Charging Problem

[teal94_stang]

I just moved my battery to the trunk and now my alternator is not charging the battery. Both the alt. and battery tested okay at the parts store. I ran 2ga wire down to the starter and both the alt. and fuse box are tied in there as well. Do i need to have the alt. on its own direct cable? I was told all 3 need to be linked in a certian sequence. are there any grounds that could cause it not to charge? Any suggestions will help im lost

 

[64post]

Is the field wire (exciter circuit) working? does it power up with ignition on? a good ground from block to chassis won't hurt, try attaching a jumper cable from block to chassis and see if the volt meter jumps up a bit while engine is running. also if you have underdrive pulley set you may not get enough rpm to show any charge at idle as mine does, bring revs to 2k see if it makes a difference. Good luck

 

[teal94_stang]

No underdrive pulleys. yes both the white/yellow and green/red wires going into the alt. plug are charging up with the igntion is on. Tried the jumper cable ground and nothing changes.

 

[HISSIN50]

Does the charge cable have continuity throughout its length (if you have circuit protection, did it open)?

Is the battery light illuminated?

Is the stator wire plugged in and tight (it's the lone wire on the body of the alt)? Heat and NVH can loosen the connector and the circuit can open.

Is the alt powdercoated or painted?

 

[teal94_stang]

Yes the charge cable has good power all the way to the front of the car. The stator wire is plugged in but seems to be a little loose. The alt is not painted. Could it be my negative battery cable? I grounded it to one of the seatbelt clips under the back seat...should it go straight to the frame instead?

 

[revhead347]

If the ground is good enough to start the car, then that's not the problem. Did you run another ground strap from the body to the engine?

Kurt

 

[teal94_stang]

Yup i just ran another strap from the block to the frame to be sure and still nothing....

 

[HISSIN50]

At the regulator with the car idling, carefully check the wires (they're labeled A, S, I on the reg) and post what each shows.

 

[teal94_stang]

A-11.75
S-10.25
I-11.41

 

[HISSIN50]

S is a little high - IIRC it should be about 1/2 battery voltage. Is there continuity between the two stator loops?

I didn't see it noted if the alt light is illuminated while the car idles. If it is not on, does it prove-out when the key is turned on?

 

[teal94_stang]

yes there is continuity between the 2. The alt light is not aluminated at all weather the car is running or in the acc. position. The battery light appears when the juice starts to get low but is not on all the time....

 

[revhead347]

Could be the alternator light is burned out, and that's why it's not illuminating. Is there any voltage difference when the car is running vs not running?

Kurt

 

[teal94_stang]

Nope no voltage change what so ever, not even directly out of the alt post. Have you ever heard of an alt testing good but be shot? Ive owned the thing for 5 years and never out one on it so its old. Just saying that i cant see it being anything else from what ive tested...

 

[teal94_stang]

I read today about a secondary ground that goes from back of the intake to the firewall and could not find one anywhere. Could this cause the alt not to charge?

 

[HISSIN50]

Foxes have that ground - I don't remember it on 94-95's.
If you have doubts about the ground plane, one could run a jumper cable from the alt body to the negative battery post.

Bench tests have been wrong in the past. I didn't understand about the alt light (it should prove-out when the key is on, but the car is off).
I might double check the excite circuit just to be sure it is functional.

 

[teal94_stang]

I looked on the back of the cluster and could not find a bulb that was labeled for the alt. Would it be under somthing else or did i over look it? I also read too that if the bulb is burned out then that would cause it not to charge but all wires are getting power to the alt so im not sure what to do at this point.

 

[HISSIN50]

The charging-system warning-light looks like a battery IIRC.

The alt will function if the bulb burns out. But if the light does not prove-out, we need to ensure the circuit is not compromised.

 

[99FiveOh]

I'm almost positive that if you turn your key to the "on" position that battery light will stay illuminated until the car is started. Then, if the alternator is charging, it will go out.

Did this problem happen right after you put the battery in the trunk? If this is the case then your problem is something that you did during your project. You need to retrace your steps and double check all your work. A fuse could have been popped during the re-installation as well.

 

[teal94_stang]

Well i found out what the problem was, the ground off the alt itself was not connected to the frame. Its reading good volts now and no further problems. I am not sure how i over looked it but I should have seen it the first time i went through everything. I'm sorry for posting a topic over what it turned out to be but hell i learned some great alternator trouble shooting steps that i didnt know before. Thanks again for all the input guys.

 

[99FiveOh]

Glad you got it handled, but what ground off the alt are you referring to? The alternator usually grounds itself to the engine and the engine grounds to the frame.