Alternator/Battery diag...

Caver Dave

Just holdin' it down here in BFV
Moderator
Joined
Mar 10, 2005
Location
Hooterville (24171)
After *only* 5 years, the Delco '1 wire" alternator I pulled from a pile at Toads (looked "least bad" of them all ;) ) seems to be getting flaky. I t was installed to get rid of the crappy Motorola setup & 20 miles of wire associated with it...

Pertinent info(?):
- Unknown origin, output, etc.
- Has worked fine for 5 years (lot's of high amp drain from winch, lights, wipers, & blower motor simultaneously)
- Over the past few months, my old redtop wouldn't stay charged? Figured it had just laid down on me 4 years :confused: (would return it to Costco, but can't find recpt. :rolleyes: )
- Installed brandnew "Nascar" (Exide) Spiral 9xx CCA 1 month ago
- Ran about 10 hours since install (Windrocks trip, short road trips)
- Cranked/ran fine last Sat.
- Last night, only clicked, fired with booster set, and drove to M&G
- Ignition seemed to sputter at + 1500rpm, and alt. belt sqawled for several miles
- After returning from M&G, wife says "BTW, your rear lights were on the other night"...but "forgot" to mention that! :mad: (more than likely, *the* battery drain)
- Measured 12.8 VDC at battery
- Fired it up and got the same 12.8 VDC at battery
- Alt. *sounds* rough as a cob! (squeeky)
- Pulled + lead off battery... engine continues to run
- Measured 14.1 VDC at alt. output, 11ish VDC on battery
- Alt. is quiet as mouse
- Reconnect positive lead, alt. starts squeeking, voltage still @ 12.8 VDC

Seems that the alt. *is* putting out good voltage, but may be breaking down (noise under load) and/or not pumping the amps? *OR* it's all working fine, but I have a short in the brakelight circuit? Will probably yank it off and haul to O'Rielly's for testing next week, but wanted to make sure I wasn't missing the obvious...
 
Put new belt on and adjust properly ( the source of your sqeal/sqeak) after you take Alt to where ever and have it tested.

Belt slipping will squeal/squeak and cause a low/no charge condition.

running a V belt, correct? If running a serpetine check yer tensioner.

Kevin
 
even though you have a new battery that does not mean it's good. I have gotten to many new batterys that with in a day to a month developed a bad cell.
With out starting your engine check your battery voltage it should be around 12.5 volts then turn on your head lights and check voltage it should not drop below 11 volts for at least 1 min if it does the battery is more than likely bad.

from what you discribed it sounds like the battery with the battery disconnected you have 14 volts with it connected you have 11 sounds like a dead shorted cell in the battery.
 
Good call CP! Turns out the battery is fried... yanked it for charging at O'R, along with the alt. Battery tested "Bad" and the alt. tested great! (go figure :rolleyes: ) Turned out the squealing was from the main belt running WP/PS... only loose. Will take the battery back tomorrow for replacement.

Thanks to you all for the tips! :beer:
 
Back
Top