Posted June 8, 201213 yr I've been having issues with the PCM messing with my voltage, so I spoke with Josh Over at mechman and he told me to see what happens when I disconnect it.. this is what happens.. this is something he has NEVER seen. As I say in the video it is not a self exciting alternator.It is a brand new 320a alt.
June 8, 201213 yr Author I forgot to mention this is a PCM regulated car, so the PCM controls the output of the alt.
June 8, 201213 yr well its working lolpretty odd stillmy buddy had a lot worse issues with his MM, highest it'll charge is like 13.5. they've done nothing to fix too.hope you get it figured out
June 8, 201213 yr Author I only did this to see what would happen if I were to externally regulate my alt, this is just a weird ass occurrence. Josh suggested this to see if anything funky would happen..
June 8, 201213 yr Damn, thing is defying laws of physics. Maybe you should disconnect the fuel lines and see if it keeps running on nothing? LOL, J/K... I gotta ask, was the alternator disconnected before the car was started? I could see where it might do something hard to explain like that if it was disconnected after it was started and charging already. If you started it after disconnecting it then I definitely have no good explanation for you. The voltage seemed to be pretty good and steady with it disconnected tho, maybe thats a good thing. Odd but good.
June 8, 201213 yr The other connection on the alt (covered by rubber jacket), is from the PCM?If so, then I'm going to guess it's producing 14v. If that's the case, I wouldn't do anything that requires lots of current since your main power wire is disconnected, and it'll try pulling it through the small wire for the pcm.At least that's my guess, but it's hard to really see what all is connected.
June 8, 201213 yr Author I disconnected the harness from the alternator and started it, Josh from mechman told me in some newer cars without the harness connected and the PCM controlling the alternator some bad things can happen to them. I am about to call him and see what he says.
June 8, 201213 yr Author The other connection on the alt (covered by rubber jacket), is from the PCM?If so, then I'm going to guess it's producing 14v. If that's the case, I wouldn't do anything that requires lots of current since your main power wire is disconnected, and it'll try pulling it through the small wire for the pcm.At least that's my guess, but it's hard to really see what all is connected.That wire to my knowledge just runs to my battery up front. The Harness is what tells the alternator to turn on or off or modulate the voltage.
June 8, 201213 yr The alt has an internal regulator set at 14 volts.I had issues with an aftermarket alternator. My vehicles PCM wasn't able to control the voltage. I wired up an external regulator and bypassed the PCM and it works perfectly.
June 8, 201213 yr Author The alt has an internal regulator set at 14 volts.I had issues with an aftermarket alternator. My vehicles PCM wasn't able to control the voltage. I wired up an external regulator and bypassed the PCM and it works perfectly.I will probably be externally regulating it anyways.
June 8, 201213 yr The alt has an internal regulator set at 14 volts.I had issues with an aftermarket alternator. My vehicles PCM wasn't able to control the voltage. I wired up an external regulator and bypassed the PCM and it works perfectly.I will probably be externally regulating it anyways.You will need to have it sent back to Mechman for an external regulator setup.
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