broke down 96
Thread Starter
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Tuned
Joined: May 2004
Posts: 289
Likes: 1
From: Walton, Ky
Its not charging. I'm getting 12.25 volts shut off and 12.8 volts running. I changed alternator and getting the same. What controls the voltage regulator, is it on the pcm? I'm cleaning grounds now.
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
The voltage regulator is in the alternator. Did you wait until the GPs had cycled off (the GPs themselves, NOT the WTS light) before checking the voltage?
Oh wait, you had that hot GPR short as well, right? So is the GP relay decommissioned for now, and not in the picture?
Oh wait, you had that hot GPR short as well, right? So is the GP relay decommissioned for now, and not in the picture?
Thread Starter
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Tuned
Joined: May 2004
Posts: 289
Likes: 1
From: Walton, Ky
It has a new glow plug relay on it. I checked it both ways withe it hooked up and unhooked. I put my alternator on dads 97 and it charges. It won't charge on my truck. It will maintain 12.25 volts but won't charge to 14.3 I'm seeing on his.
Thread Starter
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Tuned
Joined: May 2004
Posts: 289
Likes: 1
From: Walton, Ky
Okay so I messed with it for a while tonight until I started coughing to bad to stay out. I took the alternator we put on dads truck 2 weeks ago and stuck it on mine. This was the reading on his truck.
Now this was the same alternator on my truck 5 minutes later.
I cleaned the 2 ground spots on the driver side fender, the grounds on the core support and fixed one broken one, cleaned the grounds on the passenger side fender and the one on the firewall. Tomorrow Im going to clean the 2 engine grounds after my shop floor dries. Im also going to swap batteries as well just to see if maybe I have one doing something stupid even though they both pass the load test. Other then that it runs with out acting stupid but if I run my plow I pull voltage way down. I hooked the Glow plug relay back up and it seems to be acting normal.
Andy
Now this was the same alternator on my truck 5 minutes later.
I cleaned the 2 ground spots on the driver side fender, the grounds on the core support and fixed one broken one, cleaned the grounds on the passenger side fender and the one on the firewall. Tomorrow Im going to clean the 2 engine grounds after my shop floor dries. Im also going to swap batteries as well just to see if maybe I have one doing something stupid even though they both pass the load test. Other then that it runs with out acting stupid but if I run my plow I pull voltage way down. I hooked the Glow plug relay back up and it seems to be acting normal.
Andy
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
So you got this reading ^^^^ with the engine running, and the glow plug relay DISconnected?
When you load tested the batteries, did you have them isolated from one another (disconnect one negative cable)?
When you load tested the batteries, did you have them isolated from one another (disconnect one negative cable)?
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
^^^^^ D'OH, yeah, I forgot about that stupid series connection with the bulb. Disables a perfectly good alternator.
Also check that connector on the top of the alternator. Bad connection or damage to the terminals there is not uncommon, and will do the same thing.
Also check that connector on the top of the alternator. Bad connection or damage to the terminals there is not uncommon, and will do the same thing.
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Thread Starter
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Tuned
Joined: May 2004
Posts: 289
Likes: 1
From: Walton, Ky
The light has been on ever since I got the truck. I didn't really pay attention when I swapped the alternator. The reading above is the same with the glow plug relay hooked or unhooked. It was also done with both trucks at operating temps. Can you guys tell me which wires do what on the alternator? I hope to figure this thing out tomorrow because its really irritating me.
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
Here's the EVTM diagram - http://userpages.chorus.net/elephant/EVTMCharging.pdf . First thing I'd check for is voltage at that yellow/white wire on the top connector.
Thread Starter
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Tuned
Joined: May 2004
Posts: 289
Likes: 1
From: Walton, Ky
Okay so its now charging 14.4 volts, the batteries check out and I've put 45 miles on it today. I'm guessing the plug on the alternator wasn't making a good enough connection. I had unplugged it when I was trying to find the short last week. Once I probed the plugs with my volt meter pushing down on the wires it jumped to 14+ volts. I want to thank you all for the help. I haven't been messing with the powerstokes long but I'm slowly learning. Hopefully this fixes my issues.
