champster

I recently got an 87 Camaro 2.8.

My Voltage gauge was low, so, based on the hum, I changed out the alternator. (Gotta love cars where you on change a car part, on lunch, in dress clothes ;-) )

Problem went away for a while, then came back.

I changed the battery.

Problem went away for a while, then came back.

It seems like I have a drain on the system somewhere.
My AC/Heat blower, radio, turn signals, all drop the voltage needle more.
Even my Tach wiggles with the turn signals, etc.

Any idea where to look next?

champster

OK, Maybe not drain.
Maybe it is just not charging.

I found a thread to follow and meter some points.

Since I changed the Battery and Alternator, I know those wires seemed fine.
I didn't realize that it went through the starter first. I'll check those terminals and wires.

champster

I get 12.1 volts at the battery.
If I start the car, I get 9.5 volts. (didn't check all that was turned on)

I assume the alternator is doing nothing.

I disconnected the + terminal and I get 0.3 Volts between terminal and alternator housing.

As for the other 3 wires.
Big red is same as battery. No (on my meter) resistance from Battery +
White (second wire) is battery voltage when IGN is on.
Brown wire does nothing. Not sure where it goes.
I don't see a Battery dummy light on any of the bottom dash lights, nor a light on the gauge.

Is my problem an alternator (which is new, and I wonder if I even had to change it or if I had this same problem the whole time) ?

Is my problem the trigger wire? I still don't know if the white or brown is trigger.

champster

I'll have to doublecheck, but I think this is the replacement I put in.
http://econtent.autozone.com:24999/z...2/0/86/523.pdf

It says I can use I or L. I'll doublecheck, but "I" had battery power.

Berlinetta00

Good way to test the alternator for proper operation is a full field test- on these internally regulated alternators, there are normally three terminals- the main battery positive, ignition positive, and the field terminal. They are labeled B, I, and F. Turn the vehicle on, with a multimeter set to read volts at the B terminal of the alternator and a good ground. Take a voltage reading prior to starting the test. Turn the headlights on and a/c if equipped, and use a jumper wire to contact the B terminal to the F terminal on the alternator and read voltage output. Do not keep the jumper wire in place any longer than required to take the reading, this could damage your charging and wiring system. You should recieve a voltage reading of between 15 and 17v. If the alternator passes the full field test, the problem lies elsewhere, I have seen bad ammeter and battery warning lights that have caused this problem.

champster

What else would have to left connected during the test? (Ex. Does B still need to go to battery AND Alt when I jumper it, or just battery?)

My Alt. has 5 connectors.
BAT on back and a connector with 3 wires in it. There is 4 terminals on the Alt side of that connector. S I L P
I think S is what you mean by B? It connect back to battery.
BAT connects to Battery also, via Starter.
"I" is for direct IGN power (internally registered)
L is for a battery light, which I don't have.

I do have a voltage gauge, which I just fixed a few weeks ago. I wonder if that was connected to "L" and is not working any more. When starting, the needle would peg out the meter. Problem was, no peg, so it would get stuck behind the bezel. I just put a small strip of black duct tape between the face and the bezel to keep it from getting stuck. The gauge works fine now.

With the limited testing so far, I know it is not a drain and is definately the Alternator putting our nothing.

champster

Holidays and rain.
I haven't made it back under the hood yet.