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Confusing Ignition Problem

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Old Jul 18, 2009 | 07:42 PM
  #1  
runway1's Avatar
runway1
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From: CA
Default Confusing Ignition Problem

My son was driving along with an engine that's been humming and running very well and then BAM, it just died. It has a Pertronix II module that we were concerned about and an original '65 dizzy with a crack in the housing.

So, we replaced the whole unit with a Mallory HEI and still have no ignition. We have fuel - pumping along just fine. Compression is about 90 psi - seems low but good enough for ignition – and we have spark at the plugs, although it doesn’t seem very strong.

Compression, fuel and spark. Why no ignition? It doesn’t even seem to baaaarely kick over. It has that turning sound as if you pulled the coil wire. I’m measuring 12v at the coil (12.25v). Could it be that somewhere I have a frayed/loose wire that may somehow be limiting the current flow? Could 12v and a weak current (amps) screw up ignition? Any suggestions?
Old Jul 18, 2009 | 11:26 PM
  #2  
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photocliff
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From: Sandy, Utah
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Wondering if timming chain skipped or ground to engine block is loose?
Old Jul 19, 2009 | 07:55 AM
  #3  
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2+2GT
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Originally Posted by runway1
My son was driving along with an engine that's been humming and running very well and then BAM, it just died. It has a Pertronix II module that we were concerned about and an original '65 dizzy with a crack in the housing.

So, we replaced the whole unit with a Mallory HEI and still have no ignition. We have fuel - pumping along just fine. Compression is about 90 psi - seems low but good enough for ignition – and we have spark at the plugs, although it doesn’t seem very strong.

Compression, fuel and spark. Why no ignition? It doesn’t even seem to baaaarely kick over. It has that turning sound as if you pulled the coil wire. I’m measuring 12v at the coil (12.25v). Could it be that somewhere I have a frayed/loose wire that may somehow be limiting the current flow? Could 12v and a weak current (amps) screw up ignition? Any suggestions?
If you put in a GM HEI and still get no ignition, then the distributor is getting no power. If the engine cranks slowly, that's a starter problem.
Old Jul 19, 2009 | 08:55 AM
  #4  
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runway1
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From: CA
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A couple good points. I'll check those.

Could a slow cranking engine be an issue? It's definitely cranking slow and unsteady.
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