1G Alternator not charging.

[4gfun]

For my Laser...

I have 2 good batteries and 2 alternators, one of which I know is working.

The Alternator does NOTHING to charge the car.

If you disconnect it while it is running, the car dies immediately. Yes, I know you aren't supposed to do that and I won't make a habit of it nor did I do that with the 2nd alternator.

I have swapped out the alternator relay and the 80 amp fusible link is good.

The B terminal of the alternator is at Battery Voltage as well.

Previous owner mentioned he left some ground off the tranny when installing it, but I don't see any missing grounds at all.

I even grounded the alternator to the battery with a set of jumper cables as a test.

I have swapped the ECU as well. VOM shows the tale of a fully charged battery slowly dropping from 12.5 VDC down to 9 volts until the car dies.

What could possibly be causing this situation?

I need more advanced tips to get me through this.

Thanks!

 

[4gfun]

With the car running, I am getting 12.25 VDC on alternator S Terminal and 5.6 VDC on the L Terminal. This is with the connector in place and jumping into the wires.

With the connector disconnected, I am getting 12.25 VDC on the alternator S Terminal and 11.09 VDC on the alternator L Terminal.

Why 5.6 VDC when it is connected? Can I run 12 VDC to the L terminal with the car running?

What exactly is behind the L terminal?

 

[4gfun]

It looks like I only have to concern myself with this part of the circuit...see attached.

What is the area in the red square??

Is that the battery light and the alternator relay??

Could a bad ignition switch be causing this mess? If I turn the key 100 times, I can get the key to turn.

 

[tmoney20g]

That's a lamp + diode on the top, and resistor + diode on the bottom. Researching the charging circuit.

BTW, there is a fat ground wire that goes from the transmission mounting bolt at the top of the block, next to the starter, up to the battery ground. Then from the battery ground, that same size also goes to the firewall. You definitely need these grounds, and some circuits ground thru the motor, thru that wire, etc...

 

[tmoney20g]

Looks like you were right:

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[tmoney20g]

And if this helps any:

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[4gfun]

Thanks for all that.

So I ran 12VDC directly to the L terminal and still won't freaking charge!

I am also noticing the coolant and battery lights flashing every few seconds at the same pace. It doesn't always do that, but when it does, it's like it's trying to give me some message.

I think that these grounds are already in place already. I'll have to check again.

 

[1990dsmkid]

Have you actually removed and looked at the 80amp fuse? Mine blew but looked fine when just looking at it while it was still in fuse box. Fought with a charging issue until I finally pulled it and found it to be blew

 

[4gfun]

Have you actually removed and looked at the 80amp fuse? Mine blew but looked fine when just looking at it while it was still in fuse box. Fought with a charging issue until I finally pulled it and found it to be blew

I did, as a matter of fact I took it out and used a continuity tester on it and every single fuse or fuseable link in the car. I found 2 blown fuses, one for the cigarette lighter and one for the doors, but they were both in the internal fuse box.

 

[yhype]

If you truly have all your powers and grounds, the only other thing left is the belt possibly slipping for some reason.

 

[4gfun]

If you truly have all your powers and grounds, the only other thing left is the belt possibly slipping for some reason.

Well I did put it on like a lazy bastard, the alternator is just kind of laying there in place on i'ts rear mount, I don't even have the rear bolt installed much less the front tensioning bolts installed.

I figured that some slipeage is allowed and as long as the pulley is turning it could squawk away all it wanted. You can clearly see the guts inside the alternator turning.

Wrong?

 

[4gfun]

*Important* As far as grounding goes, if I simply take a huge gauge battery cable and run it between the negative battery terminal and the alternator body, shouldn't this at least temporarily bypass the need to check all of my grounds? Just as a quick test? Shouldn't that be sufficient??

 

[97eclipsealovelost]

A heavy gauge wire should work as a ground but you might want to check your existing ground wires could be a bad wire or were they are grounding could possibly be coroded or just not making a good connection but definitely get the bolts in to your alt and under tension.

 

[4gfun]

I went and tensioned the alternator up. I also found the 2nd ground that should have gone from the transmission to the passenger side A/C bracket broken.

I replaced it and have a charge. So it was one of the three things:

1) Bad Alternator
2) Missing Ground
3) Too lazy to mount the alternator correctly.

I don't really care which it was. I am going to leave it alone now!!

Thanks for sticking in there with me everyone!

 

[donniekak]

Try unplugging the 2 wire plug from the alternator, and only run the b terminal connection. Then start the car and rev it to about 4000 Rpms and see if it charges. If the alternator is good, it will self excite and charge.

 

[4gfun]

Try unplugging the 2 wire plug from the alternator, and only run the b terminal connection. Then start the car and rev it to about 4000 Rpms and see if it charges. If the alternator is good, it will self excite and charge.

Thanks, but it is fixed. I think you missed my last post.

 

[donniekak]

Thanks, but it is fixed. I think you missed my last post.

I was on my phone and didn't see all the posts.

 

[4gfun]

I was on my phone and didn't see all the posts.

Yep, just so happy it is fixed. Thanks for the extra tips.