Volt Gauge Sky High

[GLHS592]

I took the Shelby Charger out the other day after I got the dash back in the car and noticed that the volt gauge was reading very high. I double checked the plugs on the back of the cluster and they are plugged in correctly. Of course, they only plug in one way. The car has a SDS stand alone fuel injection system with a carb'ed L-body voltage regulator. All the wiring looks good. Would this be a sign of a bad voltage regulator?

[GLHSKEN]

Kevin,

My 82 charger 2.2 would ped sky high (external reg) looked like I had halogen headlights (back in 1984.. hell I don't think they were even out!!!) Took it in to be tested. Tested fine.. ran it again, same thing... It was intermittent. Brought it back to be tested.. Tested fine, I said "shake it" well, it went balistic. A new reg solved it.

[8valves]

I took the Shelby Charger out the other day after I got the dash back in the car and noticed that the volt gauge was reading very high. I double checked the plugs on the back of the cluster and they are plugged in correctly. Of course, they only plug in one way. The car has a SDS stand alone fuel injection system with a carb'ed L-body voltage regulator. All the wiring looks good. Would this be a sign of a bad voltage regulator?

Take a multi meter and test the check the posts of the battery while the vehicle is idling. With the car off it should be around 12.5v (make sure it is checked after the car has been running since it's in storage, but give it a minute for any "ghost voltage" to wear off) With the car running depending on the condition of the charging system your posts should read 13.5 to 14.5 volts I believe. For your gauge to be pegged or sky high it would probably have to be out of that range by quite a bit.

Wouldn't you more lean to the idea that it was something that happened with the dash going in/out a sin a gauge hookup, even though you checked them once, since it was fine before hand. Is it a different gauge cluster and the gauge is whacked? Just throwing out some options. I'm a litle rusty on my electrical skills, it's been a while since I've had to deal with them.

Aaron Miller

BTW- the check showed up a day or so ago Kevin, thanks!

[GLHS592]

I would have tried the multi meter, but it's in my tool box across town. I'm using the same gauge cluster. I'm not sure if the voltage was doing this before the dash swap because I've not driven the car much since SDAC-15. I last had the car out before Halloween. I don't remember the volt gauge being pegged. The voltage regulator is only about a year old.

Another thing I noticed is the problem with my dim driver's side headlight and non working parking light went away. Could this be related?

[8valves]

Maybe. If those two items use the same feed wire and has some sort of resistance not allowing normal voltage to A) light the headlight properly and (B) get the parking light to come on...

And now that you have monster voltage being supplied it can push through this resistance and give it enough juice...

Just a random idea though.

That would make everything make sense, and would point back to you having a bad regulator. Or so it would seem... Your car is well done enough that I don't see it being a random old wire issue or something along those lines.

Aaron Miller

[WVRampage]

sound like a bad regulator.

[jckrieger]

Make sure all your grounds are good, especially from the regulator to the battery. My old 79 Ramcharger (same regulator) was overcharging due to some rust between the regulator and the firewall.

[GLHS592]

I'm assuming Autozone can check a voltage regulator. I will check all the wiring while I'm at it.

[GLHS592]

I started the car up tonight. This is odd. The voltage gauge was normal. Here's the catch. When the gauge is normal, the driver's side headlight is dim and the driver's side parking light doesn't come on. When the gauge is sky high, the lights are normal. What in the world?

[GLHS592]

Does this sound like a ground problem or a voltage reg. problem?

[GLHS592]

Anybody? Help! Please! I suck at electrical.

[GLHS592]

I fooled around with the car today. I fixed the headlight and parking light problem. The headlight was a bad ground and the parking light was a loose filament in the light bulb.

The voltage regulator shows normal when the engine is at idle. Any rpm over idle causes the voltage gauge to go sky high again. I'm going to have the voltage regulator checked out at Auto Zone.

[JDAWG]

sound like voltage reg, or poss bad fusible like or wiring, got a spare power module or logic module to swap?

[GLHS592]

I don't have a logic module or power module anymore. I have a standalone ECM with an external voltage regulator. The wiring looks good.

[GLHS592]

I swapped in a brand new voltage regulator. It is doing the same thing. I tested the volts at the battery. At idle, it is showing around 12 volts. When you rev the motor, it shows anywhere between 12 volts and 19 volts. I'm guessing it's a bad alternator. HELP!!

[Tony Hanna]

I can't see how the alternator could be your problem. If I remember correctly (and it's been awhile) the voltage regulator controls the alternators output by varying the power supplied to the alternator's field windings. Taking that into account, your symptoms point more toward a regulator/wiring problem resulting in too much power to the fields which would cause the alternator to overcharge. A quick way to test this would be to unhook the field wire. With the car running, it shouldn't charge at all. Maybe I'm wrong, but that's all I can come up with.

[GLHS592]

The wiring was brand new last year and I've swapped in a new voltage regulator. I just can't see it being anything other than the alternator.

Field wire? Are you talking about the wire on the alternator or voltage regulator?

[Tony Hanna]

The field wire should be running from the alternator to the regulator. If there are two of them one will run to the regulator and one will ground (I think).
I'm getting in a bit over my head here because I understand the general theory, but I don't have any practical experience with the Chrysler setup. I've been lucky enough so far not to have any problems out of the stock setup.
With that said though, in an externally regulated setup, there shouldn't be any way for the alternator to overcharge unless it's a fault of the regulator.
The only possibility I can see and it's extremely remote is that something shorted internally causing the alternator to get a full 12 volts at the field constantly.
I wish I could be more help.

[DeckSetter]

Has the high voltage fried anything else yet?

My 280ZX needed an alternator when I got it. It was charging WAY high anywhere off idle, and it fried the ignition module in the distributor. New alternator, problem solved. They told me when it charges too high the diode pattern is bad. What that means, I have no idea...

I've never had to mess with an external voltage regulator, how does that wire in? Does it wire between your alternator and battery or between the battery and accessories? If it's between the battery and accessories and the voltmeter reads straight off the battery, your alternator is probably shot and overcharging your battery while your regulator is keeping everything else happy.

[GLHS592]

Nothing has fried. I'd have to ask Kevin Davis how it's wired in because he wired it for me.