Problem 1- Recently when pushing the motor to about 4500 rpms the volts start to drop, and all the lights get dim and the farther i push it the more they drop. It doesn't do it everytime though. I tightened the belt just to be sure and i sprayed some of that belt squeak stuff on it.

Problem 2- whenever i have both of my defrosters on the volts drop quite a bit and all the lights dim, this happened with my present alternator and with the previous two.

Problem 3- when at a light and i have the turn signal on the volts drop every time the signal flashes, they drop like 2 or 3 volts but that is 2 or 3 too many, my other friends cars don't do that.

I don't know what the problem is but it is really starting to annoy me. Hope someone can give me some ideas on how to test it or something i have access to a multimeter and/ or test light . Thanks

 

you have underdrive pulleys? try installing the smallest pulley you can get from march pulleys for the alternator .......

 

No I don't have under drive pulleys. Sorry I didn't say that in the original post. It's a stock 87 iroc 305 tpi, 5 speed with v-belts. Anyone have any more ideas. Thanks.

 

Sounds like a regulator problem in the alternator. Save up some bucks and replace both the alternator and the battery at the same time. Sometimes, one going bad can make the other go bad and you end up chasing your tail over time. Don't take some autoparts stores word that the parts are okay as gospel.

 

Well could that be the problem even if I have had the same problems with the 2 previous alternators i had on the car. I mean is it likely that i got 3 alternators with 3 bad voltage regulators.

 

You haven't mentioned the condition of your battery, yet. Is it in good shape, fairly new, sits close to 12 volts with the engine off? Connections clean? Wires free of corrosion?

A bad battery can hurt the alternator.

 

The battery is only about three months old and the terminals are clean I don't see any corroded wires or anything that could look like a culprit. The alternator is only a year and a half old. don't know if that makes difference.

 

You should chech out the ground cable going between engine and chassis. My car wouldn´t crank at all today not even with
the battery charger on(400Amps starting power). I found out that the ground cable had gone bad ( from the outside still showroom condition). Put a voltmeter between it´s to ends when you get somebody else to try starting the car. Mine dropped about 5 Volts
with the bad one and 0.2 V with the new one. This ain´t the same problem you have but I kind of think it could be related
(bad ground).

 

This past summer and fall I went through three alternators. The voltage regulators kept going out in them. Next my starter went out and right after that my battery went. Jza may be on to something! Just my $0.02 worth.

 

Well, when i get around to it i'll look at changing the alternator and see if that does anything for my problems. Yeah i have only had my car for about three years and this is my third alternator so far. I just hope this trend doesn't continue if it does happen to be the alternator. I'll check the ground wire also just to be safe. Thanks for the info guys.

 

Just a tought how to test it.
Buy a cheap voltmeter and wire it straight up to the battery, that way you should be able to see if it stops charging or if it´s about some loose connections or bad ground somewhere. You should even be able to do it with an testmeter if you just extend those measuring wires so they would go from the interior to the battery.

 

Do you know what amp alt. you have? If you are running 105 amp unit at a light with accessories all on the voltage WILL drop a couple volts. I have an 89 350 with 105 amp. and at night with all lights on and heater and especially if the fans are on the volt guage will keep time with the turn signals. As was stated here make sure all connections are clean and tight(check at starter solenoid lot of wires tie at that point) and that you are using a good quality battery. The rear def. is a current HOG. Not unusual to see a big drop when it is on. If voltage is normal when you are running you probably OK as far as the alt. is concerned. Did you install a larger than 105 amp alt.? Remember a higher amp unit will have LESS output at low RPM. Let me know if can help. Danno, 89 ROCK

 

Do you know what amp alt. you have? If you are running 105 amp unit at a light with accessories all on the voltage WILL drop a couple volts. I have an 89 350 with 105 amp. and at night with all lights on and heater and especially if the fans are on the volt guage will keep time with the turn signals. As was stated here make sure all connections are clean and tight(check at starter solenoid lot of wires tie at that point) and that you are using a good quality battery. The rear def. is a current HOG. Not unusual to see a big drop when it is on. If voltage is normal when you are running you probably OK as far as the alt. is concerned. Did you install a larger than 105 amp alt.? Remember a higher amp unit will have LESS output at low RPM. Let me know if can help. Danno, 89 ROCK