GEN light on,erratic volts to 18, poss pcm?
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GEN light on,erratic volts to 18, poss pcm?
hey guys, just purchased a 96 2500 4x4 diesel that is my dream truck except that it overcharges. Start it and the volt meter on the dash floates around 15-16v and then for no reason pegs out at 18v for a couple of seconds before coming back down. I pulled the alternator off and had it bench tested and it came out ok. Also i should say that i do believe it is not a guage malfunctioning because when my lights are on at night and the guage pegs, my headlights get extremely bright.( thats kind of nice actually
)
Bought a chilton book and as I understand the voltage is regulated in the pcm. Was just wondering if anyone else has had this problem and what it took to resolve it. I have to leave town tomorrow to go on a road trip and would like to take the vehicle if possible.
1. are there aftermarket pcm's that are of good quality?
2. Is it possible to convert over to an alternator with and internal
voltage regulator?
thanks guys--J
) Bought a chilton book and as I understand the voltage is regulated in the pcm. Was just wondering if anyone else has had this problem and what it took to resolve it. I have to leave town tomorrow to go on a road trip and would like to take the vehicle if possible.
1. are there aftermarket pcm's that are of good quality?
2. Is it possible to convert over to an alternator with and internal
voltage regulator?
thanks guys--J
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Joined: Mar 2004
Posts: 3,988
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From: Nebraska
Welcome to DTR
Yes, the PCM controls the voltage. What a lot of guys do in your case is to abandon the PCM for voltage control and add an external voltate regulator.
Don't drive it with voltage spiking to 15-18 volts. You are gonna fry something expensive.
Infidel is the electrical guru and he should be along shortly, unless he is still hungover from last nights festivities.
Yes, the PCM controls the voltage. What a lot of guys do in your case is to abandon the PCM for voltage control and add an external voltate regulator.
Don't drive it with voltage spiking to 15-18 volts. You are gonna fry something expensive.
Infidel is the electrical guru and he should be along shortly, unless he is still hungover from last nights festivities.
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Joined: Dec 2003
Posts: 14,672
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From: Montana
Geico, I'm too wise to get a hangover
Somewhat common for just the regulation portion of the PCM to burn out. The rest can remain fine for many years.
Disconnect the two small wires to your alt and tape them separately to prevent shorting. Hook up this setup, small wires can go to either terminal, it makes no difference. Any 12 volt regulator will work, the one in the picture may not even be availible.
Top terminal in the triangle must go to the switched positive.
Somewhat common for just the regulation portion of the PCM to burn out. The rest can remain fine for many years.
Disconnect the two small wires to your alt and tape them separately to prevent shorting. Hook up this setup, small wires can go to either terminal, it makes no difference. Any 12 volt regulator will work, the one in the picture may not even be availible.
Top terminal in the triangle must go to the switched positive.
Registered User
Joined: Mar 2004
Posts: 3,988
Likes: 7
From: Nebraska
[QUOTE=infidel;1277270]Geico, I'm too wise to get a hangover/QUOTE]
Wise due to experience? Or wise from taking the advice from those who have gone before you? The latter being the true source of wisdom, the former being from first hand experience and dones not qualify as wisdom. It is just plan common sense!
/QUOTE]Wise due to experience? Or wise from taking the advice from those who have gone before you? The latter being the true source of wisdom, the former being from first hand experience and dones not qualify as wisdom. It is just plan common sense!
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