large common 70s style alternator,

how can you know if an alternator is putting out anything?

i need to test for this on the alt thats on the 350 engine in the trans am,

i accidently grounded the batt post on back of the alt for a second, made a little spark, not very much at all, not really even a zap,

will a screwdriver etc stick to the end cap of the shaft if its been zapped, or will it stick to it anyways no matter what when its rotating from the engine belt?

i have a small nothing special cheap digital multi tester, what can i do with it to test for just output to know if the alt died today ?

thanks

 

using a cheap mulitmeter (or anything that can read volts for that matter) all you should have to do is start your car and put the leads on your battery, it should read about 13 volts; anything less and I bet you fried it. I suppose that the easiest way is just to run your car, if it dies then you know your alt is junk, either way works.

 

Crank the car and then unhook the battery. If the car dies, the alternator is no good. *












* This is NOT going to make the ECM happy, so if you happen to fry your computer doing it this way it's not my fault. The odds are fairly slim but still......

A multimeter is much more efficient.

 

cool deal very appreciated, i hear rumors that running no battery connected is a bad thing to do, but ive never seen anything bad happen from it unless something was already bad in the first place,

right ?

thanks

gonna do that test in the AM, that ought to wake up any late sleepers, remember the T/A has no exhaust at all but damn it sounds good

 

that little spark you get when you unhook the battery with the motor running is called an inductive spike, it's 2500+ volts, the bigger the spark,... the bigger the spike... everything that is turned on when it happens will see that spike.

like TheGreatJ said " * This is NOT going to make the ECM happy, so if you happen to fry your computer doing it this way it's not my fault."

best to use the voltmeter.

 

no, this was before i even fired up this engine in this car for the very first time, my wrench hit metal for a split second when i was loosening up the nut today earlier so i could move the wires so i could put the valve cover on the pass side

after that i unhooked the battery

and this car has no ECM or even the harness for it, its all gone, removed years ago completely from engine to ECM



thanks

 

a magnetic field is generated at the rear bearing when an alternator is charging, using a screwdriver touch the bearing surface and see if the tool will stick to it

 

Make sure when you test the voltage of the alternator you have as many accessorys on as possible. That will simulate a high load situation for the alternator.

 

well screwdrive ris very attracted to center of alternator with car running, and i disconnect cable with it running and it stays running, put it back on and cable arcs at the battery post, but it doesnt drag the engine speed down any at all, and i know the battery is down some ive been using it to crank and crank the car and run accessories while i reconnect wiring, so shouldnt it drag the engine speed down a little when you reconnect the cable to the battery post ?

if not then why not ?

ive got right about 13 volts showing on my amp guage with key just on and engine off,

were 82 equipped with ammeter or voltmeter ?

looks like voltmeter,

i think thats a stupid question and i answered myself already, but im asking anyways to make sure,.



thanks

 

Sounds like you have a working alternator

 

i think so :P

thanks