Topic: Tach wire grounding out distributor?

[Corellian Corvette]

Has anyone had a problem before where the tach wire is grounding out the distributor? After weeks of chasing down my no-start problem, it came to this. I've never seen this before - any tips?

[joe d]

which car, which engine and year

[Solar Gold 79 WS6]

Im having this same issue in my 79 with a 400. I hooked it up and it worked for a short while and then I had a no start yesterday. I un plugged it and let it sit 10 min and it started. This is the 2nd time it happened. The first time it happened I left it unhooked since 07 and then hooked it up a month ago just to see what would happen.  Where does the cluster ground to or what else could cause this issue??

[joe d]

if i recall, letting it sit then it starts is an over heated pcm was very common in hei dist

[Solar Gold 79 WS6]

I forgot to mention after it happened the first time I bought a new coil because I thought that was the problem.

[joe d]

pcm power control module

[Solar Gold 79 WS6]

Where is that??    or is that the ICM under the cap?  And would hooking up the tach overheat this pcm? But If the tach is not hooked up it will start no problem all the time?

[joe d]

oh i did not realize that, it is mounted to the dist under the rotor kind of C shaped i doubt the tach would over heat it

[eroc022]

if i recall, letting it sit then it starts is an over heated pcm was very common in hei dist

ignition control module.... not pcm thats a computer

[joe d]

if i recall, letting it sit then it starts is an over heated pcm was very common in hei dist

ignition control module.... not pcm thats a computer

yup i stand corrected

[Solar Gold 79 WS6]

But that wouldn't ground out the dizzy would it? I have my orig cluster Im going to throw in and see if that makes a difference. Its random. Sometimes it starts and other times it doesnt. And when it does run it just shuts off randomly when the tach is hooked up. But it will run all day long with it not hooked up!

[joe d]

kind of odd, ask EROC

[Tin Indians Rule]

Change the distributor cap and coil out. Just switch one off another HEI and test it if you have access to one. I think you will find your problem.

[Solar Gold 79 WS6]

All I have are chevy HEI's. Can I use that??

[Tin Indians Rule]

Im pretty sure an HEi cap from a GM to a GM is interchangable. Compare the two side by side. Just make sure the depth is the same. Somebody else (A Chebby Head) will confirm I'm sure. What say ye Joe, Evan, Reno???