Mopar Ignition Problems Strike Again

[Eggo]

I've grown up working on old cars but electrics has always been something I've struggled a bit with - my '73 Satellite really takes this to heart and tries to give me loads of problems to work on to get better at it .

I had an issue last year where it would run at 15-16V when I was accelerating and about 12V at standstill. When I was using electrics like turned on my electric fan, it would drop to about 10-11V. It was like this for maybe 12-18 months, had no idea why but everything seemed to work fine. Then a couple months ago I was driving home and the volts kept dropping until it cut out. I swapped out the voltage regulator for a new one and also the battery for a new one and it seemed absolutely fine, the volts would sit between 12 and 14 regardless of me driving or stopped, and turning on the electric fan wouldn't drop it.

This week it's been doing the same where it's got about 14-15V when I'm accelerating, and when I am if I have the headlights on, the dash lights shine really bright. When I stop it sits at about 12V and the lights get dimmer. Surely this isn't the regulator again as I changed it at the end of August? Seems like if it is the regulator maybe its a symptom of the issue and not the issue itself? Just a bit confused and before I order loads of parts please could I have some advice on what might be causing this. Do I need a new ballast and coil potentially? Or is it maybe the alternator? I ordered a new alternator almost exactly 1 year ago because thought that was causing the weird 15V charging thing when it was doing it last year but it was from rock auto and I've had problems with a couple other parts I've bought off them recently.

 

[Geoff 2]

Not a coil or bal res problem.

The common denominator seems to be the fan were there for both failures. Seems you get a large voltage drop when the fan are on. That indicates a large current draw. Fan motor could be faulty &/or generating a large voltage spike when switching on/off...& that spike is damaging the volt reg. A large smoothing capacitor may help.....or better still fit a factory clutch fan & shroud.

 

[Eggo]

Not a coil or bal res problem.

The common denominator seems to be the fan were there for both failures. Seems you get a large voltage drop when the fan are on. That indicates a large current draw. Fan motor could be faulty &/or generating a large voltage spike when switching on/off...& that spike is damaging the volt reg. A large smoothing capacitor may help.....or better still fit a factory clutch fan & shroud.

Yeah that makes sense, will look into a capacitor and how to fit one thank you

 

[Eggo]

Not a coil or bal res problem.

The common denominator seems to be the fan were there for both failures. Seems you get a large voltage drop when the fan are on. That indicates a large current draw. Fan motor could be faulty &/or generating a large voltage spike when switching on/off...& that spike is damaging the volt reg. A large smoothing capacitor may help.....or better still fit a factory clutch fan & shroud.

Is there a way I can test the fan motor to see if it's faulty or would a good shout be to try and replace the motor regardless in case it's that?

 

[493 Mike]

Is there a way I can test the fan motor to see if it's faulty or would a good shout be to try and replace the motor regardless in case it's that?

You would need the manufacturers specs for current draw and resistance to test. Plus a good meter.
Mike

 

[toolmanmike]

I've grown up working on old cars but electrics has always been something I've struggled a bit with - my '73 Satellite really takes this to heart and tries to give me loads of problems to work on to get better at it .

I had an issue last year where it would run at 15-16V when I was accelerating and about 12V at standstill. When I was using electrics like turned on my electric fan, it would drop to about 10-11V. It was like this for maybe 12-18 months, had no idea why but everything seemed to work fine. Then a couple months ago I was driving home and the volts kept dropping until it cut out. I swapped out the voltage regulator for a new one and also the battery for a new one and it seemed absolutely fine, the volts would sit between 12 and 14 regardless of me driving or stopped, and turning on the electric fan wouldn't drop it.

This week it's been doing the same where it's got about 14-15V when I'm accelerating, and when I am if I have the headlights on, the dash lights shine really bright. When I stop it sits at about 12V and the lights get dimmer. Surely this isn't the regulator again as I changed it at the end of August? Seems like if it is the regulator maybe its a symptom of the issue and not the issue itself? Just a bit confused and before I order loads of parts please could I have some advice on what might be causing this. Do I need a new ballast and coil potentially? Or is it maybe the alternator? I ordered a new alternator almost exactly 1 year ago because thought that was causing the weird 15V charging thing when it was doing it last year but it was from rock auto and I've had problems with a couple other parts I've bought off them recently.

Is your regulator grounded well? Have you painted the firewall and just installed the parts back on? Just asking.

 

[pnora]

Through the years I have found many poor regulator connectors. If the connector with the blue wire does not fit tight on the pin it will overcharge. Rate of overcharge will be dependent on the resistance. The regulator needs the correct reference voltage to control the charge rate.

 

[72RoadrunnerGTX]

Mopar ignition? The OP is describing a charging system problem. Sounds like the typical Chrysler high voltage drop between the regulator IGN1 and the battery. Several posts here lately on that subject.

 

[72RoadrunnerGTX]

..... Rate of overcharge will be dependent on the resistance. The regulator needs the correct reference voltage to control the charge rate.

as well as the combined resistance of every connection between the regulator and the battery.

 

[pnora]

as well as the combined resistance of every connection between the regulator and the battery.

I agree every little bit matters. But that blue wire is keyed 12 volts that not only feeds the ignition, electric choke, alternator and other item is the most critical. The regulator needs thatto work period. It works the best and is most accurate when it is as close to battery voltage as possible.

 

[72RoadrunnerGTX]

The point is, there are several other disconnects/connections, including the ignition switch itself, between the Ign1 circuit in the engine harness and the battery that is more often the source of voltage drops interfering with the regulator’s reference voltage and causing over-voltage at the battery.

 

[pnora]

The point is, there are several other disconnects/connections, including the ignition switch itself, between the Ign1 circuit in the engine harness and the battery that is more often the source of voltage drops interfering with the regulator’s reference voltage and causing over-voltage at the battery.

Did you not see that I said I do not disagree? Most of the time when it is not at the regulator plug there are other issues like running and starting problems. Being in a dealership since 1972 I can tell you I have replaced more regulator plugs than other repairs. Not that we did not repair other connections.

 

[72RoadrunnerGTX]

Interesting, in my time at the dealers back in the seventies, definitely delt with many more bulkhead, ’70 and later ignition switch Molex, and other connection resistance issues in that circuit over the regulator plug. Not a whole lot of current at the plug compared all the other connections between the reg and the battery.

 

[Geoff 2]

Should have mentioned this earlier in the thread. Is the alt capable of supporting the fans? Some fans will pull 40-60 amps. Alt output needs to high enough to support this increased load.

 

[Eggo]

thank you for all your advice, the regulator is grounded well i think and i’d previously got where it sits where the bolts go through the bulkhead down to bare metal to get a good ground. i think the connectors are in there firm as well because the connector doesn’t move at all when i wobble it. i need to look into the fans i think, they’re 2 flex a lite ones so will try and find out online how much current they draw and how much the alternator can cope with. the reg plug is not new though so will order another one of those in case that is the issue