So it seems like no matter what I do, my tach stays on as a volt meter. I finally got my car to hold idle but I can't really tell what RPM it's in, so that I can adjust the idle to the proper specs. So let me break it down for you guys...

S5 Alternator in SA
-Wired the Black/White Stripe from the stock alternator plug into the 'L'
-Wired a fusible link from the 'S' to the 'B' with a 5A fuse in between
-Wired from the 'B' to the positive battery post, using a 6G wire.

From what I've read on doing this swap and from asking a couple mentors on this forum, this is how it should properly be wired. I am going to be changing my battery and alternator with a new one, since it couldn't hurt. But besides that, I don't know what to do. I installed a volt meter gauge, with wishful thinking that it would make my tach act like a tach again but no. Before when my idle was really rough, it would be around 5.5k on the tach. Now that the idle is more settle, it is all the way into redline, 8k+ on the tach. I didn't change anything beside charging the battery, so I do believe the volt meter is working properly, right?

Any input would be great. I want to start driving it, but don't want to yet until I know for sure it is properly tuned to specs. Thanks in advance.

 

My brother did the same thing with his SA and it seems to be working fine so far.

 

nm

 

When I first got my SA, it was showing the same symptoms as what you're describing. In my case, it was the original external regulator for the alternator that was causing the problem. I couldn't find a replacement anywhere so I decided to upgrade to an S4 alt.
It's very simple, what I did was take out the regulator, find the ignition wire used in the original regulator plug, and connect it to the top part of the connector on the alternator, and then capped off any remaining wires.
I've been running it this way for about a year now, and never had any problems. The tach works fine. The only thing is that you lose your volt meter. I am putting an aftermarket voltmeter to fix that problem though.
Here is a drawing that shows what I did, except they show it connected to the choke switch plug rather than the regulator plug.

 

Do you have a picture of the external regulator? And where/what it connects to? I believe I still have all the stock parts and I maybe I disconnected it by accident?

 

I don't have any pictures of the original regulator, but I have a picture of half of an aftermarket regulator that I tried. It didn't work. I don't know if you'll be able to make anything out from the picture.
You can see where it is supposed to be in the second picure. I've circled the plug which connects to the regulator (located on the driver's side fender, near the firewall). And I've circled the connector at the back of the alt. As you can see in the pic, I didn't use the original alt connector at all. The red line is the wire that I ran between both.
The only thing a can't remember is which prong I used in the regulator plug. But you can find that pretty easily with a tester.

 

I tried looking up what the stock external resistor would look like in the BlackDragonAuto magazine, my actual FSM, the online FSM, ebay, and yahoo/google image search and no go. But I think I may know what it is. Is it the small square that has the red/yellow/blue/black female spades connecting to it?

 

Yeah that`s it, it`s just a small square box with a connector on it. In my last post, the first picture is the aftermarket regulator that I tried (the black square box), and you can see the wires and the connectors just underneath it. My stock regulator was about half the width of that one though, and was more of a gold/brass kind of colour.

 

Is this it?

But I don't know what these plugs plug into, but they are off the above picture.


The only thing I had that was in the area with a similar plug was this

But it is really dirty and the plug off of the box is clean. Also the wire colors don't match. Does it connect further down the harness that I'm just not seeing?

 

What year is your SA, because my 79 regulator looked a little different. The regulator itself is about the same, but mine had a wires coming out of it that all ran to one plug (I circled it in the picture of my engine bay). It was a six prong plug I beleive, yours looks like the wire connect individually into the back of the regulator. I did have that extra two prong connector like your showing aswell though. I wish I had kept the regulator so that I could take pictures of it. I'm going to start my car tomorrow (it's in storage about 45min from here), so I'll take pictures of the old connectors and their location.

 

I have more of these copper looking boxes in the corner. I'm sure I have what you are talking about. My SA is also a 79. I'll try and take more pictures as well.

 

Here is a better picture of the location of the regulator. The big empty spot on the side where I drew a big red square is where the regulator used to be. I also circled the two plugs that connected to the regulator. they are the two white ones. One is a six prong (The one that has the electrical tape around it, I really need to clean up my engine bay), and the other a single.
Hope this helps

 

Oh, I do have the external resistor. You can actually see it in the first picture I posted, behind the one I thought it was. I believe it hooked up correctly but I guess I have to double check. Damn I regret taking these off for cleaning... arg.