Lost spark

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CoggedBelt75

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I'm assuming it's wired like this

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HotRodPC

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78C10BigTen said:
Sometimes even flyin down the interstate at about 80 in the passing lane they just decide bye bye im out and the vehicle dies right there.... ask how i know lol
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And sometimes you go into a 7-11 get a Big Gulp, come out and it won't start. ICM it is. This is why if you ever get a known good one, toss it in the glove box.
 
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HotRodPC said:
And sometimes you go into a 7-11 get a Big Gulp, come out and it won't start. ICM it is. This is why if you ever get a known good one, toss it in the glove box.
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I have a whole spare dist in my truck tool box. That one i took the icm out for a friend one day because he broke down. Always good to have.
 
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85 SQ said:
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I just bought new parts for the dist . Old parts on the left new on the right . My question is why does the new ICM and pickup coil only have 2 prongs where the old ones have 3 . Did I get the wrong parts . The coil looks the same except the new one came with the metal ground bar do I need to use that . Thanks for your patience . This old stuff is new to me I'm usually dealing with fuel injection coil packs and a code reader lol
 
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HotRodPC said:
OK, I say it's doubtful you have a pinched wire if you know for a fact all wires are plugged in cuz I don't think they'd reach the dizzy cap of one was pinched between the block and intake.

So the next thing I'd check and have a feeling there's a chance that it's the dizzy rod to the oil pump. I'd pop the dizzy cap off and crank the engine to make sure the rotor is turning. Maybe it's not seated all the way or some other mishap and if the rotor doesn't turn it's going to give a fake no spark. Meaning, there's spark, it's just not being distributed to the plugs.

I know all this seems stupid, but since it was running fine BEFORE you took it apart, just going over all the basics FIRST.
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Rotor turns got the dizzy meshed with cam gear and then got the extra little clunk when it seated with the oil pump drive shaft
 
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Matt69olds said:
Do you have power on the pink wire with the key on? It should be plugged into the battery terminal of the cap. With the key on, you should have power on the tach terminal. Use a test right on the tach terminal, the light should flicker when you crank the engine. If not, either your pickup coil or ignition module died. Look closely at the wires for the pickup coil. The tend to break from the constant movement of the vacuum advance. Broken wires=no spark. You can have the ignition module tested at most parts stores. If you reinstall it, make sure you apply the heat transfer paste on the bottom of the module.
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12.25 volts at the pink wire
 
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The module on the right is the typical old school HEI module, the one on the left I’m guessing is your some kind of primitive timing control. The vacuum advance can rules out the later CCC electronic spark control. I’m wondering if you could replace the pickup coil with a standard 2 pin and use the module on the right. If not, maybe the parts store can identify and find the 3 pin module.
 
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The 3 prong is for ESC Electronic Spark Control distributor. Take it back. They gave you what the book called for but someone has swapped out your dizzy for NON ESC type.
 
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HotRodPC said:
The 3 prong is for ESC Electronic Spark Control distributor. Take it back. They gave you what the book called for but someone has swapped out your dizzy for NON ESC type.
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You lost me here if the three prong is for esc wouldn't that mean I have the ESC type dist since it had the three prong on it the original pickup and ICM are both three prongs the new stuff only has two
 
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85 SQ said:
You lost me here if the three prong is for esc wouldn't that mean I have the ESC type dist since it had the three prong on it the original pickup and ICM are both three prongs the new stuff only has two
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OK yeah. My bad. I was backwards cuz it's usually the other way around IIRC. At any rate, point is, one ICM is for the ESC, one is not so you want the one that matches what you have. But that does bring me to, are you certain the 4 prong plug on the back of the dizzy is plugged in to the ESC ECM? It won't work if it's not plugged in too unless someone has done a modification to delete the ESC. You can do that by cutting 2 wires and twisting them together. If the ESC is hooked up and working, I'd keep it though. It's not a bad system if you're running a stocker.
 
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85 SQ said:
Def no spark and I'm running a clear glass filter so I can see the fuel I'm also sure the wires are plugged in correctly and like you said the bat/ign wire won't plug into the tach side . I have not checked to make sure there's no a wire pinched under the intake it's doubtful bit worth a look . I checked the resistance between the tach and battery wire connects on the coil and it was less than 1 ohm test out at like 0.1
Which should be good . I think it's the original coil though it's got 7/16/85 burned into the top and it Def looks well used . I'm picking up an accel coil tmrw and see if that gets me anywhere thanks
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Is there 12v at the single distributor power wire when the key is on?
 
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