Here's whats up. The higher the RPM's the higher my voltage is reading. (2k rpm's give me 14v +). The windsheild wipers work on one speed. But when I accelerate they go WAY faster. Everything is super bright inside. I'm afraid to turn my headlights on because I dont want to blow one. And when I shut the car off and pull the key out, the car runs for about 2 seconds after the key is out and then dies. This is all new. Car was perfect before. I took it to autozone and tested the alternator and they said it was good. I think I'm gunna test it a few more times but we'll see. Any advice/input/experience?

 

Pages 6 to 11 have different tests for the alternator. Problem could also be related to a short in the battery system.

http://www.teamfc3s.org/main/factory...CAL_SYSTEM.pdf

 

14v is kinda normal at rpm... but it should not go much higher than that. What is the voltage at higher rpms, when it is 'all bright inside?'

Voltage increasing with rpm up to 14v would be rather normal at low rpms, but above 2k rpm you should not see any more increase...

If the alternator checks out ok, maybe the sense wire is broken?

 

Okay i'm gunna do those tests now, I just got a new alt. belt because I saw a few teeth came off the one I have on there now.

After 2k RPMS The gauge shows over 16v. Autozone said it was over 17v.

 

Okay I can't go through the tests because I dont have a volt meter right now. Any other input?

 

The alternator should NEVER put out 16-17V. The job of the voltage regulator is to keep it right around 14V. Whoever tested it at autozone knows nothing (doesn't surprise me).

 

The two wire connector on the back of the alternator has to be connected up for the regulator to work.....

 

I do remember there being some kind of wire around my alternator that isn't plugged into anything. I thought it was for the plug that goes onto the thermostat housing. I dont have the plug there but I have seen other 7's with it. I think my 86 coupe has one. I dont know I pulled the motor out of it and unsure what to do with it.

 

If your alternator is an S4 then there is one plug on the back and it has two wires. One wire is black/white (B/W) and the other is white/black (W/B). Is this plugged into your alternator?

 

Then Autozone BS'ed you. 17v means you have a bad voltage regulator. Your headlights aren't the only thing you might fry. You might also fry your expensive ECU. I would try to keep the voltage under 15 or else don't drive it at all. Turning on the defroster, headlights, etc. will help keep the voltage down. The RX-7's voltage regulator is inside the alternator. You need a new alternator unless the 2 prong connector at the back of the alternator is unplugged. Go check. But you probably need a new alternator.

Replacement alternators are notorious for failing after a few days/weeks/months. Keep your warranty info and replace as many times as needed. Or maybe you'll get a good one on the first try. Who knows. Fortunately alts are easy to replace with nothing but wrenches, a rag and a pry bar to pry on the alternator to tighten the belt when installing the replacement. When you push in the middle of the belt with your finger it should deflect about 1/4"-1/2". Don't let it be too tight or too loose. I'd see if Autozone will yet you do it in their parking lot. Or if you know a reputable alternator shop then that might improve your odds of getting a decent one. Or you can upgrade to an FD alternator. Oh yeah, one last thing from experience: if a replacement alt seems to have a short, if the voltage drops and stays lower than the battery voltage, then disconnect that POS before driving to the parts store or you could destroy your battery too and the alternator warranty won't cover it.

 

I had my s4 alternator custom built by a local alternator shop and upgraded to 120 amps. It was still a direct plug and play.

 

Let this be a lesson to you. NEVER, EVER go to Autozone!!!! I could tell just by their commercials, their target demographic is people who don't know **** about cars, and their employees tend to not be much better. Never, my God, never. O'Reilly's and Advance are the ****, and Arnold Motor Supply is decent, great for when you need a weird part like a used exhaust valve out of a piston engine or if you need some bearings swapped. These guys are right, your voltage should never break above like 14.5V. 17V is ******* insane and you're lucky you didn't blow anything.