voltage gauge pegs

greg schroeder · #1 (**permalink**) 12-07-2006, 05:23 PM

Has anyone experienced the voltage gauge pegging on 50 amps? It seems as if the regulator?, is trying to have the alternator charge a severely discharged battery even though the battery is fine. The condition is intermittent, fine one moment, then sudden load on the alternator and the belt squeals away.

Any points to first check would be appreciated.

xlr8or · #2 (**permalink**) 12-07-2006, 06:01 PM

That would be the Ammeter not a voltage guage. I would pull the alternator and have it tested.

Rick Parker · #3 (**permalink**) 12-07-2006, 06:23 PM

Check the regulator(remote mounted), one of the sets of points in it are probably burned and sticking, causing it to violently overcharge. I had the same thing happen at the WSCB in May and had to hike a couple of miles on foot from the hotel to get a replacement regulator at the NAPA store. If it is an internally regulated alternator, it needs to be replaced (if the regulator part cannot be serviced separately) before some wiring gets cooked.

greg schroeder · #4 (**permalink**) 12-08-2006, 10:52 AM

Quote:

Originally Posted by Rick Parker

Check the regulator(remote mounted), one of the sets of points in it are probably burned and sticking, causing it to violently overcharge. I had the same thing happen at the WSCB in May and had to hike a couple of miles on foot from the hotel to get a replacement regulator at the NAPA store. If it is an internally regulated alternator, it needs to be replaced (if the regulator part cannot be serviced separately) before some wiring gets cooked.

The alternator has one wire. Would this be an indication if it is internally regulated?

Would anyone have a picture of the remote type regulator on a Superformance and/or know the approximate location to find it?

I found the associated diode in the fuse block.

ttmb · #5 (**permalink**) 12-08-2006, 09:32 PM

My Roush came with a 1-wire, so I suspect yours did too. It's internally regulated. I suspect that's where the problem with the jumpy ammeter arises. There's information on SCOF tech about how to install it and protect your car's wiring harness.

Tom

greg schroeder · #6 (**permalink**) 12-09-2006, 02:52 PM

This is my alternator.

Powermaster

greg schroeder · #7 (**permalink**) 12-12-2006, 02:09 PM

Quote:

Originally Posted by greg schroeder

This is my alternator.

Powermaster

Correction, sorry

According to Roush this would be the alternator on a 427R. It looks to be a GM alternator.

Powermaster 17294

I've now researched the problem.

The single wire from alternator in a round about way goes into amp gauge and then out to battery. The full load is being sent through the amp gauge. All that I talked with, including Powermaster, said don't do that.

My problem more than likely began because the wire out of the amp gauge going to the battery was loose and connected and disconnected at random. According to Powermaster when the wire is disconnected from the battery this is what spikes the gauge. It's a bad condition which is very hard on the voltage regulator inside the alternator.

My alternator tested to be delivering 15.8 volts. The internal voltage regulator is fried.

I ordered a new Powermaster 17294 from Summit. I'll install it and give a report as to the result soon. I'm reasonably confident this will resolve the issue. I'm going to bypass the amp gauge and use a volt gauge instead.

greg schroeder · #8 (**permalink**) 12-09-2006, 03:37 PM

Quote:

Originally Posted by ttmb

My Roush came with a 1-wire, so I suspect yours did too. It's internally regulated. I suspect that's where the problem with the jumpy ammeter arises. There's information on SCOF tech about how to install it and protect your car's wiring harness.

Tom

I'm a bit lost on the SCOF site. Maybe I'm just slow.

greg schroeder · #9 (**permalink**) 12-09-2006, 04:37 PM

Quote:

Originally Posted by greg schroeder

I'm a bit lost on the SCOF site. Maybe I'm just slow.

I e-mailed and a reply was quick. I figured out some stuff. Thanks SCOF

RedBarchetta · #10 (**permalink**) 12-07-2006, 06:26 PM

Way to go, Greg. Scorch the track, run a high 10, and you tweak your charging system in the process.

Easier than half-shafts.

-Dean

lineslinger · #11 (**permalink**) 12-07-2006, 08:14 PM

Also check and make sure the guage itself is properly grounded or if the ground wire to the guage might be loose, this happened on Smiths fuel guage in a Healy I used to have and drove me nuts till I finally figured it out.

ttmb · #12 (**permalink**) 12-07-2006, 09:38 PM

Your Roush motor should have a voltage regulator in the alternator, thus you should bypass (disconnect) the SPF's voltage regulator. My ammeter does the same thing. I just don't worry about it because it's intermittent. If you want to do something about it, there's something on the SCOF tech. site about how to damp it out. Probably caused by the rapid switching of the solid state regulator, I hear. I freaked out the first time I saw it - but there seems to be no adverse effects (so far). Everything's fine after about 5K mi.

Tom

ttmb · #13 (**permalink**) 12-07-2006, 09:41 PM

...or put in a voltmeter.

greg schroeder · #14 (**permalink**) 12-18-2006, 04:57 PM

The new alternator with new internal regulator works. I'm guessing my problem began due to a loose connection on the amp gauge. With it off it will destroy the alternator's internal regulator.

The Roush 427R does in fact have a Chevy type Powermaster 17294. It's a 105 amp alternator running through the 50 amp gauge. The alternator should never need to go all out given the equipment on the car, but if you have discharged battery the situation might not be good. The length of 10 gauge wire that runs all over the place probably isn't the best either.