Ok here's my problem, if any one can help out I would really appreciate it.. When I have my headlights on and stop at a red light (so the brake lights are on too) My volt meter drops down to 13 sometimes lower.. When I turn up the radio (2amps, 1 10'sub) it drops way down, with litghts on and brake lights.. I did not start doing this untill about a month ago, and it doesn't always do it, but most of the time it does. (and it's only really bad when it's in drive (when th rpms are lower, about 600rpm) I have changed the battery and the alternator and put in a cap for my amp.. Don't know what else it could be besides maybe the wire coming from the alternator... Any guesses??? Thanks everyone....

 

what alternator did you put in. you might want to put in an 80 or 100 amp, thats if it wont screw up the computer. i dont know much about computers so double check this.

 

My cars doing the same thing, put a load on the altenator at low rpms, and it'll bounce. Its probalby a bad regulator in the altenator. Take it out and get it tested. Or ignore it till something bad happens, thats my current strategy. It does look dorky at traffic lights with the headlights going normal to dim all the time...

 

mine doesn't bounce tho, it just goes down.. if I put it in nutral so the rpms go back up some it sits at 13volt.

 

Dream,

Are you using an underdrive sheave? I didn't see it in your mods list, but...

If not, your load is exceeding the output capacity at that RPM. You can either resuce the load, or increase the output. A 140A alternator would be a good start.

If you used a remanufactured alternator, you really don't know what you have, despite what the case markings might indicate. Common remanufacturing processes mix up all the parts so that you may not have the correct stator, rotor, or rectifiers for the case. Your presumably 104A alternator may have a 37A stator - another good reason to rebuild your own. You can get a high current conversion kit to upgrade your existing alternator if you want.

 

Vader.. Thanks. where can I get a 140A alternator, I didn't think you could get a bigger one for these cars without making your own brakets.. (I say that because ive seen people use alternators out of diffent cars that hav a higher amp rating and they fit differntly..)

 

o yeah and im not using any underdrive components..

 

At that slow of an rpm, with that much load it simply can't keep up. The only problem with this will be if you do it often and/or for extended periods of time--it can drain the battery. A bigger alternator will help. An overdriven pully will help. I agree Vader, rebuilding your own alternators is better than buying a rebuild--I do my own. I rebuilt my camaro one just a few weeks ago. Brushes, bearings, and a regulator(they don't give those away anymore). It's just a 63 amp model, but it's lasted quite a while(was in the car when I bought it in 94') A 'cap' won't help the alternator load--the alternator has to keep the cap charged. Maybe the engine idle rpm has dropped slightly(for whatever reason)--a small change in rpm at idle can have a big effect on charging.

 

I was thinking about the idle.. It used to idle around 650 700 in drive, now it is between 500 and 600 but i have been having idle problems too.. this all started around the same time.. When I crank up my car in the morning it would idle at like 1300-1500 before going into closed lop(or open which ever it is).. thats way to high( I put it in drive and the damn thing peels out.. I adjust it when it has already warmed up, to like 800-900 in park, then shut the car off and it will idle at like 1200 for a few then drop down to like 550 in park(to low) it won't stay just right.. Something is up with it, I have never had this problem before.. Any opinions??????? THANKS EVERYONE

 

You also keep saying, under that load... I would think that the head lights and brake lights being on at a stop light would be a normal load... It does it with the stereo turned all the way down... And like I said It never did this even with the radio turned up untill about a month ago..

 

This may be completely irrelevent, but has anyone had any problems with their actual guage not reading properly? I had a dead alternator today, and replaced it, everything good. The only thing is that my volt meter only reads 13v, and I checked voltage at the battery when it's running, and am getting a strong 14v. Is there some easy fix to make the guage read correctly that anyone knows other than putting in a more precise aftermarket guage? Thanks!