PCM burning up my alternator?
03-10-2009, 11:56 AM
#1
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PCM burning up my alternator? I have put 7 alternators in my 99 t/a. Every time I get above 5000rpm it fries the alternator. The guy at the shop says the pcm is sending a signal for the alternator to charge *****-to-the-wall all the time but theres nothing he can do about it because it has what he calls a "hot rod program" in the pcm (my speed density tune maybe?). Is that possible? if so is there somewhere I can get a single post alternator for that year model?
03-10-2009, 01:31 PM
#2
Christ man it took seven for you to decide hey we maybe better check into this?
None the less. You need to do a lot of testing, the PCM only sends one signal to the alt through the exciter wire. No one changes this with a hot rod tune.
You need to get a good alternator on and running and see whats going on. The exciter should read around 10 volts with it running.
Have you ever seen all your dash lights come on while driving?
When the alt put out more than 17 volts it shuts ABS, ASR, airbags, all that **** turns off and the dash lights up like when you start it.
I had that problem. It was caused by a missing seal around the exciter wire and letting water get inside the voltage reg.
I still have the same alternator, I just didn't run it when it freaked out and only put a seal on it and been done with that problem.
None the less. You need to do a lot of testing, the PCM only sends one signal to the alt through the exciter wire. No one changes this with a hot rod tune.
You need to get a good alternator on and running and see whats going on. The exciter should read around 10 volts with it running.
Have you ever seen all your dash lights come on while driving?
When the alt put out more than 17 volts it shuts ABS, ASR, airbags, all that **** turns off and the dash lights up like when you start it.
I had that problem. It was caused by a missing seal around the exciter wire and letting water get inside the voltage reg.
I still have the same alternator, I just didn't run it when it freaked out and only put a seal on it and been done with that problem.
03-12-2009, 01:45 PM
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Christ man it took seven for you to decide hey we maybe better check into this?
None the less. You need to do a lot of testing, the PCM only sends one signal to the alt through the exciter wire. No one changes this with a hot rod tune.
You need to get a good alternator on and running and see whats going on. The exciter should read around 10 volts with it running.
Have you ever seen all your dash lights come on while driving?
When the alt put out more than 17 volts it shuts ABS, ASR, airbags, all that **** turns off and the dash lights up like when you start it.
I had that problem. It was caused by a missing seal around the exciter wire and letting water get inside the voltage reg.
I still have the same alternator, I just didn't run it when it freaked out and only put a seal on it and been done with that problem.
None the less. You need to do a lot of testing, the PCM only sends one signal to the alt through the exciter wire. No one changes this with a hot rod tune.
You need to get a good alternator on and running and see whats going on. The exciter should read around 10 volts with it running.
Have you ever seen all your dash lights come on while driving?
When the alt put out more than 17 volts it shuts ABS, ASR, airbags, all that **** turns off and the dash lights up like when you start it.
I had that problem. It was caused by a missing seal around the exciter wire and letting water get inside the voltage reg.
I still have the same alternator, I just didn't run it when it freaked out and only put a seal on it and been done with that problem.
The dash lights all come on when I start up the car but i thought that was part of the normal startup routine. It's never done that while i was driving. I don't think it's ever gone close to putting out 17 volts, the problem was the amps.
I was asking another guy about it and he said it's controlled from the PCM by a pulse modulated ground.
03-12-2009, 01:48 PM
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-edit- I lied, I just got a pioneer head unit, but it blew 6 of the alternators with the stock head unit.
03-12-2009, 02:34 PM
#6
It is, I'm just saying if it was a voltage reg problem and the volts went high the lights come on like that when you're driving. And your headlight bulbs blow out, your power windows actually go up and down at a decent speed, etc.
03-12-2009, 05:50 PM
#7
I've seen AutoZone put the wrong voltage regulator into an alternator more than once...I'd bet those alternators are the problem...the original that wasn't from AutoZone that died was probably just old and worn out or something.
Only thing you could do to the PCM that'd be a problem is messing up the installed options matrix...and most tuning software doesn't give you access to that. Installing a Holden program in a Chevrolet would be another way to do that...
Only thing you could do to the PCM that'd be a problem is messing up the installed options matrix...and most tuning software doesn't give you access to that. Installing a Holden program in a Chevrolet would be another way to do that...
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03-12-2009, 10:39 PM
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I've seen AutoZone put the wrong voltage regulator into an alternator more than once...I'd bet those alternators are the problem...the original that wasn't from AutoZone that died was probably just old and worn out or something.
Only thing you could do to the PCM that'd be a problem is messing up the installed options matrix...and most tuning software doesn't give you access to that. Installing a Holden program in a Chevrolet would be another way to do that...
Only thing you could do to the PCM that'd be a problem is messing up the installed options matrix...and most tuning software doesn't give you access to that. Installing a Holden program in a Chevrolet would be another way to do that...
03-13-2009, 10:24 PM
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03-30-2009, 12:19 AM
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Regulator burning up alt What i have seen is the resistor in the computer light circuit shorting allowing 12volt unresisted voltage to the light circuit will kill the alt. The thing you can do is hard wire the alt how you do this is take a ign on 12v in line install a 200olm 3wat resistor to the light circuit on you alt. this will eliminate the computer completely that is the was we do it on our stand alone off road engine work great. or you can buy a new ecm a lot more money
hope this works Chris
example
ijn voltage-----------200olm3w resistor-----------alt regulator L terminal
hope this works Chris
example
ijn voltage-----------200olm3w resistor-----------alt regulator L terminal