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wont run unless you have a test light touching neg. side of coil.

Discussion in 'The Hokey Ass Message Board' started by BISHOP, Oct 30, 2011.

  1. BISHOP
    Joined: Jul 16, 2006
    Posts: 2,571

    BISHOP
    Member

    I was at a friends shop yesterday, and never seen this before. If you try to crank the engine, it will not run unless you have a test light touching the neg side of the coil.

    If its running with the test light, and you take the test light off, it will die.

    Its a v8 with electronic ign.

    Whats going on here.
     
  2. Abomb
    Joined: Oct 14, 2006
    Posts: 1,659

    Abomb
    Member

    You are basically adding a ground with the test light, so is the actual wire on the neg. coil post good ???
     
  3. BISHOP
    Joined: Jul 16, 2006
    Posts: 2,571

    BISHOP
    Member

    Here is the weird part. Tried two different new coils, same result.

    Tried to run a straight wire off the neg post to ground, would not run

    Tried a ballast resister, would not run.

    Test light, runs.

    Ohm meter to see what the test light was pulling, 10 ohm, get 10 ohm resister, wont run

    Back to test light, runs.
     
  4. WDobos
    Joined: Jan 7, 2007
    Posts: 234

    WDobos
    Member

    Ground to engine is no good. Put a good ground to the engine block and I'll bet it runs.
     

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 55,934

    squirrel
    Member

    I wonder how the starter works, if there's no ground to the engine?

    There's not enough info about what it is you're working on, to try to figure out what's wrong.
     
  6. Just wire the test light to it then!!
     
  7. 9310alloy
    Joined: Nov 16, 2007
    Posts: 72

    9310alloy
    Member

    Like Abomb said...you lost your ground...circuit going thru the filament of the lamp.Wire broken , distributor not making good contact to the block , block lost its grond strap/wire to frame/firewall. Missing that part of the circuit....
     
  8. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,534

    50dodge4x4
    Member

    What brand of electronic ignition are you using? I'm betting you need to ground the electronic ignition module/box. If it was a points style ignition, I'd say replace the condenser or ground the dist. Gene
     
  9. BISHOP
    Joined: Jul 16, 2006
    Posts: 2,571

    BISHOP
    Member

    I understand what your saying about the ground, but we run a ground straight to the battery and it would not run. Take the ground wire off, hook the light back up, she busts right off.
     
  10. bobwop
    Joined: Jan 13, 2008
    Posts: 6,115

    bobwop
    Member
    from Arley, AL

    halloween related?
     
  11. tooljunkie
    Joined: Oct 18, 2010
    Posts: 209

    tooljunkie
    Member
    from manitoba

    ok,battery to positive side of coil,trigger/ignition module /points on negative side of coil?what flavour of engine/ignition system?
    cannot hazard a guess at anything til we know what we are dealing with.
     
  12. mace69
    Joined: Apr 11, 2010
    Posts: 153

    mace69
    Member
    from mass

    Do a voltage drop test to the engine. I suspect wdobos is right.
     
  13. BISHOP
    Joined: Jul 16, 2006
    Posts: 2,571

    BISHOP
    Member

    Painless brand, works just like the pertronics magnetic pick up.
     
  14. BISHOP
    Joined: Jul 16, 2006
    Posts: 2,571

    BISHOP
    Member

    I will go back over there tomorrow, I will have better details and follow up what happens.
     
  15. TANNERGANG
    Joined: Jan 18, 2011
    Posts: 1,277

    TANNERGANG
    BANNED
    from alabama

    Look at it in a positive way...with the test light hooked up......(1) Your riding...(2) you'll always have a light so you can see at night...........
     

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