Alternator getting relatively hot!!
Thread Starter
Joined: Feb 2005
Posts: 716
Likes: 2
From: Minneapolis MN
Alternator getting relatively hot!! Just finished my ls1 swap and have been driving it some. I am using an alternator out of a 2001 corvette and its wired just like in the diagram below. The only difference is the wire that goes to PCM pin 52 is connected to switched 12V
https://ls1tech.com/forums/attachmen...e-charging.pdf
The alt is charging fine at 13.5 to 14V.
Thing is the alt seems to getting pretty hot even when run for a few minutes. Hot enough to where I cannot touch it. Is this normal?? If not, what could be the issue??
https://ls1tech.com/forums/attachmen...e-charging.pdf
The alt is charging fine at 13.5 to 14V.
Thing is the alt seems to getting pretty hot even when run for a few minutes. Hot enough to where I cannot touch it. Is this normal?? If not, what could be the issue??
Last edited by Schitzo; Aug 7, 2010 at 11:16 AM.
Was your battery at full charge before you fired it up? I assume that it was so no sarcasm involved... If the battery is even in the least suspect it could cause the alt to go into a full charge mode and stay that way ...Diodes could be failing and/ or there is an open circuit on the positive side of the system causing a low voltage drop that causes the overwork leading to the over heat... I had a 3g Ford alt that passed every test you could think of that had a bearing failure causing it to get hot and it never made a sound that would indicate that the bearing was headed out the door
Thread Starter
Joined: Feb 2005
Posts: 716
Likes: 2
From: Minneapolis MN
the battery is new and was able to start the car right away. When I realized the alt was getting hot, I charged up the batt for a few hours but that did not help.
Could you comment more on the diode issue? other ideas welcome
Could you comment more on the diode issue? other ideas welcome
Do the corvette alternators need a resistor put in-line on the switched 12v field wire (470 ohms) since the pcm controls it? If so maybe the lack of resistor is charging it wide open all th time. Just an idea.
Thread Starter
Joined: Feb 2005
Posts: 716
Likes: 2
From: Minneapolis MN
the turn on wire is connected to the pcm, the field wire is connected to switched 12v, the third terminal is connected to the alt batt post with an inline fuse. I drove the car to the exhaust this afternoon and watched the volt gauge and it stayed at 13.5. I have seen it go up as high as 14. So I am guessing its not charging "wide open"
Bearings going out will heat it up, but I suppose you would hear that.
Guess I would check the voltage at the output of the alternator, then try a clamp on ampmeter to see what type of current it is putting out. The voltage should be a volt or two above the dash voltmeter. Current draw will depend on load, but if it is anywhere near the alternator rating then you might have a short somewhere.
If amps and volts are good, pull the alternator and have it checked at the local parts store.
If all that is good just drive it.
Guess I would check the voltage at the output of the alternator, then try a clamp on ampmeter to see what type of current it is putting out. The voltage should be a volt or two above the dash voltmeter. Current draw will depend on load, but if it is anywhere near the alternator rating then you might have a short somewhere.
If amps and volts are good, pull the alternator and have it checked at the local parts store.
If all that is good just drive it.
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Teching In
Joined: Apr 2010
Posts: 1
Likes: 0
From: longview WA
corvette alts are pcm controlled. truck and f-bodys are not that i know of. my just need to swap the regulator. whats the amps coming out of the alt ? voltage may be ok but if the alt is charging at max amps its not going to last long. take it to a rebiuld shop have them see if they can get a reg thats non ECM controled. i'm not at work so i dono.
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