Hi there, I was just curious if anyone on the forum has installed a later model RX alternator on their RX-2. I think mine is on it's last legs so I was going to put a later model higher output one on. The one I have is from a 1st gen. RX-7, my question is: what is necessary to change on the wiring? The RX-2 alt. plug has 3 wires while the RX-7 alt. plug has only 2. Is one for the external regular and not needed? I have an old Haynes RX-2 manual with some wiring info, but deciphering it is another question so I thought I'd ask here first and see if anyone knew off the top of their head.

What else is necessary?

Thanks,
Mike

 

this is what i did on my rx3. i disconnected the plug at the external regulator under the hood an with a test light, found the wire that was hot with the ign switch on, then connected it to one of the wires that goes to that 3 wire plug. removed that plug and replaced it with the 2 wire one for the first gen alt and put the "hot" wire i created in the plug for the top terminal on the alt.

here's links to my sources:

http://www.mazdarepu.com/board/viewt...?FID=1&TID=369

http://www.mazdarepu.com/board/viewt...?FID=1&TID=165

 

Hmm, now I'm really confused. I'm not sure REPU wiring translates over but I'll check since I have a REPU which already has this conversion.

Mike

 

Well, apparently two sets of wires need to be jumpered on the 6 wire plug to the voltage regulator but I have no idea which ones or why. Also couldn't get any normal readings off the 3 wired plug to the alternator. Man I wish I was better at wiring. Guess I'll check out my manual some more, but they just add to the confusion usually.

Mike

 

i couldn't make out which wires to jumper either from the pics. so i went to a shop that rebuilds alts and starters and asked them. look at the back of ur alt, on the 2 plug terminal on mine the lower one is marked with an "L". the other one needs a switched +12v to excite the stator to make it work. i think the other one is where the idiot light connects, i have nothing connected to mine.

 

Yeah I know what goes to those 2 plugs, just not sure which out of the 3 wires on the RX-2 alternator wiring harness to use and which to jump @ the regulator plug. I've noticed my regulator has been making an odd grinding/whining noise sometimes, so I think it may be the problem. I think I'll just get a new regulator and not risk burning my RX-2 to the ground trying to adapt a later model one, heh. Unless someone knows exactly what wires to jump, etc. I don't want to risk "testing" on the wiring harness.

Mike

 

doesn't matter which wire as long as it carries the +12v to the alt. unwrap the wires if u have to, i did.

 

You mean the regulator plug right? I tested all of them with the car running and 3 had between 12-14v. Couldn't seem to get any 12v readings off the alt. plug wires though, but maybe my idle wasn't high enough.

Mike

 

Im using a FC alternator in my RX-3...I eliminated the V/R...Used a test light to find a live wire from the V/R connector, ran a new wire to trigger the alternator's field terminal. The alternator has a 2 wire connector, I only used 1 wire and I cant remember if its the TOP or BOTTOM. I can check tomorrow if you need it. Again, you can use any ignition wire to trigger the alternator's F termnal.

 

ign switch on car off. unplug the regulator, on the male end of the plug find the one wire with power on it, mine is black w/ white stripe. connected this to the white w/ black stripe wire that's also in that same male connector, i removed these wires from the plug btw. the white w/ black stripe goes to the 3 wire plug on the alt, take it out of that connector and get the 2 wire connector for the other alt and connect it to the top terminal on the alt, the one not marked with an "L." if urs uses different colors to the alt, just us the ohm setting on the meter to check for same wire between plugs.

 

Ah, ok. Thanks, I'll try that. Does your AMP/volt gauge still work if only using 1 plug on the alt.? Mike

 

Ok I've figured out the first part. I was confused for a little while there because I had 2 wires on the regulator plug with 12v, one solid black and one white w/red stripe. Turns out the white one has 12v all the time so the black one is the correct one. Hooked that one up to another other black w/yellow stripe wire or the white w/black stripe wire and finally got 12v at the alt. plug. When I hooked solid black to solid black it blew the fuse so that had to be the wrong one. Anyone know what that white w/red stripe wire on the regulator plug does? It has 12v even with the ignition off.

Now to see if it's necessary to hook a wire up to the other lower plug or R as marked on the alternator. Suppose I'll try it without first and see what the gauges do.

Well, so far I haven't destroyed anything other than 1 15AMP fuse.. heh.

Thanks,
Mike

 

the white w/red stripe goes on the threaded terminal with the 8mm(5/16) nut.

 

I've got a factory wiring manual for 73 RX-2. Hopefully it is similar enough to 71 and 72 to be of use.

The 6 pin plug at the Regulator is called "A-04":

yellow-red // white-black // black
black // black-yellow // white-red


yellow_red goes to the dash warning light
white-black goes to the F terminal of the Alternator
black goes to the E terminal of the Alternator
other black goes the ignition switch via the fuse block, the fuel pump and the sub-zero switch.
black-yellow goes to the N terminal of the Alternator and the icle cut switch (for AC)
white-red goes to the ammeter and A terminal of the Alternator

hope that helps
Dave

 

I'm working with a 73, thanks. That does help. One odd thing is that I have no yellow-red wire at all anywhere, either on the regulator plug or alt. plug. Mine is very similar but looks like this:

WR WB Bl
--- --- ---
--- --- ---
Bl BY WR

So I have 2 White-Reds. Weird. Mike

 

Well I got it all hooked up and everything works great. I just ran the 1 12v wire to the L (horzontal plug) on the 1st gen. alternator after jumping it at the regulator plug. The alternator swap itself is pretty straight forward, I like the way it looks compared to that huge old one. The car seems to run a bit smoother but I haven't tested much yet, when it's really cold out will be the ultimate test as it used to go kinda haywire when it was chilly out.

In those links from the REPU forum someone mentioned they jumped 2 sets of plugs @ the regulator, I wonder what the other one was. Anyone know offhand? Perhaps the dash warning light, but what exactly does it warn -- low batt. or alt. not charging?

Oops I just re-read them and now it makes sense, I'll try hooking up the dash warning light tomorrow. No real way of seeing if it works though unless the alt. starts going bad.

Mike

 

This is great, it should go in the archives.

 

Would jumping the dash warning light @ the regulator plug have anything to do with my temperature gauge working? I just drove the car around a bit after the conversion and noticed my temp gauge didn't move at all. Perhaps I knocked something off somewhere, but just thought I would ask. I can't see how wiring for the regulator/alternator would have anything to do with the temp. gauge, but you never know.

Mike

 

Just an update: my non-working temp. gauge turned out to be old faulty wiring. I replaced some sections of it today and the gauge started working again.

I also hooked up the 2nd plug on the alternator "T" plug to the dash warning light but have no real way to test it since I believe that light is only triggered if the alt. voltage falls below the battery voltage.

Mike

 

if the warning light is on when you turn the key on
then goes out when the motor is started it is working
right. at least that is the way the one works on my
20b (not in the rx2)

matt

 

Bump for future use.

 

Whoa, I completely forgot about this thread.

 

Search button.

 

here is something good also that might help.

 

I have a Rx2 that was already converted to FB alternator but neither of the wires on the back plug were connected when I got it, the battery dies all the time and the alt isnt charging at all. Where is the plug in the factory position that I can hook the R Terminal to? Im pretty sure my Voltage Regulator is already gone also.