okay, i had my FD alt wired wrong in spring, blew up diode. Now wiring is ok, i put in S5 alt and it works fine.

However, what are options on fixing/replacing blown diode in FD alt? Where i could get it, fro how much etc?

 

You just replace the Voltage Regulator in the Alt... last time, i sued the rgulator out of an alt with a bad bearing, then threw the crappy regulator into the bad bearing alt, and turned it in for the core on my next alt!!

the Diode itself... an electronics nerd could probably just replace the diode, but I can't remember if you can get to it or if its sealed up.. been a while since i took an FD alt apart.

 

Yeah, I have never tried to replace it internally, but you could probably just use a 1N4006 diode externally (Cathode [bar side]) facing the alt.

 

ehm /me dumb

 

so seeing there is so much incorrect ways to wire this out there, what is the correct method? my car has serious voltage problems and its not getting any better. im going to go with the FD alt soon enough. it look like i can use the S4 bracket and whatnot (correct?) then how can the wiring be done wrong?

 

Most people swap the reference voltage with the status lead, because the S4 uses the opposite colors (or close enough) than the S6 alts.

This causes a discharge problem and tends to blow out the internal diode (again causing a voltage drain problem, even with the key off)

the correct way would be to not use the FC reference wire at all, and run a wire over to the battery + post for the FD alt reference.

the semi correct way to wire the FD alt would be just to make sure the referance and status wires are not mixed up and use the ignition feed that the FC uses as the refereance wire.

 

my batt is relocated so i guess i would have to run a wire from the pass. side bin to the alt. inorder to get that to work for me then...but the S4 bracket should work right? no ghetto rigging involved there? taking the pully off will be easy enough.

 

One thing that I've noticed on the FD alt (which works awesome, BTW), is that my voltmeter on the dash can get pretty low sometimes. If i'm at idle, with the lights on, blower at full, and stereo up, it hits damn near 12V on the guage.. but If I open the bin, and look at my Audiobahn Amp with the voltage display, the lowest I ever see is 13.8V, and as soon as the engine is moving a bit faster, it's right back at 14.4V. Note that the lights don't dim when I hit the brakes, even at idle.

Conclusion: I don't trust the stock gauge very much, and the voltmeter on the amp tells me everything is A-OK.

 

yeah my stock one drops to almost 8v at idle with lights on and whatnot....idle is 1000rpms. ...new alt time. i do have the underdrive pulley which doesnt help so im going back to the stock main pulley.

 

any time you are under 12.6 volts, you are running on battery power and not alt power

 

i am usually not making more than 12.6 volts unless im on the freeway.

 

That would be a bad thing. You need 13.5 volts to just charge the battery.

And that means your horse power is probably way down as well since the car is designed to run at the optimum power of 14.4 watts, and you would be having a weaker spark and reduced injector control (as well as lower fuel pressure) running at lower voltages.

 

Here is the CORRECT diagram from Silverrotor. First link is page with post, second link is downloadable picture

This is right for putting S5 or S6 (FD) alternator into S4

I just did this conversion with Silverrotors FD alternator into my S4.

https://www.rx7club.com/forum/showth...0&page=2&pp=15


http://www.teamfc3s.org/forum/attach...&postid=317950