Alt not charging

[Markus56]

85 GL wagon, maxima alt swap

 

When the car is running, i can only get 11 or so volts out of the alternator.

 

i had the alt tested two different times at different parts stores using different types of machines, and the alt has tested good in all areas.

 

It worked for the first time i had it installed, then when i was backing out of a parking lot, something happened and all the electrical shut off. i played with the black fusible link and everything turned back on, except the alt stopped charging. took the alt out and had it tested, it is fine. threw it back in, nothing. replaced the black fusible link, and still nothing.

 

what are some things that could be going on?

 

BTW, should the black wire in the alt plug have 12v when the ignition is off?

And should they both have 12v when the ignition is on?

[crazyman03]

hows your battery? if its toast it wont hold a charge.

 

 

-Justin

[edrach]

I don't care what they tell you the alternator or a faulty wire is the issue. Even if the battery won't hold a charge, the alternator should still put out 13 to 14 volts at about 2000 rpm.

[Cougar]

It would be good to know if the battery warning light turns on when you turn the key to the RUN position. It is important that the light functions in that mode because it supplies power to the alternator field windings. If power doesn't get to the windings then the alternator can't produce any power. The warning light is basically grounded through the field windings in that mode so there will be a low voltage at that back side connection point until the alternator field builds up while running. Then you will have some backfeed from the alternator which turns the warning light off and shows the alternator is working. The other wire is a battery sense wire and should be close to the battery voltage.

[Markus56]

No dash lights turn on when the key is set to the run position

[Cougar]

If none of the warning lights in the dash are turning on then you have a power problem. Check the fusible links in the plastic box mounted on the coolant reservoir. Also check the fuses under the hood.

[Markus56]

That's the first thing i did, but i will double check.

[Cougar]

Hopefully you are using something like a test light probe to prove that power is getting to where it needs to be. The trouble may be with the ignition switch wiring.

[one eye]

This is Markus56. I was using a multimeter

Edited May 25, 2010 by one eye

[Cougar]

That will work as well of course. Since the engine can be started then maybe the trouble is with the wiring to the dash.

Edited May 25, 2010 by Cougar

[Markus56]

I dont think so. The dash gauge is reading the same as my multimeter, which is about 10.5-11.6 volts

[Cougar]

The power to the voltmeter may be on a different circuit than the one to the warning lights.

[Twitch de la Brat]

Have you checked to make sure both of the signal wires are connected and

have continuity?

 

I've had that issue when the wires come loose (GM alt swap), or I forget to plug them in

 

As for the dash lights not lighting up, I would check the back of the instrument cluster for any loose/corroded wires.

 

Also, have you completely gone through your fuseboxes?

Have you checked all the relays, fuses, fusible links, all that stuff?

 

Twitch

[Markus56]

The dash meter was working accurately without the signal wires

[Twitch de la Brat]

The dash meter was working accurately without the signal wires

 

True, but the alt needs the signal wires to know when to charge.

I found this out on my BRAT.

I'm sure its the same on an EA82 as they share alternators.

 

I believe the volt meter just reads off a circuit.

 

Twitch

[Markus56]

I had both signal wires in both spots and nothing changed

[Twitch de la Brat]

Ok.

Have you tried tracing the charging wire or getting a wiring diagram and seeing

where exactly it runs to?

If you can somehow look at the entire running of the main charging wire, you may find some broken wires, or maybe a short.

 

Another thing, have you checked the voltage straight off the alt, grounding to the body?

 

Twitch

[Cougar]

It is critical that power tied to the battery warning light gets to the alternator field wire so the alternator can build a charging field.

 

Power to the warning lights comes from the ignition switch and possibly through fuse 12. The wire coming from the warning lights to the alternator should be wht/red. To see if the alternator has a fault remove the connector on the back of the alternator and ground the w/r wire. Then turn the ignition switch to ON and see if the lights turn on. If they still don't turn on then there is a break in the w/r wire or power isn't getting to the warning lights. If the lights do turn on then replace the alternator.

[Markus56]

Well, according to MitchellonDemand, i need to pay attention to the red and black fusable links and fuses 9 and 12.

 

should have looked at the wiring diagram sooner

[Scott in Bellingham]

when are we going to go wheelin at walker??

[Cougar]

Well, according to MitchellonDemand, i need to pay attention to the red and black fusable links and fuses 9 and 12.

 

should have looked at the wiring diagram sooner

 

I take it you found a bad fuse.

[Markus56]

not yet... car is at home. I'm not

[Markus56]

when are we going to go wheelin at walker??

 

Dont get your hopes up. My lift kit still isnt finished and i need to make a skid plate

[Markus56]

OK.

 

so when i start the car, there is no charge from the alternator.

 

when i rev the car past 4k, all of a sudden the alt works, and puts out 13.4 volts or so, but then the black fusible link starts to smoke.

 

so i am going to replace the black fusible link and see what happens

 

There were no bad fuses or links

[Yo'J]

Do you have the correct pulley on the alt? I'm just following your progress.... Do you have any corrosion on or around your fusible links and are your grounds not good or are they GREAT? I'm a sucker for die-electric grease.