In my '90 Vert, I was cruising the other day and most of the lights in the center idiot cluster came on ... at the same time the voltage dropped down just below 12. I drove it home and tested it. Car off I get a good 12.3 volts or so, car running I only get about 11 volts from the alternator.

Is there some sort of voltage regulator as a part of the alternator or charging system that could go bad and cause the alternator to not put out 14.4 volts? If so, where is it and how can I test? I'd hate to buy a new alternator and find out the problem was a 50 cent electronic piece.

 

There is an internal voltage regulator. Although I don't know if its replaceable seperately or not.

 

Alternator.

 

Umm.. i get 14.3 from my alt while running, i think 12.3 is to low, i bet if you drive around your battarie will die, if i jumped my car i could drive almost 20 miles with my old alt putting out like 9 volts

 

either your alternator is toast or the belt came off...

 

The voltage regulator is part of the alternator. Take it down to a local parts store and have it tested just to either eliminate or confirm the problem.

Just don't buy one from those guys. I went through THREE alternators before I finally bought a Bosch new. Was like $350 but hasn't given me a problem in almost 3 years.


JB

 

Behold, a resurrection. I wonder if there are any other opinions on this, and I need to get my car fixed ASAP. My problem is identical to boostd7's, down to the fact I have 1990 Vert. The lights NOT on in the idiot panel are airbag, brake, check engine. All the others are on (door, wipers, fuel, etc). The voltage gauge in the car, when running indicates below 12V, maybe 11.75. Normally it is around 13.5. I imagine that this will continue to decrease as I drive around with no alternator (or so it seems) and drain the battery.

The alternator belt is intact and properly tensioned. The christmas tree (idiot lights) just lit up last night, first time. Now on all the time (headlights on/off, radio on/off, etc). Previous, the only time I'd see ALL the lights go on was at night (lights on) under very high rpm, and they went out as soon as I shifted. At that time the forum opinion was that my alternator was on the way out.

Who has discovered a good source for alternators? Is it worth trying to get mine rebuilt/remanufactured?

Thanks for the help.

 

I have an FD alternator on my '88 'vert. Write-up is on my website, and the swap on an 89+ will be virtually identical. Good upgrade.

www.geocities.com/rx7_ragtop

 

rx7-ragtop. Where did you source the new pulley for the FD alternator?
Thanks for the post.

 

I got my pulley for my FD alternator off of an older pre-70s Delco alternator.

Jarrett

 

Maybe the question I should ask is this: Is there consensus that I'm going to buy an alternator? And since I'm buying one, I might as well buy an FD alternator because they offer 45% more output for a similar price, and fit in place with minimal modifications to the car and wiring. Further, the FD alternator will require measurement of the spindle, and then sourcing a pulley with the internal diameter of the FD spindle, and the external diameter of the FC alternator pulley.

Does anyone happen to know the FD spindle diameter? How about the FC pulley outer diameter?

I don't have 'the book', nor a caliper or good measuring tool for the pulley.

As always, thanks.

 

Boostd7.. Yeah, probably the alternator or regulator. My old 86 had a bad alternator which would crap out as soon as the engine bay warmed up. It would test fine cold, but not warm..

Anyhow, I went through 3 rebuilts as well until I got one that worked right. If you go that route, keep your reciept.. lol

On my 88 TII, I put an s5 alternator on and gets up to 15.1 volts instead of the old 13.6 from my old s4.

I say go with an FD alternator if you have the time to do it. Here is how to do it:

http://brfoundation.com/RX-7/alternator2.htm

 

I second that.

 

yes.

FWIW< I have a spare from a 90 if you need, $60 shipped.

Other than that, the FD alternator is a good upgrade, but the stock 89+ alternator is very decent for what it is. Now the older pre-88 ones are pretty pisspoor...

Dude, he hasnt had this problem for a long time :-)

(if you havent figured it out, look at the original posting date).

 

hypntyz7
I missed your post last night and ebayed one already. If I'm ever in TN with the car I'll make sure to drop buy and get a TII transfusion.
Thanks for the help everyone. I just went with the drop in FC alternator, the 'vert is my only car and I can't have it down for more than two days.
Happy Rotoring.

 

Off another Mitsubishi alternator with a big shaft. Dunno what it was originally on.

 

17mm shaft IIRC.