Ready to yank out HEI

[Phillip Johnson]

Drove the truck today to the store. It ran great. Came out 20 min later and wouldnt start.. hmmmmm.. Thought it was fuel pump until I got an eye full of gas. Had truck towed home $$$$$$. With flash light in hand and a bad attitude, I threw a timing light on it to find I had NO SPARK. I tried every wire and still no spark. Now I am really peved. I replaced the cap/coil with new and still no spark. Im ready to put my points back in and drive happy again. I never had a point problem I couldnt fix.. Anyone have any suggestions??? My truck is DEAD!

[jimfulco]

Take the module out & take it to a Chevy place to get tested. If bad, get a new Delco module, & throw another in the glovebox for a spare.

[hanssolo]

Yep. If theres 12v. to it, it has to be module or coil.

[JimKshortstep4x4]

While you are checking things, I would suggest testing the pickup coil with an ohm meter. With it unplugged from the module, it should read 750-800 ohms. The pickup coil can prevent the engine from running, also.

Good luck!

JIm

[cdowns]

well when you did the change i hope you eliminated the yellow resistor wire so you were getting 12v to the distributor

[racedvl]

I had a wire break off the pick-up coil on my cheap summit HEI that I had, replaced that and all was well again.

[tom hand]

Well your seeing what I have always known, HEI ignitions are not the "sliced bread" that everyone on this board makes them out to be. When you buy a new module get 2, you need one in the glovebox to save you on your next tow bill. The points ignition has advantages over HEI if you want to go back.

1. COST: add up all the parts to make an HEI work and you are looking a chunk of change. Add to this most "parts store" parts are not worth a crap, so you need to get your parts from a dealer or high performance catalog.

2. PERFORMANCE: Oh I can't wait to hear the backlash on this one. With stock junkyard pieces a points ignition will kick an HEI's a$$ on the dyno. First the advance curve on HEI's was designed with mpg in mind not performance. Second with stock pieces an HEI run's out of steam at 4500 rpm, while a points ignition will turn 5500 or better. I had a mild 468 dynoed at Dynotech In Memphis and the HEI would lay down at 4500 rpm, popped in a stock 1967 points distributor and picked up 15 hp. Now it is easy enough to make a stock HEI outperform a points ignition, just refer to number 1 above. Name any ledgndary high performance/high horsepower motor that GM made, all of them had points.

3. SIMPLICITY: If you can't make a points system work you need to limit your underhood activities to checking the oil. And if you will step up to the plate and spend $25 on a good set of points it will be a long time before you have to touch it again.

Let the bashing begin.

[Project1970]

Originally posted by tom hand
Name any ledgndary high performance/high horsepower motor that GM made, all of them had points.

Which is likely due to the fact that HEI wasn't even an option until 1974, and standard in 1975. Nobody goes on and on about the strength of a stock '79 350.

[Longhorn Man]

While tom is right on many of the things on his list, I will agree with Project1970 on the fact that nothing was built worth mentioning in the 70's at all, and by the time the big 3 figured out how to make power with clean emissions and decent MPG, they whole dist was on it's way into the crapper for more acurate coil packs.
HEI is not perfect, while I have spun a stock one up to 7000 rpm in my truck and never heard a single misfire, I know it would never hold that RPM for any amount of time. (asuming the engine woulda held up for more than a couple seconds)
A good quality HEI set up (stock, no cheap parts inside) will last 100,000 miles with nothing more than a cap and rotor chainge every once in a while.

[tom hand]

Originally posted by Project1970


Which is likely due to the fact that HEI wasn't even an option until 1974, and standard in 1975. Nobody goes on and on about the strength of a stock '79 350.

Yea, yea I know that, I was just making a point. I totally disagree with the HEI"s are great/points suck attitude. Points are great for people on a budget. And they are also great for people who have limited tools/troubleshooting skills. You can make a points ignition run correctly with nothing more than a screwdriver and an allen wrench. Sometimes simple is better.

[Longhorn Man]

I kinda think the same about drums up front with high quality shoes, so who am I to argue?

[1967K10]

Phillip,

Just wanted to check and see if you have the problem figured out.

[Phillip Johnson]

First thing Monday morning, Im headed to the dealer to buy the GM module. I had a "known good" cap and coil that I installed last night and still no running truck. The Module makes sense. Now, if I can bend the housing back after I hite it with the 4 pound sledge hammer (FORD TOOL) LOL... Im crossing my fingers.. Thanks for the help guys!!!!

[Phillip Johnson]

Bad news.. Module checked out ok at 2 auto parts stores.. Hmmm, back to the drawing board

[Longhorn Man]

Plenty of times the module will heat up and then crap out...but it would have fired up when you swapped in your old parts and tried it.
Have you ensured that you are getting the needed full 12 volts at the feed wire to the dist? (you did run a new wire and not the old cloth covered resister wire right?)

[Phillip Johnson]

Thanks again for all the help guys..
I went to church today, came home, took a 2 hour snooze, got up, went out and put it all back together and it fired on the first crank.. Im totally confused but heck, it runs! I smelled plastic getting hot and this little fiasco cost me the end of my fairly new timing light but IT RUNS and it lights up the tires like it never has done in the 3 months Ive owned it.. Go figure. I think it heard me think about using a 4 pound sledge on it last night (Ford Tool).. Oh well, Im happier than a pig in poop! Im headed to Calif on Thursday to pick up more parts. Thanks again to everyone. I would just like to know what I did to fix it???????
The only other question is, do I trust it for 500 miles????

[73stepside]

carry another module with ya. maybe the pick up coil is screwy. did you have condensation in the cap?



points ignition isn't bad, but it is a pain to set dwell without the windowed cap. give me a davis unified ignitions hei over any stock hei or points. the street version will turn 6500 rpm and you can run a .050 plug gap (try that with a points ignition)

[Phillip Johnson]

Everything in the cap was drier than a popcorn fart. I did put the special grease on the plate under the module. I figure that may have been the problem. Looking in the Summet Catalouge, there is a NEW GM HEI for $149.00. I still like the idea of no points but I am a bit gunshy of taking the truck any distance until I can figure out what went wrong. Once again, thanks to all for the help. This is a Great website! Great people too!

[71GMC_3/4T]

Phil,
I recently went through similar problems as you.
Truck wouldn't start. Crank-crank-crank... Pulled one wire to check it and it fired right up. Limped home with it not running right. Thought Tach was bad and disconnected it. Ran better.

Problem came back. Shotgunned the Ign Module. Ran better, but wouldn't start the next day. Jumped Batt to battery. Started. Finally eliminated yellow wire (resistance wire) like I should have 3 years ago. Ran a bunch better. Then died while running. Restarted only after cooling.

Changed out coil, thinking it was the heat problem. Ran about 10 minutes and died. Pulled it apart and reinstalled old Ign Module. Fired right up and been running ever since (except when I turn it off, of course!). Took "New" Ign module back to auto parts store. Tested fine. Five times!? They exchanged for another module anyway. Not sure I'll trust that one ever... Put it in the glove box, just in case.

Anyway, just because they're new parts don't mean they're *good* parts!

If you haven't run a wire from "BATT" on the distributor to "IGN UNFUSED" on the fuse block, make sure you do that first. You will save yourself a lot of headaches in the future!

[Longhorn Man]

The yellow wire is not the resistance one...the cloth covered one is. The yellow one runs to the starter and applys full 12 volts while cranking to make starting easier. (this is as stock per schematics)

drier than a popcorn fart

And here I thought I was the only one who ever said that.

[Phillip Johnson]

Well guys. I drove the truck 100 miles today and it runs like a raped ape! Now if I could get more than 10mpg out of it... Im still a happy pappy. My truck is runn'n great. thanks again. I just wish I knew what I did to fix it...Hmmmmmmmmmm

[ddsmith]

Philip,
You said

I did put the special grease on the plate under the module.

My question is were you missing this grease initially? I believe the purpose of this grease is to insulate the module from the heat of the distributor due to engine heat conduction. This could have caused the problem. Electronics don't like heat very much. They tend to act up when they get uncomfortable.

[Stroker]

I had a problem with a brand new HEI that was much like you described and also intemittent exept I never noticed a burnt smell. Turned out to be the pickup coil shorting to the dissy housing. Here is a link to a HEI trouble shooting guide that might come in handy if you have problems in the future. Hopefully you won't have any need for it....Stroker
http://www.chevelles.com/techref/tecref5.html

[Project1970]

Originally posted by Phillip Johnson
Well guys. I drove the truck 100 miles today and it runs like a raped ape! Now if I could get more than 10mpg out of it... Im still a happy pappy. My truck is runn'n great. thanks again. I just wish I knew what I did to fix it...Hmmmmmmmmmm

Time for OD.

[sgtjed]

i had the same problem and replaced everything exept the pickup coil. it ran great fpr a couple of weeks and died again. finally changed the pickup coil and it has run great for4 years.

i will rebuild a used hei from now on just to be safe.