HEI problems!!!!

[MJN]

The control module in my HEI keeps going out. I don't know if it is burning up inside or just something vibrating apart. Went through three of them, bought new dist. a couple months ago and had to put one in before I could drive to school. It will run the night before and the next morning it won't fire off. I'm not happy! It never started to act up until my dad hit a deer with the truck and it hasn't been the same since. Could something have been kinked or smashed? I need to know how to fix this, it isn't a cheap fix and plus it's really annoying! Thanks

[69LWB3/4Ton]

That's a tough one,, I think I would look at the altenator, are you having any power surges? When you put it in how did it get wired?

[bobs409]

I would test the power wire going to the coil to see what voltage it has. It should be about 13.8 volts. If alot higher, your truck may be over charging. If it's alot lower, the original resistor wire may still be in place and should be removed. That was only needed with the point type system.

I would also test the charging system itself if there is any doubt. Maybe the hit did something to the regulator???

[Huck]

Did your dad hit the deer with the left front? Best guess is that your regulator is not working correctly and overcharging. Those HEI modules are usually pretty solid if grounded correctly (dielectric greese under it) and correct voltage source from the ignition with key on ONLY. Check with meter key on/off ignition to HEI. Make sure the source wire is a heavier gauge then non-HEI. You might just upgrate to an internally regulated altinator and more then likely your problem will go away. Good luck----Huck

[MJN]

It was switched to internal regulator style alternator when we bought it, so no regulator. We thought it was the old dist. but the new one is doing it too. We'll look at the wiring but when we hooked it up there weren't any extra wires or odd ones. Have to check inut to coil too. Have to carry a spare module with me incase now. The only problem with power stuff is when at idle and cold the lights dim a little but when it's warm it's ok. Thanks guys.

[71GMC_3/4T]

Make sure your engine is grounded to the chassis, and that the battery is grounded to the chassis. I've seen batteries get cooked because someone thought the wire to the chassis wasn't needed. The voltage drop across the missing ground was 3 or 4 volts, making the normal 13.8 V turn into 17 to 18 V.

Get a good ignition module. If you're buying them for less than 35 or 40 bucks, you're getting cheap chinese junk ones. They won't last. Napa is a good source for good ones. Also Chevy garage.

[72 custom C-20]

Originally posted by bobs409
I would test the power wire going to the coil to see what voltage it has. It should be about 13.8 volts. If alot higher, your truck may be over charging. If it's alot lower, the original resistor wire may still be in place and should be removed. That was only needed with the point type system.

bobs409,
So lets talk about this resistor wire. It goes to the positive side of the coil to the voltage regulator. Right? Or dose it go to the bat? Prob not, needs to be regulated... (just me thinking there.)

Ok, What guage should it be? Was just back there this weekend. Replaced some parts, realy woke up the truck. The P.O. had it swaped to the HEI dist. But, as I'm finding out, It dosen't look like he was to handy. If you know what I mean.there was alot of electrical tape back there. So I'll take the dollar bet that it hasn't been changed.

thanks
David
P.s. You should of seen the spark plugs

[bobs409]

David,

The original resistor wire will come out of the engine harness and be wrapped in cloth. (white with red) This is a special type wire that reduced voltage so the points wouldn't burn up.

When HEI is installed, do not use this wire as it needs full voltage instead. The best thing to do is to just wrap the reisistor wire up with the harness incase you ever want to go back to points. Run a heavy gauge wire from the unfused ignition terminal on the fuse block to the HEI coil.

I just found this error on my truck (bought this way) and after correcting it, it's like a whole different truck! I used to have to crank....crank....crank to get it going. Now, just hit the key and VRROOOOOOM!