I'm trying to do an S5 80 AMP alternator conversion on my car.

I assumed my car had an internal regulator alternator because my title says 1983. But the alternator in the car has an additional line on it.

Is this an externally regulated alternator?


Any advice will be greatly appreciated....

 

That's an internally regulated alt. That terminalprobably isn't used. Likely it is for testing either the winding/stator or the reg itself. It if you need any help with the S5 alt swap, let me know. I have done it before.

Kent

 

Ill take a bite on that one... needs help

 

For swapping an S5 or later alt, first take a look at this thread:

https://www.rx7club.com/1st-gen-archive-71/electrical-2nd-gen-alt-1st-gen-388262/

The major difference between the S5 and later compared to the S4 and earlier is a slight wiring change. You may need to use some washers for the spacer depending if your car is 12A or 13B and which spacer you have on hand.

For a 79, you need to first bybass the external voltage regulator to convert to the later style internally regulated alts.

That should get you started. If you have any questions, let me know.

Kent

 

Hi Kent:

I have read pages of great technical advice by you on this forum. Thanx!

Well there is a wire attached to that on my car. I will determine the wire color and let you know this afternoon (EST).

I greatly appreciate the help.

I have recently done the FC coils direct fire mod and the FC engine fuse block mod. This alternator swap would be the icing on the FB-cake.

Jon

 

Yeah, it mounts up beautifully. The FC spacer is just right.

I left that wire disconnected and tried to start the car. It seemed to be detonating and so I stopped. (loud backfires).

Maybe the alternator swap is okay, but my fuse block swap is not right. I test drove the car with the direct fire mod and that seemed okay.

 

No problem, Jon. Glad to help. It may be a ground wire or something. I'll take a look at the wirng diagram for an '83 and see if I can find it. The S5 alt is really nice. The voltage stays nice and constant even with light, blower, and so on running. On mine, I ran a new alt output cable. I used 8ga amp power cable from a car audio shop. Easy to do and better than using the 20+ year old stock wiring. I have done the FC fuse box and FC ignition as well. My ignition is using the 'transitor trick'. Works real good. Uses the FC ignitor for a stronger spark.

 

The 79 Alt has a 4 prong plug on the Alt end.

 

So when I looked at the connections at lunch time I was surprised I never noticed that extra wire is taped into the harness... I have no idea where it goes, I'll have to trace it back. My car has had a few previous owners... allegedly a rebuilt motor too...

I'll have to do the new alt output cable too... I used the stock cable and left the original ring connector intact and bolted it onto the stock post connector on the new alternator (see picture, look closely...)

Thanx again.

 

I looked in the 83 wiring diagram. It doesn't show that connection. It just shows the L/R plug and the output connection. Is there a label or anything on the alt that may help to figure it out? My guess is it's a ground of somekind. Usually alts get grounded through their mounts, though. What color is the wire?

 

I believe it's yellow with black stripe, but then its taped into the harness... I need to peel it back and follow it back... it's in the same harness as the engine sensors.... when I started the car with it unplugged I still got a reading on the alt guage... so it's not that...

(PS - I like the chekov radiation pic...)

 

Thanks. The pic is the core of the research reactor at the university I went to. Black w/ yellow sounds like it could be a power wire. I will see if I can find out what it is and get back to you.

 

After much head-scratching I have everything working now. I eliminated that line off the alt. Now running S5 alt with L connected to stock and S directly to + battery terminal, thru the FC engine fuse block.

Thanx for all your feedback.

Jon