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No spark

Roger63

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All I did is change the spark plugs. Now I have no spark. It's an old Prestolite electronic ignition with an accel super coil,that's how it came. Measured voltage at coil 12.5V on + 9.8 on distributor side. Primary resistance is dead on spec, secoundary resistance is a little high. No fire on coil wire. Any help would be appreciated.
 
check the engine to chassis ground to be sure its a low resistance.
 
Hey also be sure the ignition box has a good low resistance to ground on the case as well
 
check the reluctor gap in the distributor too. If that seems good maybe just try a known good coil.
 
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If all you truly did was change plugs and nothing else, and you state that the car ran fine prior to doing that, it's likely plug wires are where the problem lies. Times I have replaced plugs I have experienced it's difficult to get the rubber boot to release off the body of the plug. Or when you get the boot to release, the connection to the terminal of the plug did not release fully. You continue pulling on boot and the electrical connection did not release. It's easy to cause the wire to separate / disconnect from the internal boot connection. I suspect it's likely that you have damaged or separated a connection from the process of disconnecting your plug wires.
 
If all you truly did was change plugs and nothing else, and you state that the car ran fine prior to doing that, it's likely plug wires are where the problem lies. Times I have replaced plugs I have experienced it's difficult to get the rubber boot to release off the body of the plug. Or when you get the boot to release, the connection to the terminal of the plug did not release fully. You continue pulling on boot and the electrical connection did not release. It's easy to cause the wire to separate / disconnect from the internal boot connection. I suspect it's likely that you have damaged or separated a connection from the process of disconnecting your plug wires.
I will look at that, but I have nothing out of coil. I'm gonna try a different coil today.
Thanks
 
When cranking does voltage on negative side of coil fluctuate? If so, everything to coil is working as it should.
 
As posted, if all you did was change the plug wires and it ran fine before, sure would seem that a setting or connection was lost related to that install. Coil connection, disturbed or broken wire while installing, cap, reluctor, bad plug wire..
 
As posted, if all you did was change the plug wires and it ran fine before, sure would seem that a setting or connection was lost related to that install. Coil connection, disturbed or broken wire while installing, cap, reluctor, bad plug wire..
Here's the jist. When I bought the car it would start and idle fine but would fall on its face when throttle applied. So I pulled the plugs to inspect. They were carboned up so running rich right? I pulled the carb and put a kit in it and changed the plugs. That's literally all I did.
 
Define prestolight electronic ignition. There are two CDI and a add on kit.
 
My buddy had the same thing happen after he changed his alternator. He went to start the car, and it would not fire. We checked things, and there was no spark at coil or plug wires. I pulled the distributor cap to check condition of rotor and cap terminals. While the cap was off, my friend sprayed some
electrical cleaner around reluctor and pick-up coil. We put it all back together, and it started right up. MSD distributor and box. Two unrelated, but coincidental events. He has purchased a new MSD pick-up coil, just in case this event was a warning of impending pick-up failure.
 
Changed plugs, d-cap. wires and rotor on a 78 Olds no start. Checked to if everything was hooked up,all good. GM guy next, went got him he looked at it,said HEI module. Says I've got one, put it in car starts up. You never know.
 
Define prestolight electronic ignition. There are two CDI and a add on kit.

20220918_113247.jpg
that's all I got
 
That leads me to believe the trigger mechanism in the distributor and module are working. As another test, put a grounded spark plug in the coil wire, with key on, with jumper wire rub coil negative side to ground. Each time you make and break the ground the spark plug should fire if coil is good.
 
The only Prestolite "electronic" ignition system I recall Mopar using was the unit that was optional with the middle 60's Hemi and MaxWedge applications. The one I remember wss a large unit that was mostly a finned heat sink with the switching transistor on it.....but it was triggered by the points distributor. I've seen the module shown on a few industrial applications (fork trucks running propane) and some early, mid to late 60's AMC ...... AMX & SCrambler......but that's a long time ago.......Just talking out loud........
BOB RENTON
 
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That leads me to believe the trigger mechanism in the distributor and module are working. As another test, put a grounded spark plug in the coil wire, with key on, with jumper wire rub coil negative side to ground. Each time you make and break the ground the spark plug should fire if coil is good.
Yeah I tried that already no spark, but thanks. I think I'm just gonna take it all off and put a new distributor and all on.
 
The only Prestolite "electronic" ignition system I recall Mopar using was the unit that was optional with the middle 60's Hemi and MaxWedge applications. The one I remember wss a large unit that was mostly a finned heat sink with the switching transistor on it.....but it was triggered by the points distributor. I've seen the module shown on a few industrial applications (fork trucks running propane) and some early, mid to late 60's AMC ...... AMX & SCrambler......but that's a long time ago.......Just talking out loud........
BOB RENTON
I wouldn't be surprised if it did come of an industrial engine, after all it does have 2 different heads on it.
 
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