HEI Problems

[DHighway]

Hello my name is Dennis and i'am new to your wonderful site, I have a 67 CST C-20 that was my fathers truck then my brothers that recently passed away, he was a mechanic and rebuilt the original 327 block has 72k and updated to HEI distributor, have never had one problem with this baby until yesterday it just quit while driving it, like someone shut the key off! in checking with a 12v tester it has constant power at batt wire to dist, but has no power at tach wire while cranking, replaced control module, nothing, could it be either the coil pick/up? or the coil itself in the cap? please any help would be greatly appreciated, it is my only way to work, and had my brother not passé last month it would be running, thank you so much.

[luvbowties]

Originally Posted by DHighway

Hello my name is Dennis and i'am new to your wonderful site, I have a 67 CST C-20 that was my fathers truck then my brothers that recently passed away, he was a mechanic and rebuilt the original 327 block has 72k and updated to HEI distributor, have never had one problem with this baby until yesterday it just quit while driving it, like someone shut the key off! in checking with a 12v tester it has constant power at batt wire to dist, but has no power at tach wire while cranking, replaced control module, nothing, could it be either the coil pick/up? or the coil itself in the cap? please any help would be greatly appreciated, it is my only way to work, and had my brother not passé last month it would be running, thank you so much.

I'd 1st check for power to dist while cranking--power only when switched "ON" is not enough checking.

Next, like you suggested, I'd suspect the pick-up coil. But do the easier 'power on while cranking' check first.
Sam

[cdowns]

me i'd check to see that you have a dedicated 12v source to the hei as plenty of guys just used the original wiring and that burns up the hei because of the resistance wiring in the original wiring

[cooperhw]

Might want to go to the Mad Electrical site. He has really good Tech tips and I believe this subject is one of them. You could even give him a call as Mark is really savvy on this subject. Here's a link;

http://www.madelectrical.com/

Tell him one of the guys from the 67-72 Chevy Trucks Forum sent you.

[DHighway]

Originally Posted by cooperhw

Might want to go to the Mad Electrical site. He has really good Tech tips and I believe this subject is one of them. You could even give him a call as Mark is really savvy on this subject. Here's a link;

http://www.madelectrical.com/

Tell him one of the guys from the 67-72 Chevy Trucks Forum sent you.

Thank you Cooperhw I went to his site and i'am ordering from his catalog, Thank you love any and all site that will bring this old girl back to better then new.

[cooperhw]

Originally Posted by DHighway

Thank you Cooperhw I went to his site and i'am ordering from his catalog, Thank you love any and all site that will bring this old girl back to better then new.

You are welcome. Mark is a great guy. Some of the literature that comes with his kits got ruined in the rain last week. I had already installed the kit so not such a big deal, but I wanted to be able to go back and reference it later on if needed. I called Mark and he sent me out new stuff on his dime. Kudos. Customer service at it's finest. I know where I will buy anytime this stuff comes up again.

[DHighway]

Originally Posted by luvbowties

I'd 1st check for power to dist while cranking--power only when switched "ON" is not enough checking.

Next, like you suggested, I'd suspect the pick-up coil. But do the easier 'power on while cranking' check first.
Sam

There is no power while cranking, and control was replaced, so I will try the pick/up coil, hopefully that's it? could it also be a bad ground? do these HEI distributors just flat out quit with no warning? cause like I said before this truck has never let me down, and I believe it was converted to HEI about 20 years ago. I really appreciate all your help and advice, cause i'am flat stumped. short of buying a whole new HEI distributor. Thanks again ~ Dennis.

[VetteVet]

Originally Posted by DHighway

There is no power while cranking, and control was replaced, so I will try the pick/up coil, hopefully that's it? could it also be a bad ground? do these HEI distributors just flat out quit with no warning? cause like I said before this truck has never let me down, and I believe it was converted to HEI about 20 years ago. I really appreciate all your help and advice, cause i'am flat stumped. short of buying a whole new HEI distributor. Thanks again ~ Dennis.

What do you mean by this?

Run a wire from the battery positive post to the BAT terminal on the distributor. Crank the engine, If there is no spark then the distributor is faulty. If it sparks then the ignition system (key switch or wiring) is the problem.

[DHighway]

What I mean is using a test light and probing the tach wire on that goes to the distributor while hooked to the positive post on the battery, it should flash everytime for each cylinder I get nothing, so im told its either the pick/up coil or the in cap coil itself.

[DHighway]

Vettevet, I was told that run from negative on the battery to batt terminal on the distributor with key on should should light and be steady, for testing the control module, and positive on battery to the tach wire on the distributor cap and cranking engine should flash test light, and that test is for the control module. Now im confused did I mix up the procedure for those tests?

[67 chevelle]

Originally Posted by VetteVet

What do you mean by this?

Run a wire from the battery positive post to the BAT terminal on the distributor. Crank the engine, If there is no spark then the distributor is faulty. If it sparks then the ignition system (key switch or wiring) is the problem.

This is what I would do , if you power the distributor and it does not fire , its a distributor problem, making sure the wire from the selinoid is hooked so that you have power while cranking , if it does fire its a wiring problem , my guess is a wiring problem , as you say there is no power to the distributor . Could be the distributor is hooked to a random fuse , Ive seen that most of the time , check your fuses , the power wire to the distributor does not flash

[DHighway]

Thank you for you advice 67Chevelle, but I fixed it, it was the pick/up coil, and the shaft was worn as were the advance cuve weights, so I bought a performance distributor, and it fired right off.

[VetteVet]

Here's some ideas.

http://www.google.com/custom?domains...D%3A1%3B&hl=en

[franken]

The tach output on the distributor is just that--an output. It means little as a test.
You need to check the 12V input to power the HEI.
If the engine cranks, you most likely don't have a ground problem.
So assuming 12V in, and no spark, best guess w/o pulling the cap is a bad module. Maybe the coil, but that's rare.
Simply ordering and shotgunning parts is a great way to waste money, and not much more. For some reason, people choose the most expensive part that's hardest to replace to swap for no reason. What did you choose?

[DHighway]

Originally Posted by franken

The tach output on the distributor is just that--an output. It means little as a test.
You need to check the 12V input to power the HEI.
If the engine cranks, you most likely don't have a ground problem.
So assuming 12V in, and no spark, best guess w/o pulling the cap is a bad module. Maybe the coil, but that's rare.
Simply ordering and shotgunning parts is a great way to waste money, and not much more. For some reason, people choose the most expensive part that's hardest to replace to swap for no reason. What did you choose?

I went and bought a coil and tried that, NO START. So I pulled the distributor and realized there was quite a bit of slop in the shaft, grabbing the cam gear and it moves side to side, plus the advance curve weights were also sloppy, so everything was pointing to the pick/up coil, instead of replacing that part I bought a ACCEL performance replacement distributor for 129.99, put the new coil in the cap cause it didn't come with one, dropped it in and it fired right off, course it was dark and I missed TDC by a tooth or two but that's an easy fix, when its light. Thank you for all your help and advice, and I look forward to picking your brains again, as I assure, I will once again be needing help. I want to upload some pics of my truck, but cant remember how to zip them.

[DHighway]

Originally Posted by franken

The tach output on the distributor is just that--an output. It means little as a test.
You need to check the 12V input to power the HEI.
If the engine cranks, you most likely don't have a ground problem.
So assuming 12V in, and no spark, best guess w/o pulling the cap is a bad module. Maybe the coil, but that's rare.
Simply ordering and shotgunning parts is a great way to waste money, and not much more. For some reason, people choose the most expensive part that's hardest to replace to swap for no reason. What did you choose?

Yes it was the pick/up coil, and instead of pull the pin and removing the cam gear I replaced the distributor, the advance curve weights were sloppy as was the shaft, so it was time to go, did its part for over 20 years, thank you for all your help, with the passing of my brother who was a mechanic, you are my only help, im treading some new water here , but love a good challenge.

[VetteVet]

TRY THESE

http://www.google.com/webhp?nord=1#n...EI+DISTRIBUTOR

[Taibo]

Originally Posted by DHighway

I went and bought a coil and tried that, NO START. So I pulled the distributor and realized there was quite a bit of slop in the shaft, grabbing the cam gear and it moves side to side, plus the advance curve weights were also sloppy, so everything was pointing to the pick/up coil, instead of replacing that part I bought a ACCEL performance replacement distributor for 129.99, put the new coil in the cap cause it didn't come with one, dropped it in and it fired right off, course it was dark and I missed TDC by a tooth or two but that's an easy fix, when its light. Thank you for all your help and advice, and I look forward to picking your brains again, as I assure, I will once again be needing help. I want to upload some pics of my truck, but cant remember how to zip them.

Good show!

[mike16]

dialetric grease is important to cooling the control module. If you skimp on it or dont put any at all on it the module will fail.

I made this very mistake. brand new module failed in less than 3 months.

[VetteVet]

Kudos to you and my sympathies for your brother.