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Discussion Starter #1
Howdy. As the subject suggests, I have a 1987 Suburban. I am currently having a no spark problem. I had the ignition module and the coil tested at autozone and they were fine. The coils is getting power (12v as tested with my cheap volt ohm meter. When I pulled the ignition module out, the connector for the pickup coil disintegrated in my fingers. I pulled the distributor and replaced the pickup coil and put it all back together. No go. So, on a whim I put a new coil in, since I've heard of coils testing ok but not being powerful enough to give a spark. Still no go.

At this point the only thing I can think of is that the wiring has a fault and while it is giving 12v there is not enough current to produce a spark. The only other thing I can think of is that the ignition module isn't triggering the coil correctly. I checked resistance on the cable that goes from the module to the coil.

ANY help is appreciated.
 

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If the wiring disintegrated when you unplugged the module I would say you hi the nail on the head with the wiring being bad.
 
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Discussion Starter #3
Actually, the connector that broke apart is the wiring to the pickup coil underneath the distributor magnets. I replaced that already ;)
 

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HEI troubleshooting

If you see a lot of red dust in the distributor, it is a sign that the rotor is toast. The spark is grounding to the advance weights and causes the red dust build up. The spark grounding to the internals of the distributor keeps it from getting to the plug wires. If not, try these tests:
(Be sure to use a digital volt/ohm meter to prevent damage to ignition components) Info from: Carcraft

9. Set an ohmmeter to the low scale. Connect the leads across the HEI’s “BAT” and “TACH” terminals.
ABOVE 1 OHM: Replace coil. If vehicle still doesn’t start, go to step 11. 0-1 OHM: Go to step 10.

10. Switch the ohmmeter to the high scale. Connect one lead to the “BAT” terminal and the other lead to the coil contact in the inside-center of the cap. Switch the first lead to the “TACH” terminal and recheck.
EITHER TEST READS 6K to 30K: Coil is OK. Go to Step 11.
BOTH TESTS READ INFINITY: Replace the coil. If the engine still won’t start, go to step 11.

11. Remove the green and white leads from the HEI control module. Connect the ohmmeter from ground to either lead.
INFINITE: Go to step 12. LESS THAN INFINITY: Replace the pickup coil. If the engine still won’t start, replace the module.

12. Connect the ohmmeter across the green and white module leads.
READS 500-1,500 OHMS: Repeat Steps 11 and 12 while moving the vacuum advance with a screwdriver. If reading is still OK, replace the module.

DOES NOT READ 500-1,500 OHMS: Replace pickup coil. If the engine still doesn’t start, replace the module.
 

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Discussion Starter #5
Well it turned out to be the ignition module. The tester at autozone missed it because it was the analog/digital converter that went out. The tester feeds it a digital signal, negating the need for the a/d converter, and thus giving a false positive. The input from the pickup coils is analog, however....

This information all from a mechanic who I hired to come take a look at the truck.

Thanks all for the replies!
 
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