Charging problems, 4 alternators and going... - Ford Powerstroke Diesel Forum
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post #1 of 4 Old 10-12-2010, 11:03 AM Thread Starter Rookie
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Charging problems, 4 alternators and going...

Hey Guys,

I've got an 02 excursion 7.3 that has been plagued with alternator problems. I'm now on my 4th alternator. I just got back from a 1000 mile trip and was able to limp it home on batteries and a brand new autolite alternator. The trip down to LA/San Diego went well but the following day I noticed a humming sound. I'm familiar with this humming sound being related to the alternator so I immediately pull out my multi-meter and I probe both batteries while its running. I get a 12.20v. Had my buddy rev it up and the voltage didn't move.

I ran to Kragen and had a choice between rebuilt and new. I went new for $25 more and a lifetime warranty. Replaced the alternator in the Disneyland parking garage, took 10 mins. I start her up and i get 12.7v. (I just today found out that there is a 60 second delay in the alternator turning on). I didn't know that at Disneyland but I shrugged it off and was happy I was getting a partial charge. I didn't want to sweat it too much and have my family worry so I closed the hood and drove down to San Diego. No issues, I was up and down Rancho Santa Fe/San Diego hills with absolutely no issues until the trip home yesterday.

Just as I peak the 4400ft 6% Grapevine pass my battery light starts flickering. ****! I make it down the grapevine and I pull over. I probe the battery and I see 12.02v. I've got about 300 miles to go I decide to run her home and not shut down. I pulled over the next 100 miles and I see 9.05v. At this point my windows/radio/cigarette lighters aren't working. I'm thinking I might not make it on just batteries alone so I ask for the nearest parts store and it's 30 miles away. I decide to call Aaron (nation) who is about the only powerstroker i've got a number to try and diagnose. As I hang up after leaving a message, I notice my a/c blower get stronger. I step outside and probe the batteries and the alternator is giving it 12.6 - 12.7. I decide to run the 200 miles all the way. The battery light stays off up until 2 miles from home and it starts flickering again. We made it home.

I woke up this morning. Disconnected all battery wires and load tested the battery (trying to keep it simple at this point). Batteries both tested well on a 10 second load tester. Cleaned all 4 terminals and connectors which were somewhat dirty. I start her up and i get 12.7.... after 60 seconds it jumps to 13.90v at the alternator and 13.84v at the driver side battery. (Per nation, I check the 2-wire harness running to the alternator and all seems ok, but I have yet to peel away the entire loom that runs along the engine block to check for any open/shorts.) So the battery light is gone and i'm now getting 13.8v on a cold engine. I get in to rev the engine and when I pass about 1800rpm revs the battery light comes on and flickers and then shuts off as the rpms drop. Give my pop a call and he says could be the belt slipping. I kinda agree but I don't see the belt looking loose when I rev it. No belt bounce or anything. What do you guys think? Shot brand new autolite alternator?

Thanks in advance.

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post #2 of 4 Old 10-12-2010, 11:56 AM
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I checked mine the other day and mine charges at 14.03 to 14.04 and my alternator is 8 months old. Checked my dads original 106,000 mile one and his charges at 14.0. I can't see you going through that many alternators though but it's possible.

2001 F-250, 6 speed trans, BDP Tunes, Autometer Ultralite gauges
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post #3 of 4 Old 10-13-2010, 11:27 AM
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you get some good ones, you get some bad ones... Had one on my truck, would cause a 'hic-up' from time to time. Both had been replaced by me, one went bad, replaced them both (under warrentee), and now hic-up gone, and no issues.


'99 E350 DRW Stahl 11' util box van, 7.3 PSD, stock. 138k SOLD

'00 F350 extcab, 9' utility bed, dually 221k

E'99 F250 extcab, S/Bed 211k

'00 Excursion Limited, 7.3PSD 281k

'84 Chevy K-30, 6.2L TD, woods/trail beater. 141k

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post #4 of 4 Old 10-13-2010, 07:41 PM
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you should be charging 14.x. something in your regulator is effed. See how much its dumping to ground.

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