Hot Rods Sbc ignition module help

I have a Chevy 305 with hei ignition and keek burning up ignition modules. I am using the dielectric grease but can't figure out why they keep going bad. Any help would be greatly appreciated.

 

I am using the dielectric grease

Dielectric grease is for connections.

Heat sink compound goes under the module

 

hi. I was told that if you disconnect the battery with ignition key in on position it will fry the module.
Jimie

 

Haven't disconnected the battery and the stuff I'm using under the module is what comes with the module

 

Test your coil and make sure the rest of your secondary ignition is up to par. I got too good at changing modules in my wife's old 76 Cad Seville until I changed the coil. Had the same thing happen on my Dad's Olds. He fried modules as soon as the coil got hot and had an internal issue.

 

Brand new coil

 

Bad cap, rotor or ignition wires will cause premature failure of the module.

 

get a gm module friend of mine put two or three parts store modules on. finally got a real gm no more problems.

 

^^^^^^^^ What he said

 

If you have changed the dist. cap recently make you switched the metal ground strap into the new cap. If you forget to do that it will burn up the module.

 

I have an OT truck that had all new HEI components and it kept cooking modules. It also kept blowing tail-light fuses because a previous owner had annihilated the rear wiring for trailer lights I guess. Got an unmolested wiring harness from mid-frame back at a junkyard. (Wires, grounds, light sockets etc.) Replaced the junk wires and quit blowing fuses and ignition modules. So I guess the question I ask is do you have any seemingly unrelated electrical gremlins?

 

Nothing else seems to be wrong no fuses blown yet

 

You are running a full 12 V to it correct? low voltage is as hard on electrics as high voltage.

There were two different coils that had different colored leads coming out of them. I have no idea what the difference was but someone once told me that you had to run the correct coil for your distributer.

Make sure that all your connections are good as in no corroded connections to the distributer, also make sure that the hot to the distributer is off when the key is off, voltage bleed to the distributer will fry the module.

Ok that's all from the beaner. LOL

 

Your pink ignition wire should be at least a 12ga. Also good grounds on the car. Be sure to get a good brand module like the others said.

 

Get your hands on a GM Shop Manual - they have a flow chart for the HEI that just can't be BEAT!

Check the pick-up for RESISTANCE - should be within spec. 'Been told a bad pick-up will shorten module life. Check the coil as well for resistance values, replace if need be.

IIR, you should have a 10-ga. wire to supply 12 VOLTS to the coil - the HEI draws a fair amount of current, thus the need for a stout wire to supply the coil (+).

SOME HEI modules will give some warning - I've seen them cut-out when the engine comes up to temp and not restart, cut-out and usually restart when hot, AND just outright fail the next time the vehicle is started! Might be worth carrying a test light with you to check it, for good karma. Connect the clip to ground, the probe to the coil (-) terminal. With the key ON, the light should be BRIGHT. Crank the engine - the light should cycle between BRIGHT and dim if good. If the light remains bright, it's bad.

I've replaced FIVE modules over 19 years in a '82 S-10. Not a DAMN-ONE of the aftermarkets lasted as long as the Delco OEM unit! Last one I put in was a Niehoff, with a 5-year warranty (on a Sunday), so shop around if you can't get a Delco, for the BEST warranty. GO with a DELCO if you can!!!

Hope this helps! Good Luck, Tim

 

most of the time it was low voltage like PNB said they have to have 12 v , and they do not like heat . the only good units I find to work are standard electronics , General motors ( beware lots of china counterfiet ones, GMs are Black ) or Accels . and if they were grey to stay away as those were the cheap offshore ones

 

Little carbon piece with the spring should be replaced and dielectric greased. It's what the coil pushes against inside the cap against. Rotor touches on the other end.

 

Just ordered a new accelerate module and cap and rotor

 

Ok I've changed the module to an accel module , car ran great in the driveway but out on the road skipped and just shut down 1/2 mile out the coil cramped out ( brand new coil) put old coil back in car started back up but still sputtering

 

Pick up coil issue?

 

do a wiggle test ( ohm meter and move the pick up coil back and forth to see if it drops ) on the pick up coil wires as they are fragile and break if they are old and very thin some times they are intermidnet and will kill the motor when the vacuum advance moves the unit
. as for a ignition coil going bad that is rare unless its a cheap one . the old one if its OEm should work , this will help for checking the coil

 

This is all we know about it.

No answer to this question.
"You are running a full 12 V to it correct?"

Some more information would be greatly appreciated.

What car is it going in???
What other wiring is it hooked to????
Old or new???

6 or 12 volts???

Anything else in any way connected to the distributor.

 

Sorry yes it's 12v in a 31 model a roadster , old distributor and nothing else connected to it.

 

OK, thanks.

How many pins on the module???

 

4 pins

 

You don't say what your experience with these distributors is, so if I get too detailed please don't take offense.

4 pins. This is a pretty basic type. If it is wired correctly there is no reason it should be doing what it is doing.

Coil grounding is important. ****As you face the front of the coil where the wires come out****, the coil has to be grounded by connecting the wire with the round terminal to the coil frame with a coil mounting screw. Another wire or metal strap goes from another coil mounting screw on the coil to the center terminal in the cap connector.

If your other 2 wires are red & yellow, the red is coil+ which is the right side connector of the cap plug, the yellow is coil- which will go to the left side of the cap connector. Your 3 wire cable from the distributor goes in the rear section of the cap connector. Make sure the connections for the 3 wires are clean & tight inside the distributor.

12 Volts can be connected to the front pin on the right side of the cap connector. As mentioned in POST#15, use a heavy wire.

Connect battery+ to the terminal with the red coil wire, battery ground to engine block. Clamp the distributor down with the usual hold down clamp, 'specially if you have a gasket between the distributor & the engine. The distributor must be grounded.

Crank.

If your pickup coils are any good it will run the way it should.

Some other information about them:
http://www.crankshaftcoalition.com/wiki/Hot_rodding_the_HEI_distributor

 

I see you have 2 threads going on this:
http://www.jalopyjournal.com/forum/threads/turns-over-but-no-spark-help.978194/

You said there:
I have an 86 sbc 305
Yes it is hei . I got the motor out of a running truck so I know it ran good but now no spark

If the above is true, it was operational.

All it should have taken was one wire to feed it +12 volts to the proper connection and a connection to battery minus. (ground)

Are you using the old Ford positive ground system on the rest of the car??

 

Is your engine grounded? Check for ground at the distributor housing. Check the wires on the pickup coil, do a pull test. Last thing to do is put in another distributor.

 

Lots of good info here, but don't miss this one!!

 

Not too long ago on here somebody was having HEI problems similar to yours. He finally ended up changing the condenser. Problem gone. Have you done that???