Alternator question, battery is discharging quickly.

[FerociousP]

Hey Zach, quick note.

For the sense wire, you could technically run a wire from the B+ on the alternator to the pin, but the voltage at that pin is used as reference for regulating... If say, your battery is in the back, the voltage read at the battery will be less that at the B+ "output" of the alternator... This could make the alternator regulate the voltage .1 or .2 lower than it normally would in stock config, or what you would prefer.

so, its good practice to have that sense wire be at least a little bit down the line from the alternator... If stock its hooked up at the fuse box, its probably best to hook it up there.

[FC Zach]

Originally Posted by FerociousP

Hey Zach, quick note.

For the sense wire, you could technically run a wire from the B+ on the alternator to the pin, but the voltage at that pin is used as reference for regulating... If say, your battery is in the back, the voltage read at the battery will be less that at the B+ "output" of the alternator... This could make the alternator regulate the voltage .1 or .2 lower than it normally would in stock config, or what you would prefer.

so, its good practice to have that sense wire be at least a little bit down the line from the alternator... If stock its hooked up at the fuse box, its probably best to hook it up there.

I sent my decrepit harness off with a request to have these wires run within the new one.

But yes, I have done that temporarily in the past.

[FC Zach]

Wasn't able to get a harness made however I did find a salvageable harness off a friend's parts car that I can make work and have done in time for DGRR. .

While pulling the harness off I looked for the illusive alternator connector that was thought to be on the charge harness and that I presumably had removed years ago. . That is not the case, I confirmed it's on the engine harness. Glad that mystery is solved!

[FC Zach]

I've already removed tape and unnecessary wires from the salvageable harness like CAS, trans switches, and oil pan sensors. Once LMS EFI returns my old harness I'll run my alternator plug/wires before re-taping.

[FC Zach]

I've been away on vacation for a week, I come home to see my package still hasn't arrived. . I sure hope it comes in within a reasonable amount of time to get the 7 drivable for the Gap!

[almoststockfc]

I would make other plans instead of hoping to get the parts.

[FC Zach]

Originally Posted by almoststockfc

I would make other plans instead of hoping to get the parts.

Not parts per se but my old harness I sent LMS, I will need to reuse a few things off it since Charles' spare wasn't complete. I sent Ludwig an email. . communication has been slow via email so if this falls through I'll drive the Celica again. We shall see.

[FC Zach]

Since finding that the S4 alternator wires (R & L) are actually in the engine harness and not the charge harness like thought previously, I traced the wires in an extra engine harness to the connector located in the passenger side footwell.

I depinned all but two wires on that connector and will run them to the S6 alternator, however I'll only be using the "L" terminal wire. I thought it would be wise to run the other wire for the "R" terminal in case I need to replace the alternator and decide to go back to S4. .

[FC Zach]

Originally Posted by FC Zach

I depinned all but two wires on that connector and will run them to the S6 alternator, however I'll only be using the "L" terminal wire. I thought it would be wise to run the other wire for the "R" terminal in case I need to replace the alternator and decide to go back to S4. .

After redoing the harness and finally getting things corrected to make a happy alternator I found I still had a battery drain. . . I took the alternator to get tested and it failed miserably but this was good news in a way (the search is over, I hope). Unfortunately it was just too late for my S6 alt the damage had already been done.

Reason why it was a wise choice to run that one additional wire? ? No S6 alternators in stock and were special order, S4 was next day So I got an alternator arriving in the morning just in time for me to have my car ready for DGRR.

Even after replacing the damaged S6, I don't think I'll be in the clear just yet. . . The "Charge" warning lamp doesn't illuminate with Key On/Engine Off and didn't illuminate while running with the damaged alternator. I'll check the bulb next.

[t_g_farrell]

It wouldn't be DGRR week without some drama Zach. See you in a few days!

[FC Zach]

Ha ha, see ya then!

[FC Zach]

Update. . The wires I added to support either S4 or S6 alternators do what they're supposed to.

With regards to this, it was because the S6 was toast. With the rebuilt S4, the idiot lights illuminated like they should:

Originally Posted by FC Zach

Even after replacing the damaged S6, I don't think I'll be in the clear just yet. . . The "Charge" warning lamp doesn't illuminate with Key On/Engine Off and didn't illuminate while running with the damaged alternator. I'll check the bulb next.

Not wanting to give up on the S6 alternator, I rebuilt it by replacing the bridge rectifier and voltage regulator this weekend. I took it to Oreilly's to have tested and it passed! Success! !



I'll be back in business without any battery drain (I hope!) and with a properly functioning alternator when I get the car running again. . .

[FC Zach]

Update, I received the harnesses I needed to get the car running this month and got everything all buttoned up. Since getting it running I reinstalling the S6 alternator and have periodically checked the battery voltage for any severe draining like before. . There is none, everything functions as it should so the car is back in business

Thanks to everyone for your input and assistance with this. I tend to make a mountain out of a molehill at times but that's usually because I have no idea what I'm doing and need guidance on some topics so thanks again to everyone for the assistance with this.