TheSunKing

Hey all,

Got a 1980 RX-7. Took the alternator off to install a double-sheave pulley and I think I messed up the wiring when I put it back on. Usually I take pictures of things to make sure I can get them back together correctly, but I forgot to this time around.

When connecting the battery and when loosening the pivot bolt of the alternator, the post on the back of the alternator will spark a bit.

Here's the post I'm talking about:



View of post on back of alternator. The order I've got things is: insulating washer, wire from alternator, wire from harness.




Another view of the wiring.


If I'm reading the wiring diagram correctly, the black wire from the harness is from the positive side of battery, after a fusible link. I don't see the other wire on the wiring diagrams. I think the previous owner must have replaced the alt with an aftermarket unit. Did I mess this wiring up? Or do folks think this problem lies elsewhere?

Any help is appreciated! Thanks!

TheSunKing

I just realized I misspoke above. The order I had the wires in the picture above was [wire from alternator, insulating washer, wire from harness].
I tried rearranging things so that the order (from the alternator) was [insulating washer, wire from alternator, wire from harness] and immediately burned the main fusible link out. (T_T)
I don't get why that would be so different, considering they were connected to the same bolt in both cases... Completely baffling to me.

Also, I take back my statement thinking this was an aftermarket alternator. The Hayne's manual I have shows an external regulator, which was throwing me off. The FSM shows an internal regulator, which seems to match this alternator. The wire from the cylinder on the back of the alternator still isn't accounted for, though.

Is there any way to easily test if the alternator is faulty? The FSM has a couple of ways, but they all seem to rely on the alternator being connected to battery, which mine isn't, since it apparently likes to eat my fusible links.

I'm lost, folks. Any advice would be great.

TheSunKing

Okay, for the sake of anyone stumbling upon this thread with a similar problem to the one I had, here is my (hopefully) final update.

So the post on the back of the alternator wiggles a bit, right? And if it's dead center, it doesn't touch the casing. That's the key. The casing is grounded and the post is full positive battery voltage. Somehow, my first arrangement was intermittently grounding the post to the casing. In my second arrangement, I had put a bolt on the post first to secure the post in place, but that bolt created a solid contact between the battery and ground - which is why my fusible link immediately caught fire.

The proper arrangement is pretty much my second arrangement, but make damn sure that the insulating washer is the first thing on the post. It actually does a pretty good job of keeping the post in a secure position, so it's not like you need a bolt to keep it in position. After the washer, you can bolt on the two wires, order shouldn't matter. Again, the key is that nothing on the post contacts the alternator casing.

Here's a picture showing the final setup:



Hope this helps someone!