My car will not turn off. I installed a new ignition switch which did the job for about 2 months, then the problem came back. the car will idle with the ignition switch off(can't really give it any gas or it will backfire) which I think means it's just getting just enough ignition to run. It's a 68 chevelle with a 454 & GM HEI. and yes I am sure it is not dieseling.

You've got a funky feedback loop going on in your harness somewhere. This happens to MSD's all the time. Their solution is to put a diode in line ( like a one way gate ). That'll solve the problem but the question remains, "why?". Since the HEI is a "one wire system" it shouldn't be hard to track down.

A quick "try it". Swap in a known working voltage regulator.
Harley

I second Harley's suggestion...I had the EXACT same problem with my ignition after I installed an MSD 6AL box. It turned out to be a faulty external voltage regulator. Put a new one in and the problem has never returned.

As a side note, I also tried the diode suggestion per MSD's instructions for 'run-on' conditions and it did not cure the problem because the voltage regulator WAS the problem in my case. Good luck - hope this helps you!

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70' Malibu - 383 'Dental Gas' Inhaling Stroker! Gold Member #39
Chevellz Alwayz!

Are you still using the "R" wire from the starter to the coil. You shouldn't be using that wire anyways, and perhaps you have a bad starter solenoid as well.
Otherwise, check your power feed where you hooked up the HEI, check for power loop/short.

Frank

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I agree with 73Malibu. Check your connections on your starter solenoid and make sure nothing is touching or a spark is jumping.

The voltage regulator is frequently the culprit as noted above. You can check this easily by simply unplugging your regulator and see if the problem stops. (and the engine)

Also, although this may have no effect on your problem whatsoever, check your ground straps.

Happened to me too. Had to replace a new "contact" style regulator with the electronic one ($9 @ Autozone) to remedy the problem. Thanks to J.Wagner for helping me diagnose the problem. As others have suggested, unplug the regulator to confirm the solution.

If you did an GM HEI conversion by replacing the "resistor wire", why wouldn't you continue to use the solenoid to coil feed? If you eliminate that wire, would there be voltage to the coil during cranking?

The stock HEI cars have no "r" post on the starter and one power wire from the ign switch to the coil. I kept The "R" wire on my car after my HEI swap and it melted 2 weeks later (Flames). Not sure why, but it was not needed anyways so I yanked it out. There will be full bat voltage at the HEI coil if it is wired properly with the one wire

Frank

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gpeklak,

These guys are pretty good , eh?
Sounds like they gave you your marching orders!

Good luck with the fix. I learned something too.

Thank you all for the advice. Unpluging the regulator did stop the engine. One question why??? I thought the regulator only reguated the current not directed or controled it. Could this be a symptom of another problem?

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I suspect that a bad regulator can send a small amount of power through the idiot light for the charge system. With the small current requirement to activate the relay, the relay will stay turned on. Another thing to try is to turn on a lot of electrical load when it is in the run-on condition , like the headlamps. This may drain off enough to open the relay.

I always had an MSD and did not have to install the diode, BUT when I replaced the ignition switch, the original was worn out I had to install the diode because the car ran on.All I did was replace the switch. Whatever!!

gpeklak,

The regulators fail. The older ones which have mechanical contacts just get old & tired and they aren't worth fixin'. They live in a harsh environment doing a dirty job. Head up to your local reputable parts store and get a new one. You'll probably notice that it weighs a lot less than the old one, that's because it's transistorised. It's $10.00 well spent. One very important point that must not be forgotten: Make sure that the Grounding from the regulator to the chasis is very clean. A dirty ground point can kill the regulator and cause other problems.

Alernatively... You could eliminate it altogether if you switch to an internally regulated alternator. See Tech Ref 14 I believe.


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The proud owner of a Canadian 64-SS with ZZ4 Power!
Team Chevelle Gold Member #37
Canadian Classic Chevelles & Beaumonts Member #350


[This message has been edited by Canuck64ss (edited 07-15-99).]

Here's another thought. I once had a similar problem with an 81 vette after I installed a new radio system. If you have installed a radio and maybe other electrical components for that matter you MUST run a new hot wire. You should not use the existing radio hot wire. It does really funky things to your elect. syst. that don't make sense normally. The guy who helped me figure it out had a 73 Camaro with the same problem that's how he knew.

The Volt Regulator problem sounds odd, I have an internal reg unit so never had that problem. I never heard about the Radio wire problem. I only run the power to my head unit though the stock yellow wire, not much draw. My amp is wired to the horn relay post. no problems.

Frank

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