At this point, it's an anecdote, but I still wonder about it all the time. I dropped a used HEI into my `72 LeMans. To eliminate any potential wiring issues, I ran a wire from the battery to the HEI coil, until I got it running. Obvoiously that never happened. So, here's where the weirdness starts...

With the used GM HEI module, it always started right up and idled well. But anything above 2000 rpm, there was a nasty pop through the carb. :mad:

With a new module, it almost never started, but when I managed to get it started (VERY difficult), it ran a little rough, but no backfires. :confused:

Anyway, I threw in the towel and went back to points...at least I know it will start. smile.gif

So what gives? I've heard that the generic parts store HEI modules are generally unreliable. Anything else? Perhaps the pickup coil? Faulty GM module?

Thanks in advance!
graemlins/beers.gif
-Henry

What did the HEI come out of?? Are you sure you didn't install it 180deg out? What was the timing set at when you did get it to run??

Joel,


The HEI came out of a 1977 Trans AM with a 400 4bbl. Bear in mind that I had the old GM HEI module in it when installed. No starting problems (but carb popping) until I replaced the module.
The starting problems occurred after the module was changed.

If I remember correctly, the timing when I put it in was 30BTDC. I then set it to the factory specified 12BTDC for the LeMans 350.

I don't know if it was installed 180 degrees off.
This did cross my mind, so I ended up taking out the dist and brought #1CYL to TDC. I then reinstalled. It made no difference, so I am fairly certain the dist. was correctly installed.

I would love to crack this mystery at some point becuase I would like to do away with points at some point in the future (pun intended). :D

Thanks!

-Henry

Henry, if you feel like the distributor was in correctly and the wiring was right then the only other thing I could think of(outside of the module)would be the distributor itself.Each dist. has advance built into it by the factory.Like an 80's Camaro 305 dist may have 15deg and a 350 may have 20deg- etc.Maybe you didnt have enough- or too much timing in that distributor to begin with...just a thought though-If it isn't too much trouble could you post up the ID# on the distributor just for grins. :D

The only other thing I've read on this is possibly there wasn't enough dialectic grease on the modules and they are getting too hot causing an intermittent failure...

Definitely got me curious now :confused:

Joel,


Unfortunately, this High Energy "Adventure" happened about 3 years ago. I don't have the number anywhere. :( The ebay seller insisted that the dist. was fine, but was more than happy to take it back, no questions asked.
So I guess it worked out.

There isn't much else I can think of. I never tried a new GM module, but that might have done the trick. I made sure there was enough dilectric grease on the plate, so that wasn't an issue.

The mystery continues. :D


Thanks!

-Henry

You can't leave us hanging on this now :(

So you don't have the distributor anymore???DRAG

I thought one GM HEI was as good as another but never tried switching breeds as it were, I always run SBC except for my wifes 69 LeMans and I never had the distributor out but it sounds like a timing problem?? With the poping and all back through the carb? graemlins/clonk.gif Would a vacume leak cause the same problem guys? graemlins/clonk.gif


Tazz

I never had any problems with HEI's..new module,old module,Mexican module,Chinese module ;) :D
Many years ago,I put a yellow/red wire coil on an HEI that had a white/red wire coil originally (or something like that-those that know HEI's will know what I'm talking about) and the car was hard to start,and ran crappy) Switched it back to the original coil,and it was fine.