Alternator Help??
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Trailering
Joined: Sep 2015
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Alternator Help??
I have a 2004 F250 cc 6.0 psd with 137000 mile on it. I believe its time for a new alternator. When I start the truck the scangauge is showing 12v and dropping. After a minute or 2 its starts going up in voltage, then it jumps around from 13-14.2 volts. At the same time I'm watching the ficm main power and ficm line power. Main power stays between 47-47.5, the line jumps around from 13-14 volts. I have 2 new batteries.
Sorry for being wordy. I believe the brushes are starting to stick or its time for a new alternator. What do you guys think???
Sorry for being wordy. I believe the brushes are starting to stick or its time for a new alternator. What do you guys think???
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Trailering
Joined: Sep 2015
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Yea, I'm talking about after the truck starts. The voltage drops while the engine is running and then creeps up to 12v. Then after a minute or two the alternator starts to raise the voltage up, very slowly.
Lead Driver
Joined: May 2014
Posts: 6,545
Likes: 13
From: Virginia Beach VA
FICM logic power.
Its working as it should, as voltage increases the demand decreases... lots to do with glow plugs turning off around 90-120 seconds after the truck starts.
As long as you don't go below 9.5v with glow plugs on and it comes back to 13.8-14.2, your good. Step on he gas to give a little more RPM, but don't goose it because its cold. The added RPM will bring it back faster.
Its working as it should, as voltage increases the demand decreases... lots to do with glow plugs turning off around 90-120 seconds after the truck starts.
As long as you don't go below 9.5v with glow plugs on and it comes back to 13.8-14.2, your good. Step on he gas to give a little more RPM, but don't goose it because its cold. The added RPM will bring it back faster.
Lead Driver
Joined: May 2014
Posts: 6,545
Likes: 13
From: Virginia Beach VA
then go with a large unit, like the Neece-Leville 230amp unit. Also clean all the connections at the ground locations. Jack did a nice write-up on where they are located, search battery upgrades or something similar to find it. More likely he'll even post in this thread.
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Trailering
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Hotshot
Joined: Dec 2014
Posts: 17,833
Likes: 3,121
From: Jersey Shore
Yeah, that's pretty normal for the stock alternator, and the voltage floor has more to do with the battery (and the temperature) then the alternator. With the stock alt it's more zero sum gain due to the glow plug load.
Today is the last wedding show for my wife so I will have some free time after being tied up building displays and playing roadie so I will play more with my alternator work up.
Today is the last wedding show for my wife so I will have some free time after being tied up building displays and playing roadie so I will play more with my alternator work up.
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