the coil side should have posts. where exactly are you talking about?? if the wire is broken at the module, you might want to buy a new one. they do not cost that much. if the connector itself is messed up, you might have a bit of a problem locating one. since this is not what i would call a voltage sensitive wire, you may be able to properly splice it together. this wire is no more than just a grounding wire telling the coil to fire.
     
  9. crabtruck

    crabtruck Senior Member

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  10. frunge

    frunge Member

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    Many thanks to all who provided me advice...It turned out to be the red/white wire leading from the coil to the ignintion module..I crimped the connectors a little tighter and she fired right up....Back on track for 200K.
     

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