So, about ten years ago built a friend a 36 chev pickup, 350-350 combo, I wired it, been an absolutely great truck all these years. However, he has been through at least five ignition modules in ten years, all have failed when the truck has been parked in his garage, (or the last time he parked it). In comparison, my 36 ford pickup, 327-350 combo, has never fried a module in 17 years on the road. Any of you got any ideas why this happens? Both have stock hei distributors, both trucks wired the same, both put out 14.5 volts steady, no fluctuations, good steady power. Really just trying to understand why this happens, thought some of you may know. LeRoy.
under the cap where the coil is,are 4 screws that hold it in place.One of these screws has a ground strap that goes to the 3 prong plug. Make sure that the coil screw and strap are completely clean.
Thanks, there are grounds everywhere, something I learned early when I started wiring cars, maybe, though, the ground on the engine may not be as good as it could be. I'll get him to check.
The ground being referred to is inside the distributor. Also, I've learned to carry spares for all the internal parts to my HEI, including the coil which can - and does! - fail unexpectedly. Good luck!
Make sure to use the heat sink grease. That white stuff under the module is there for a reason other than getting all over your hands.
Here is a picture of the often missing ground strap. End of the strap goes into the middle hole on the HEI wire plug. I stole the picture off the internet (from a Jeep forum, no less) but it is the best one I could find.
CHECK the pick-up for resistance with an ohm meter - it should be in the 500-1500 ohm range. A pick-up outside of that range WILL shorten module life. USE an AC-DELCO module! I have installed FIVE modules in a V-6 S-10, in 19 years and 215,000 miles. NONE of the aftermarkets lasted as long as the factory module... it went 60k! Good Luck, let us know what you found out. I really like the HEI, easy to trouble shoot with a test light and a multimeter. Tim
He says it all looks good, he's used aftermarket modules in the past, found an old hei distributor and used the ac delco module out of it, says it's all good now, we'll see, time will tell. Thank you much guys, LeRoy.
Some interesting comments. Delco no longer make any products and reboxes or sources all parts today. The new modules are no where near the old modules with all the protection circuits in them. His car is more that likely fixed if he found a old style module,,,,,,
If what Delco sells these days is junk then go harvest at the local yard.. GM made plenty of HEIs for everything and I think the modules and coils are very interchangeable. I think I have 3-4 coils and modules that I have kept for this reason. Working at a parts store helped re-enforce that the new stuff is trash.
I have a v8 s-10 pickup with HEI. A previous owner had butchered the wiring to rear lights. It got to the point where it would blow the tail-light fuse about once a week and...for some reason...it would cook the ignition module about once every two months. Found a good unmolested wiring harness from the mid-frame plug all the way to the light sockets to replace it all with. Fixed both problems.
Ha! Had this happen to me today. The spade connectors in the distributor had lost their tension. Third module in a short period of time. I tightened up the connectors by squeezing them slightly, then put a module back in that I thought had failed (engine died, no spark) and it fired right up and idled for 20 minutes. Lots of heat cycles, even these hei distributors are getting old. Posted using the Full Custom H.A.M.B. App!
Agree on needing three things mentioned: 1. Good ground 2. Electrical wires with solid connections 3. Heat sink grease under the module.