Take your car to an auto shop. Have them test it under a load. Mine tested good at 3 DIFFERENT auto parts stores. Then I took it to a shop and it tested bad under a load.

 

An old trick to see if an alternator is working is to stick a metal screwdriver to the rear shaft and see if it is magnatized. If it is making juice it makes an electromagnet and the screwdriver will stick to it.

 

I will have to take it to the shop and have them look at it.
That does sound like an easy test

 

So I am still having a problem. I just killed my 3rd batt in 3 months and tested the alt 4 times in a row and it passed. The batt has 12.51v so that's bad. It is looking more and more like a short some where

 

what amp rating is your alternator?

I'm using a 70A alternator replacement on my car and it's barely enough to keep it going. Every month I have to hook the battery up to the charger and bring it back to full.

Also it's a 1 wire alternator, and for some reason doesn't charge until the car has revved over 3000rpm which is a bit wierd.

What I'm going to do is buy a $5 multimeter off ebay and run it from the battery to the dash and set it up there so i have a constant readout of the voltage and can see if it's charging or not, i don't quite trusts the dash cluster gauge.

 

It might be better to get the higher amp alt. i know that alts don't put out peak charging until higher rpms

 

yeah i'm gonna get one of the 200amp ones from the states which i think has 120a at 800rpm idle.
Cheaper to buy it over there and ship it (shipping is half the cost) than it is to buy a 70amp one here.
damn Australia!

 

Heh I agree, been taking advantage of the high AUD this year myself

 

I think mine is a 140amp I need to check it again

 

Yeah I want to get a 383 stroker kit and rebuild kit from the states, but the shipping just kills you. $600 for the kit, $500 shipping, its ridiculous.

 

True, but I'm finding that even after eating the shipping cost, it's usually STILL cheaper than buying stuff locally. Unless it's something really massive like a block, heads etc.

With the current exchange rate, my rough rule of thumb is take Summit's price and add 80%. That's about what the shelf price for an item will be here from a large parts house (eg Rocket, Superplus, Engine Masters etc). If I can get it OS for less including shipping, I'll do that.

 

Alright I think I found the problem. When the alt is not under load it is generating about 14v under a load it drops to around 12v or less. Sounds like the regulator is bad or the diode which in turn is shorting out the Batt. I also did a different test where I think someone on here sujested is while the car is running disconnect the neg batt cable and see what happends. Well when I did the voltage dropped and the car began to shutter.

So next question is rebuild this one or get a new one. It's not my dd so I want to try to keep costs down. Anyone know of good rebuild kits