Electrical problem

cadboy · Post by **cadboy** » Tue Mar 11, 14 10:01 pm

Help!

Changed the wiring to get rid of the AMMETER and the fire wall connection for the alternator feed and back to starter.

Followed the wiring and advice, put new cable from alternator to starter relay +, using inline fuse.
Two new cables direct through the connector (took out the connection), linked under dash to black and red cables feeding AMP, linked the black and red cables away from the AMP. These two new cables connected via another fuse to starter relay +.
From starter relay + new cable to battery +

Cable sizes used 6mm & 10mm for direct alternator to battery.

Checked all wiring for continuity and resistance, looks okay (I think).

Battery charged up 13.5V
Started the car reading at battery terminals 12.7V
Rev the engine and no change in voltage 12.7V
Engine off battery reading back up 13.2V

Alternator 2 field wires and electronic regulator new and working before car went to sleep in October.

Any advice

autofetish · Post by **autofetish** » Wed Mar 12, 14 8:17 am

Ok so alternator out put goes to starter and starter to battery yes ?

Then as you know it much the same a skinny post

Forget what you have done with dash and A meter.

Look at reg and other post is it earthed and connected like the picture I posted ? Double triple check all connections

autofetish · Post by **autofetish** » Wed Mar 12, 14 8:21 am

It early and no coffie yet so wait for someone else to confirm

But surly if you take the field wire off the alternator it should run at full wack this will test the alternator is a gooden

Just thinking out loud

autofetish · Post by **autofetish** » Wed Mar 12, 14 8:24 am

Again early but are you sending power down the exciter wire to alternator ???

Dave-R · Post by **Dave-R** » Wed Mar 12, 14 9:22 am

Off the top of my head (and my memory of this is hazey) For the alternator to work it needs one field wire on it with battery voltage and the other field wire routes to chassis ground via the regulator (I think).

The regulator then regulates the alternator output by switching to ground on and off every time the voltage reaches the correct level.

The bit I can't remember is if it is the live side or the ground side the regulator switches. But I do know it has to have a good ground to the bodywork.

The volts you have measured tells me the alternator is not outputting anything.
So it either does not have voltage to the fiield wire or a ground from it to complete the circuit.

Try hooking a wire fron the battery to the field to see if the alternator then starts outputting.

cadboy · Post by **cadboy** » Wed Mar 12, 14 8:16 pm

Have checked and checked and there is voltage on the field wires, both of them, same voltage as the battery.

have taken thefield wire out of the alternator, no changeon the output of alternator.

Have put direct cable from battery + to fieldof the alternator, still no change.

have a direct cable from battery - to the regulator body bolt and good earth checked by ohm meter.

could the alternator be dead? How can I confirm that?
What would kill the new alternator.

cadboy · Post by **cadboy** » Wed Mar 12, 14 8:20 pm

autofetish wrote:It early and no coffie yet so wait for someone else to confirm

But surly if you take the field wire off the alternator it should run at full wack this will test the alternator is a gooden

Just thinking out loud

direct cableto alternator and only battery voltage at alt output,does it mean alternator is dead

morgan · Post by **morgan** » Thu Mar 13, 14 10:36 am

I've got a day off today to do this.
I have just spent 2 very uncomfortable hours contorted under the dash with that rats nest of wiring. As usual the problem is access... I cant find the taped/welded splice anywhere. I need it to run the second wire through.

Before I tear the whole damn car apart, where did you find it [roughly] ? I really don't want to de-tape the whole damn loom to find it.

I am really very cross. (came through here to calm down). Why is every 10-minute-job so prone to become impossible ??

Dave-R · Post by **Dave-R** » Thu Mar 13, 14 10:43 am

cadboy wrote:could the alternator be dead? How can I confirm that?
.

Think you have confirmed it is dead.

One thing that might kill it. The output stud goes through the alternator case with an insulator. If the stud gets over tightened the insulator can split and short the stud to the case (which is earthed). So it might be worth disconnecting all the wires to the alt. and see if you have any continuity between the case and the stud.

cadboy · Post by **cadboy** » Thu Mar 13, 14 12:46 pm

Dave wrote:
cadboy wrote:could the alternator be dead? How can I confirm that?
.
Think you have confirmed it is dead.

One thing that might kill it. The output stud goes through the alternator case with an insulator. If the stud gets over tightened the insulator can split and short the stud to the case (which is earthed). So it might be worth disconnecting all the wires to the alt. and see if you have any continuity between the case and the stud.

Thanks Dave I will check on this tonight.

cadboy · Post by **cadboy** » Thu Mar 13, 14 12:51 pm

morgan wrote:I've got a day off today to do this.
I have just spent 2 very uncomfortable hours contorted under the dash with that rats nest of wiring. As usual the problem is access... I cant find the taped/welded splice anywhere. I need it to run the second wire through.

Before I tear the whole damn car apart, where did you find it [roughly] ? I really don't want to de-tape the whole damn loom to find it.

I am really very cross. (came through here to calm down). Why is every 10-minute-job so prone to become impossible ??

I had the dash out at the time so I got the two cables from the back of the AMMETER and joined them.

Find the two cables going through the firewall and take them out of the connector then follow this

morgan · Post by **morgan** » Thu Mar 13, 14 1:22 pm

Yeah, ta. You have answered my question ' dash out'.
After 3 fruitless hours I gave up and put the ammeter back in.

The problem as always is access. It was this 'madelectrical' diagram I was following (I have all the wire, correct fusible links, shrink wrap, the works - but I cant a) Get to the wires on the ammeter to splice properly and b) find the 'welded splice to properly connect back and bypass connectors.

Its OK. Its always an access prob. It will have to wait until I take the dash out (which frankly I didn't want to do) !

Back on the list...

cadboy · Post by **cadboy** » Mon Mar 24, 14 7:21 am

UPDATE

tested the alternator with connection to ground on one side of the filed and charges okay

Got a new regulator from Chris and the charging system is now working as it should and hopefully will be reliable.

move on to next job.