Charging System Not Working

[E30Eric]

For the record I’ll state that I have not had any other significant electrical problems in the time I’ve owned the car. (9 months)
The car just died again on the way to work this morning. Started with the V1 quitting, then I noticed the stereo would not turn on. I immediately turned off the lights to attempt to save what little power the battery had left. I replaced the alternator yesterday. I replaced the battery a few days before that due to the same thing happening last week. Also I have yet to see the battery warning light come on once. The light is not burned out either. When I was driving around yesterday the car seemed to be fixed after I put in the new alternator. I had my old alternator tested and it failed, so when I replaced it I thought it had been the problem. With the new alternator in I was getting 13.6v at idle, before I was getting 11.52v. The B+ lead for the alternator is getting voltage through it. I checked continuity through the D+ and I did have continuity with ground. I don’t know if that is bad or not. I didn’t get any continuity to ground through the B+ lead with the battery disconnected.

Car is a 1988 SuperETA
With all the “I” goodies J

HELP HELP!

Thanks,
-Eric

[DaveSmed]

With the key on, D+ should be 12v+ if checking with a digital multimeter

[E30Eric]

New developments! I tried to leave work yesterday, the car started and made it about a mile before I had to make an unscheduled stop and roll it into the Future of flight museum parking lot at work…

Symptoms:
Everything dimmed down till the car just shut down.
Would not turn over.
Battery was in the 11.XXv range.

I started testing the leads from the battery forward.
-The big 2g wire from the battery to the distribution block didn’t have any shorts.
-The wire from the distribution block to the starter didn’t have any shorts.
-The wire from the starter lead to the alternator didn’t have any shorts.
-The alternator had good continuity with ground.

Those were all testes via continuity test. Today I’m going to pull the fuses one by one and do an inline volt test.

I was able to limp the car home last night with a different battery.

-My neighbor mentioned that if I had drained the new battery I bought before I had bought and installed the new alternator a few days later that the battery might not have enough amps to rectify the excited diodes to start charging the system. Does that make any sense?
I put the battery on the trickle charger and am going to mess with it more today after work.

Any input?

Thanks!
-Eric

[jlevie]

Since you've replaced the battery and the alternator, the logical tests at this point would be to check the voltage at the battery while the engine is running. At idle you should see something better than 13.6v, rising to 14v or better at 2500rpm. If you see less than that, see what the voltage is at the alternator. If the voltage is normal at the alternator, but low at the battery there's a problem with the power or ground connections. If low at both test points the alternator is bad.

[E30Eric]

Ok I'm testing shit as we speak.

So far:

(Car On)
12.57v @ Bat.
12.58v @ Alt B+ all wires connected as normal.
12.00v @ Alt D+ all wires connected as normal.

(Car Off)
13.24v @ Bat.

[Danny]

This might be too simple to work.

But check your connections something could be wiggling?

[E30Eric]

.011A to .012A if i place the multi meter between the + lead and + battery post. Does that say anything?

[E30Eric]

Could the new alternator be a bad one? I charged the battery all night at 10A and it has a solid charge.

[DaveSmed]

Ok I'm testing shit as we speak.

So far:

(Car On)
12.57v @ Bat.
12.58v @ Alt B+ all wires connected as normal.
12.00v @ Alt D+ all wires connected as normal.

(Car Off)
13.24v @ Bat.

Wait. Car on as in running? or Key on?

[n2motorsports]

This might be too simple to work.

But check your connections something could be wiggling?

yes, make sure your batt connections are tight...one time i purchased a slightly larger connection than the batt terminal and while driving to work, same thing...lights begin to dim then i loss all power...it happened on the 5s to 520 tunnel (right at the bend), never been so scared to die in my life!

anyhow, AAA towed me to a local shop and the guy told my b/c the ground wasn't on tight, it couldn't regulate the power sent to my alt and killed the alt. so check your connections and bring your alt to schucks for them to test it.

[E30Eric]

Took the alternator to shmucks. FAIL. It's rebuilt one from them. Broken from the get go. Better yet, when I removed it from the car a big chunk of solder fell out of the alternator case.. go figure. Getting a new one tomorrow. Wish me luck. I'm sick of driving around my loud ass integra.

[E30Eric]

Replaced the alternator today with one rebuilt in USA rather than Mexico... Needless to say it works now. I got 14.32v at idle with the car on with my lumpy ass cam.