doomtrain

I just recently bought a new altenator for my fc because my old one pooped out. lets get straight to the point, since the install everytime i turn on the car the voltage meter reads 17 volts!(this is not normal) then when i give it some gas it jumps to 18 then back to 17. all my lights in my car pulses when im on the gas. then when i let off and let it drop under 1000rpms it goes away but the meter sits at 17volts. How do i fix this!!


1986 gxl
-new duralast battery
-new autozone altenator

WAYNE88N/A

Did you buy an OEM reman alt, or some aftermarket crap from the auto parts store?

Either the alt's voltage reg is fried, or the alt is not wired for the car's plug.

Please don't run the car with 17+ volts on her. You're going to fry something.

If you have a multimeter, verify the voltage at the battery terminals while she's running. If it is in fact 17+ volts, shut her down and get her fixed...

doomtrain

i bought a oem remanufacted altenator

Innovation

iTrader: (1)

Take it back to where you got it and have it tested.

doomtrain

so its the voltage regulator then? damn tha sux

Innovation

iTrader: (1)

Maybe but it's a good thing it's easy to remove!!!
O and by the way, don't go by what the gauge is reading in the car. After a bunch of years they are not so reliable. Use a meter at the battery terminals for a more accurate reading.

WAYNE88N/A

If they're gonna trade yours in for another for no cost, do that first...

Make SURE that they give you the proper one for your generation of RX-7...

If you still have problems after the "new" one is installed, we'll have to start digging into the wiring...

How did the last alt "crap out" on you?

doomtrain

k but why does all my lights in the car pulses like a fast heartbeat?

Innovation

iTrader: (1)

Not regulating properly. The alt should not put out 17 volts. Did you test with a meter? Or are you still looking at the gauge? If the lights are pulsing then that could be a differant problem.

3rdgenricereater

probably because there is way too much current and all of it is trying to go somewhere. suprised you have popped all your fuses and relays and melted some wiring yet. i really would take it out and have it tested on the machine at kragens instead of on your cars electrical system.

WAYNE88N/A

You could have a rectfier circuit out, which would allow an actual AC voltage wave into the system. The frequency of the pulse would be dependant on the alt's rpm, hence the pulsing you're seeing.

Innovation

iTrader: (1)

^^ Ditto

WAYNE88N/A

The really scary thing is that if you DO have an AC wave, the actual voltage in the system is going to be 1.414 times the voltage read on your gauge...

Over 25 volts, then. EEEEK

Innovation

iTrader: (1)

That would be a rare thing. The rectifier would have to be toast to do that.

WAYNE88N/A

No, you'd only need one phase of the three to do it (one diode shorted). Peak-to-peak voltage of an AC sine wave is 1.414 times greater than the voltage read on a meter.

If it is a bad diode, not only would you have the +17v you're reading on the meter, you'd also have a -25v (peak voltage) wave that's the same frquency as the alt's rotation. Hell of a thing to do to the ECU, lol...

doomtrain

ok right now im at work (radioshack) i just used my battery/altenator tester and i was right! at idle its at 13v but when i hit the gas my lights get incredibly bright and the tester reads 15v/16v. thats not cool man

WAYNE88N/A

Stop tormenting your car, man, or the repairs are going to be EXPENSIVE

How far away are you from home? If just a couple of miles, it might be safer to just disconnect the alt and drive on the battery...

doomtrain

how u do that?

WAYNE88N/A

Take that 8mm nut off at the top, pull the terminal end off at the big wire, and wrap it with electrical tape, or something else non-conductive. DO NOT let the terminal touch the engine, or any other metal, or you'll blow the main fuse...

Do this only if the battery is charged enough to get you where you're going. If you don't see at least 12v on your cluster's gauge with the key on, you might as well just run with the alt the way it is.

If you do decide to run on just the batt, keep all unnecessary electrical loads off. No head banging on the sound system, in other words.

Only start to freak if the voltage as seen on your gauge falls below about 10v.

doomtrain

thanks for the advice, do u know much this will cost me to fix?

WAYNE88N/A

Well, if you got a bogus part from stock, it should cost you nothing, unless you've managed to fry some things on the car...

Good luck, man