[johnpro]

It just seems like it's one crappy part after another anymore. It looks like my 100 amp PowerMaster is now a 30 amp LackOfPowerMaster. It's all of about 4 months old. At idle I've got exactly 12v across the battery cables ... enough to keep the car running, but forget about charging the battery.

I've had to have a jump 2 days in a row now to get home, both days with different batteries. I'm ready to toss the electric fan, the underdrive pullies, the PowerMaster alternator and go back to stock with all of them.

Can Autozone or Pep Boys load test these 1 wire PowerMaster alternators?

 

[66benchcoupe]

They probably could, but if its only putting out 12v then its bad. Mine puts out 14.5v at idle. Does the voltage rise at all when you rev the motor? Summit should be able to get you a new one in a day. I think the PowerMaster has a pretty good warranty. You could buy another one, return the bad one and then have an extra on the shelf in case you have this problem again. I'm thinking I should get a spare myself in case mine goes bad.

 

[MYTOYS]

Sounds like you have a bad one, should be more like 13.5 to 14 after only 4 months they should work with you on return.

 

[L20068]

At idle, no loads on, my alternator puts out 13.1... At 2,800 RPM my alternator puts out 14.2.. that's normal. 12 volts at all times is not O.K!

I work at kragen and yes, we can load test (bench test) these alternators. We can also hook our hand-held computer up to your battery and measure alternator output without you turning one wrench!

 

[johnpro]

Cool. There's a Kragen's just down the street from me. I'll take it over to let them check it before calling Summit for a replacement.

Thanks for responses, guys. I was pretty sure the alternator's bit the big one ... and I'm suppossed to be going to the Grass Valley Mustang show tommorrow night. Oh, well, my daugter is going, too, so I guess we'll just take her '69.

 

[autoxsteve]

John,

Been there, done that.
Manny, Moe and Jack will only tell you it is putting out current. They don't appear to isolate/detect diode trio or SINGLE rectifier diode failures.
You can repair this yourself. I have been round and round with Powermaster and would probably use them while iot is still under warranty (although you WILL have to wair AND PAY FOR SHIPPING BACK TO THEM).
I've got part #s for many of the internal components, which are available at most local auto-electric shops. These assemblies are relatively easy to repair. There are two prime culprits here, whic are 1) Diode trio - should be getting a faint ALT light (if you have that hooked up) and secondly, the regulator. The diode trio is less than $4.00 and the regulator is similarly priced. PM me and I will dig up my records on this dude...