HEI conversion problem: no spark while cranking

Trailbeast,
Thanks for posting that. Interesting you mentioned you use the stock OE distributor. One concern I have is that the Ohm resistance with the pickup coil is not compatible with the GM module. GM pickup coils are 500 to 1500 ohms according to my internet research. OE was measured to be about 280 Ohms. Apparently, this isn't a problem. So, I will continue to troubleshoot, this weekend. First, monitoring coil voltage input as suggested by 67Dart273.

iScamp said:

Trailbeast,
Tell me about your conversion kits or direct me to a place on the forum/internet that I can learn about it, please. Do you still sell them? Pictures? I'm very interested. The components on my car appear to be a hodgepodge of parts.

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If taking from a junkyard GM V-8 (1985-95 trucks, to 93 in cars), also take the GM cable from the module to the coil. Also take the pickup connector and wire (snip at GM pickup). You have a 50% chance of connecting the pickup polarity correct to your Mopar e-distibutor. One polarity gives an erratic spark. You want it to spark when the pickup teeth align (flash a timing light). You can wire the white GM "tach" wire to an electronic tachometer.

iScamp said:

Trailbeast,
Thanks for posting that. Interesting you mentioned you use the stock OE distributor. One concern I have is that the Ohm resistance with the pickup coil is not compatible with the GM module. GM pickup coils are 500 to 1500 ohms according to my internet research. OE was measured to be about 280 Ohms. Apparently, this isn't a problem. So, I will continue to troubleshoot, this weekend. First, monitoring coil voltage input as suggested by 67Dart273.

Click to expand...

The signal from the pickup is a voltage signal. I don't think the 8-pin module draws significant current from it, so its resistance shouldn't matter. See Kit Carlson's many posts here for full info. He shows O-scope traces. Just assure you wire the polarity correct (use timing light). Also twist the pickup wires and route away from HV spark wires, otherwise it might get positive feedback (like a mic & amp) and self-spark rapidly. The 8-pin module needs to be bolted to aluminum (as GM did in their distributor). I used a cut piece of PC CPU heat fins & thermal grease. Also, one mounting screw must be grounded to BAT-. Don't rely on a rusty screw to the body as Mopar did.