Five-8

Hi All

I am currently trying to diagnose (mostly by process of elimination), why i seem to be getting no juice from the new alternator.I am reading thru the threads here and following the troubleshooting wisdom to remedy the situation.

The Story;
Old alternator was charging (low at idle though as in under 11) but was charging at least in some capacity to something normal...voltmeter in car however started spiking intermittently with no pattern for things like bumps in the road)
Rightly or wrongly i suspected the voltage regulator, and decided to replace it and the alternator since the cost difference was minimal.

New alternator is in and seems not to be charging, I get 12.6 at both the battery and the jump post with car off...i lose about .6 with car running at both places.

I installed a fresh battery this morning, and changed the ground strap and am now going to change the belt and then pull the cover and check the output on the alternator.
And check/clean the ground points again!

My question really at this point is...can i pretty much eliminate the battery as a culprit?

All input much appreciated!

Cheers,

LT Texan

is the exciter wire getting 12V's?

Five-8

Dan, haven't got there yet, but thanks for reminding me to check this once i get the cover off.I have a replacement resistor/diode for the dash if needs be.

Cheers,

davek9

Have you checked the 14 Pin connector, that's where the exciter wire runs to.

Alan

Lack of battery charging when running is never the fauit of the battery if it is at 12.6v at rest.

Seems likely your exciter circuit is not even connected up. When you turn ignition on do you see the charge light come on? I suspect not.

for an '82 check the voltage with ignition on and car not running at pin Z1 on the central elctric panel. It should be at a few volts - if it is at battery voltage you probably have a bad connection bewteen there an the alternator - if its at 0v you have a problem in the instrument pod.

Check this again when running - it should be at close to the voltage on the jump post.

Alan

Five-8

Alan you are correct the charge/warning light does not come on with the ignition.

Changing the alt belt, and decided to change the other belts while i'm at it...so it'll be a while before i can report back.Soon as i'm have this done i'll start chasing the exciter circuit.
Thanks fellas!

Cheers,

Mrmerlin

the blue wire exciter circuit should be checked for continuity from the alternator to the 14 pin connector.

NOTE the blue wire is usually damaged about 4 inches up the sheath from its connecting point ,
this happens when the alternator is left to hang on its harness.
best to use a coat hanger and hook the alternator so the wires are not holding it .

NOTE to check the wire remove the blue wire from the alternator ,
then connect one end of the multi meter to the wire then go to the 14 pin connector find the blue wire pin and see if you have continuity.

NOTE if no continuity then the wire is broken,
roll back the orange sheathing about 4 inches from the connection point at the alternator,
and find the broken wire

Five-8

Abandoned my belt changing(struggling with the power steering pump-doesnt want to move nicely) thats a fight for later.
Pulled the cover off the alternator...i have my 12.? at the output...exciter wire with the ignition off and grounding the multimeter to the alternator casing gives me 12.? and with ignition on gives me something under 2. (sorry multimeter is just a cheapy)...both of these show as negative values(sorry don't know what that means).

Should i now do what Stan suggests and check for continuity on the exciter wire?

I appreciate you guys helping out, this is all a big learning curve for me

Cheers,

Adrian

Mrmerlin

I think you should go buy a good mutli meter,
it wouldnt be the first time weird readings have been obtained from inexpensive tools.

Five-8

I have been known to "confuse" things...pretty sure the wiring here is correct. Can someone just confirm?

Stan...going tomorow to get a decent multimeter.

Cheers,

Mrmerlin

that looks like a Paris Rhone alternator,
you need to remove the small wire,
and check for continuity to the 14 pin connector

Five-8

Will do Stan...might need longer arms :-)

ROG100

Adrian is that not the new Bosch alternator I supplied? I am not so sure the black box should be used on the new alternator but Alan or Stan will put us right.

Alan

OK a few problems here...

When installed the case is grounded by the bolts to the block - right now it isn't grounded at all - no good for measurement. Thats why you see negative measurements - your ground is actually at battery voltage - if you measure to the main terminal you will see ~0v - proof.

Connect the case to the chassis ground and remeasure - but also connect your multlimeter ground to this same chassis ground (you can use one wire of a booster cable for this).

Then remeasure.

Alan

Five-8

Yes Roger...it is....i asked you in an email about the black box, cuz i was unsure of what it was, was anxious to get it in...so i went ahead without you :-)

Cheers,