Im confused, i just installed my engine in my new shell and for some reason my alternator gets really hot after hooking the battery up, even if the car isnt running.. Can you guys tell me why this is happening?

 

Its an s5 shell with the S4 T2 swap. The alternator is also an S4.

 

there you go,, you have the Alt R field wire hooked up instead to an S signal


its to do with a change in the alt field type between s4 and s5 and subsequencent change in the s5 wiring

s4 alts have an R field wire,, and it goes to the igniton switched power ( black with white stripe )

s5 loom instead has a S wire ,, that is the alt for the s5 uses an S wire which is triggered always live from the battery

you need to pull instead a black/white wire over and plug it into the top of the T plug on the s4 alt and all will be fixed
( unless the alt is burned out already )

 

thank you bump start i looked in the 2nd gen archives and found the alternator thread. So i just have to run an ignition switch wire to the top of the T plug.. But do i just leave the S wire disconnected?

 

Correct.

 

Thanks Nate!

 

Anybody care to explain how the alternator is going to get excitation voltage if only switched power is going to the top of the TEE shaped connector?

 

at around 3000rpms?

 

and what is wrong with hooking it up as mazda did?



looks like black with white from here,,,,,and it seems to have worked for me for nearly 20 years

 

I don't quite get your drift. There's nothing wrong with wiring it like the stk car. BlackWhite on top for the regulator and white/black on the bottom from the COIL of the alternator relay in the CPU via the Meter fuse. No warning light assy involved directly on a series four. Talking series four.

The image in the post is slightly wrong in that it shows the L wire being fed by the DASH which is something that bugs me a bit 'cause its misleading. Slightly misleading on a series four car. That white/black wire is the excitation voltage for the alternator and should show appox 1-3vdc when backprobed with the key to ON, engine not turning over. It does not have a sole function of making the idiot lights come on when the alt is not spinning.

 

in my first response it is assumed he already has wired that white/black L wire up as there is no change there between s4 and s5


if you hook up the black /white to top of the tee and nothing else the alt will still turn on first time you lift revs to 1500 rpm

this is how most do it in older RX changing form external reg to internal reg 12at/s4 alt
else there is complications of adding a latching relay to get the signal polarity correct at the light

 

well i can tell you guys that i fixed it... what i did was run the ignition to the top or the "T" and the bottom part of the "T" is hooked to the wire that doesnt have constant power... And it seems like its working fine to me..

 

It's self exciting itself with the fifteen hundred rev. In normal stock car operation the only current to the field of the alt (initially) is thru the L wire being fed by the coil in the alt relay (inside the CPU on a series four car).

The top wire should be feeding the regulator/transistors but not outputting to the field until the alt is actually rotationg and the diode trio is now putting out. The diode trio feeds the field from then on.

The alt relay in the CPU then relaxes 'cause the voltage on each side of the alt relay coil is the same.

Three cheers for Casey Stoner the top MOTOGP rider (AUS).