4u 2 nv

iTrader: (29)

My gauge has been showing very low voltage...like in the red. I put i meter on the battery and it said 12.2ish and the alt said 12.4ish...which is low. Went and got another new alt and out it on. Right out of the box the guage is perfect, 14.5 off the alt and 14.1 at the battery. Let it idle and it dropped down to 12.4 at the alt and 12.2 at the battery with a low gauge reading again.

So..i put the old one back on. And it did the same thing. for the first 5 min it read perfectly at 14.5 at the alt and 14.3 at the battery. Let it run for 10 min and checked it again. Now is back into the twelves again and back in the red on the gauge. The wiring is fine, there is only a small drop from the alt to the battery. IM LOST

Some friends are thinking its the underdrive crank pulley..any thoughts?

rkinney

That could be your problem. The smaller crank pulley will slow all your accessories down. I put the overdrive alt. pulley along with the crank pulley to speed the alternator back up. I have never had your problem. Did the problem start after you put the crank pulley on?

4u 2 nv

iTrader: (29)

it was on the car when i bought it...the alt pulley is a stock size pulley

koolaid_kid

iTrader: (21)

I agree, when you have an underdrive pulley on the crank, you need the overdrive pulley on the alternator. I ran mine without the overdrive pulley for about a year, then the battery died while I was idling in line at the track. Some bozo had dropped his tranny on the track so we had to wait a long time. I installed the overdrive pulley, and no issues whatsoever since then (5+ years).

4u 2 nv

iTrader: (29)

where can i get just the alt pulley? any thoughts?

is it odd though that the car ran for 10 odd minutes at over 14 volts and gradually worked its way down..you would think if it was not charging enough it would do it all the time.

koolaid_kid

iTrader: (21)

When you rev the engine, does the voltage climb back up?

ORedRoc4

iTrader: (15)

Maybe check grounds and then call it a day, if it hasnt died on you, i wouldnt worry about it too much. You could always go back to the stock pulley. You think youll miss the added HP over the drivability? I doubt it....

-justin

4u 2 nv

iTrader: (29)

yes it does...but only to around 12.8-13.1 at the alternator..thats just enough to keep the battery charging..it still doesnt even make it to the halfway mark on the dash gauge (but im not using that has a end all be all)

When you are at a light at night. The lights can get so dim it can be hard to tell the are on.

koolaid_kid

iTrader: (21)

It should climb up to around 13.5 tops. You may have a general charging problem instead. The best way to troubleshoot would be to put the stock pulley back on (along with a longer belt) but you probably don't have the stock pulley, since it came with the underdrive pulley on it.
I would start by pulling the alternator and taking it to an autoparts that will check it for you. Almost sounds like a part is overheating after it warms up.

94LT1Bird

iTrader: (4)

u can get an overdrive pully at thunderracing.com

blackz6sp

iTrader: (11)

I had the same problem, I bought the car with an underdrive setup on it, I went to a local business rebuilds starters and alt. I asked them for the smallest pully they could get on my alt., they hooked me up with a free pulley. I put a 1" shorter belt on, problem solved.

4u 2 nv

iTrader: (29)

well its now done the same exact thing on three diff alternators. The alternator that was checked is this one and it checked out perfect (amps and volts).

and i do have the stock pulley, just need new bolts. An underdrive on these cars bolts to the stock harmonic balancer so i still have the OEM one.

blackz6sp

iTrader: (11)

It's still gonna be rotating slower because of the crank pulley, just find a smaller pulley for the alt.

koolaid_kid

iTrader: (21)

Yes, I have an underdrive pulley also. It uses slightly longer bolts, since it bolts to the end. You just need slightly shorter bolts. They are not that expensive. If it solves the problem, just buy the overdrive pulley and you will be good to go. Best of luck.

1slowZinthe513

iTrader: (10)

Do you have the part number and where to buy the smaller pulley for the alt? I need one as well.

koolaid_kid

iTrader: (21)

Someone already posted that they were available at Thunderracing:
http://www.thunderracing.com/catalog...vid=4&pcid=111

blackz6sp

iTrader: (11)

Like posted above either Thunder Racing, or try a local shop that rebuilds alt. and starters thats where I got mine they didn't even charge me for it.