ignition issue? ballast resistor hot.

Posted By: Shaggy

ignition issue? ballast resistor hot. - 05/17/10 07:05 PM

1978 dodge truck 4 pin ballast. Been parked 4-5 years, but was my daily driver before this. Got it running again, but it seems to be cooking the ballast resistor. It will restart fine again if left to cool off. Amp gauge is reading high so I think it might be overcharging??? Will a bad voltage regulator cause this?

Posted By: HealthServices

Re: ignition issue? ballast resistor hot. - 05/17/10 07:06 PM

Don't understand the question is the truck not starting or are you worried the resister is getting hot?

Posted By: Sinitro

Re: ignition issue? ballast resistor hot. - 05/17/10 07:10 PM

If the charging system has a problem of high output voltage, then the ballast resistor will run very hot.. Eventually it will burn itself up because its resistance increases as it heats up forcing it to absorb more voltage...

Just my $0.01..

Posted By: RapidRobert

Re: ignition issue? ballast resistor hot. - 05/17/10 07:21 PM

Might slow charge the battery on a charger overnight

Posted By: MoparforLife

Re: ignition issue? ballast resistor hot. - 05/17/10 07:24 PM

Ballast resisters run hot. You don't want to touch one at an time. New they will smoke.

Ballast resister should have nothing to do with the rate of charge.

Posted By: Shaggy

Re: ignition issue? ballast resistor hot. - 05/17/10 07:37 PM

It will start and run when it's cold/first started. But if run for awhile then shut off it won't restart and it acts like a bad ballast as it fires once after cranking over and then the key is released due to no start. Starts fine again after cooling off for a bit. It's charging at 14.78 volts. Can the voltage regulator be tested?

Posted By: Shaggy

Re: ignition issue? ballast resistor hot. - 05/17/10 07:38 PM

Quote:

Might slow charge the battery on a charger overnight

Did that.

Posted By: MoparforLife

Re: ignition issue? ballast resistor hot. - 05/17/10 07:43 PM

If it were the ballast it would not be intermittant like that. Once burnt out they are dead.
Are you sure that yo aren't boiling fuel out from the carb into the intake causing a flooding condition. Have you tried to start it holding the gas pedal to the floor to unload a flooded engine.

Coils can also have thermal breakdowns.

Posted By: RapidRobert

Re: ignition issue? ballast resistor hot. - 05/17/10 07:53 PM

When it's good & hot & acting up I'd have a helper turn the key to "start" with you under the hood checking voltages at the coil/ballast and do you have another good dist you could plug in at that point in time and spin it by hand to see if it's the pickup. yes charging the batt suggestion was not for the ballast but was for the bulkhead as to not aggravate things any further till you sort it out

Posted By: Shaggy

Re: ignition issue? ballast resistor hot. - 05/17/10 07:54 PM

Quote:

If it were the ballast it would not be intermittant like that. Once burnt out they are dead.
Are you sure that yo aren't boiling fuel out from the carb into the intake causing a flooding condition. Have you tried to start it holding the gas pedal to the floor to unload a flooded engine.
Coils can also have thermal breakdowns.

Pulled the coil wire and just get the one spark when it won't start when the key is turned off.

I think this all started after I washed off some of the grime from sitting so long last night. Not under the hood though. Was working fine before that or so it seemed.

Posted By: RapidRobert

Re: ignition issue? ballast resistor hot. - 05/17/10 07:57 PM

Quote:

pulled the coil wire and just get the one spark when it won't start and the key is turned off.

Sounds like classic ballast issue sort of but the last time my old truck acted like that it was the ECU

Posted By: MoparforLife

Re: ignition issue? ballast resistor hot. - 05/17/10 08:02 PM

Quote:

Quote:

pulled the coil wire and just get the one spark when it won't start and the key is turned off.

Sounds like classic ballast issue sort of but the last time my old truck acted like that it was the ECU

I agree Robert but cooling off wouldn't bring the ballast back to life. It could a coil, ECU, or pick up coil with thermal breakdown. But when the connection in a ballast is burnt off it is gone.

Posted By: SomeCarGuy

Re: ignition issue? ballast resistor hot. - 05/17/10 08:21 PM

Sounds like a bad ECU, or more likely a bad ground to the ECU. Rusted from sitting I bet.

Posted By: RapidRobert

Re: ignition issue? ballast resistor hot. - 05/17/10 08:25 PM

Quote:

I agree Robert but cooling off wouldn't bring the ballast back to life. It could a coil, ECU, or pick up coil with thermal breakdown. But when the connection in a ballast is burnt off it is gone.

Correct. Yeah I seem to have gotten distracted from the OP ballast Q from the getgo on this thread. One of those days

Posted By: Shaggy

Re: ignition issue? ballast resistor hot. - 05/17/10 08:31 PM

I had pulled the ecu and remounted in in case it had bad ground to fender. Swapped in a different voltage reg and now see a max of 14.02 volts at around 3000rpm. Thing is now it seems fine again. I pulled and cleaned up a few electrical connections too so.....I hope this issue don't come back!!!

Posted By: SomeCarGuy

Re: ignition issue? ballast resistor hot. - 05/17/10 08:51 PM

Sounds like it was a bad ground.

Posted By: JonC

Re: ignition issue? ballast resistor hot. - 05/18/10 01:21 AM

It sounds to me like the resistor is in the circuit when trying to start which works somewhat ok when cold but not hot.

Posted By: dave571

Re: ignition issue? ballast resistor hot. - 05/18/10 02:16 AM

Quote:

Sounds like it was a bad ground.

Bad ground or other connection problem IF it stays gone now.

If not, it's just an intermittant component you haven't found yet.

Your previous(prior to the reg change) voltage readings were fine. You asked abouth testing the regulator. By reading the voltage with it running, that is what you did.
Changeing the regulator, to the one you have now, with the slightly lower reading, should not have affected anything. Not any good components anyway.

If it stays gone, it was a resisitance in a connection somewhere getting hot. If it comes back, ikt's a resistance in a component (pickup coil, ecu) doing the same thing.

Posted By: Supercuda

Re: ignition issue? ballast resistor hot. - 05/18/10 11:16 PM

I could very well be the ballast, it's called an intermittent OPEN. If there is an open in the resstance wire the ballast is made out of it will get larger as it heats up. It is entirely possible that, cold, the break touches fine, but as it heats up and thnigs expand the connection is lost and the enigine dies. Once it cools off it works, classic intermittent open behavior.

Easy test, jumper out the ballast and see if it runs then, pull the jumper and see if it dies again.