OK, I know I am often not the brightest light in the evening sky, but I am having trouble getting an HEI distributor to fire!!! This is a V-6, '79 Buick Turbo, HEI dist. how often does the capacitor go bad on these units? I have replaced the module, no luck. next is the pick-up. Any other ideas or suggestions. dan dlmarx@bellsouth.net
Make sure you have a full 12 volts going to it. If you're feeding it with the same wire that fed your points distributor, chances are it's a resistor wire and is only 6.5 volts.
Ok, I have no spark at the coil. I have a direct line from the battery to the battery terminal on the HEI. Have power at the new module, still no spark at the plug.. How do I test with a battery charger? Thanks. Dan
alligator clips, spin it by hand, if it sparks an open spark plug on the bench, its a ground issue. is the coils grounded? there is a little strap that goes under the cover. if you hold power and ground to the coil, then pull ground off, it should collapse and spark. I always pick up coils, and modules, whenever i am at the junk yard. use the dielectric grease too.
Pick up coils were a notorious failure in HEI's. To test, hook up a ohmmeter and move the leads of the coil around in any and all directions. The needle should not move at all, should show no resistance. This indicates continuity in the coil windings and the green and white wires to the connector. From there, check the terminal block for a broken lead. You are sure that the coil is good, right? And like a earlier poster indicated, be sure to use the dielectric grease between the module and the distributor housing. The modules cannot tolerate heat being transmitted from the distributor housing. A sign of that occuring is that the engie will run for awhile until the module heats up. Car will quit until the module cools down, then restart. I doubt that it is an issue with the coil contact to the distributor rotor. With the voltages produced by those coils, it was amazing to me on how much of a gap it would fire across. I once saw a 305 Chevy that the center of the distributor cap was completely burned away, the contact between the coil and the distributor rotor was destroyed and laying in the bottom of the distributor, and it still ran, not real well, but it still ran. I knew of techs that back in the old days would spray modules with R-12 to cool them down enough to restart. 'Course one of them used to cool his beer at work the same way.....not environmentally friendly I hear tell.
Had one give me trouble for about 4 hours in 0 degree weather. Checked everything and it was ok, took the rotor off took it inside and held it up to the light, looked good, put back on no fire, took the rotor off again and held it up against the sun and there was a pin hole right through it. New rotor and it fired right up. Electricity will follow the easiest path to ground especially with a large gap in your sparkplugs.
If yours is a 79 turbo, does it have the 5 pin module? If so, there's more to the circuit that matters. I had a similiar problem (no spark) and it was the knock sensor spark retard system.
This goes into testing coil (in the cap) and pickup coil http://www.performancedistributors.com/technical.htm Pretty sure that the '5th' pin is a timing retard feature (knock sensor) It would run with it unhooked but timing would be "locked" and slow. But should at least 'spark'.
If you have it, plug it in. If you don't, grounding the pin should retard the timing 10 degrees and make it fire. What I'm not sure about on these early modules with the retard is what signal is on the pin when in normal operating mode. Straight 12 Volts? Sine wave? Square wave? Another way to test the rest if the distributor would be to temporarily substitute a 4 pin module and then check for fire.
The Jalopy Journal
