Alternator Issues

[85AW20v]

Used another voltmeter from one of the sparkies at work and there was a slight difference in readings - mine was 0.15v lower than his.

Checked and resoldered all the joints and cleaned up the plug joint in the boot as well just in case something in there was causing high resistance. No difference.

Have now cut the sensor wire in the loom and connected it straight to the +ive of the battery and charge voltage is 14.4v.

I think I'll leave it at that for now and see what happens at the next race meeting on 18 August.

Thanks people for all your help - especially Matt. I'll report back....

[85AW20v]

Had a raceday Sunday week ago and all is good. After 15 minutes of practice, alternator was charging at 14.2V so the direct wiring seems to have sorted the problem. No more battery acid through the boot now either.

Just have to sort an oil leak now which looks like it's coming from around the dipstick. Definitley not the front seal as I've taken the pulley off and its still dry behind it....

[Nuty|Mike]

Hey Simon

Im having similar problems to this .

I Have done everything , first it was a second hand alt,worked fine for a day then overcharging
then I rebuilt with bearings brushes and spare good reg and rectifier. Worked for a day then Overcharging.
Then new reg and rectifier ...... yeap after a day Overcharging .

Tried what was done in this post and it worked !! .....for a day then .......Overcharging.

Any ideas.

[85AW20v]

I cleaned up all my earths as well during my process of elimination so maybe try that. As you can tell from the questions I was asking, I'm no autosparky!!

[Nuty|Mike]

Yea fair enough ,Ill try the earths as well .

just struggling throwing new alternators at a car that keeps blowing them... the last one even did a smoke show!!

[Nuty|Mike]

so I added a Massive earth cable left over from a job at work....it charged perfect!!!

Of course though a few days later go to drive it and it overcharges straight away unlike yours it doesnt stop at 15.2v it keeps creeping with revs .

Anyone out there with ideas? next step is to remake the wiring loom and earth the shite out of the engine.

Its a nice 1980's dust catcher at the moment.

[GDII]

What is the car you have? Any wiring been messed with for the charging circuit?

[Nuty|Mike]

Hey

Same as simon AW11 20v silvertop and nah the wiring all original from alternator to fusebox/battery.

Oh and problem started after Jump starting one day...... all fuses ok.

[GDII]

Do all AW11s have the external regulator or is this only some of them? I assume yours had the internal regulator is you say the wiring is all standard but you are running a 20V.

The BGB says if the voltage is above 15.1v at 25 degrees C then replace the IC Regulator.
But as you have already replaced the whole alternator with good ones it's not that.

Have you tried a new battery?

How well is the alternator earthed to the bracket and engine? Just an idea but I don't think it is this as you said it happened after a jump start. I have heard of someone painting/powdercoating the bracket so the earth circuit was no longer working. But that doesn't make sense as you wouldn't get a voltage at all.

Were the jumper leads put around the wrong way at first? I guess you would know as it may have damaged more than just the alternator system.

[Nuty|Mike]

Hey , yea internally reg'd Alternator and have tried mulitple regs new and s/h .

Currently have large earth directly to the altternator bolt to a sanded part of body this worked for a little bit then its gone back to its overcharging ways.

When I connect the alt to the battery it is sucking voltage with nothing on .... thinking internal short in alternator ? But why with same issue and two alts.

[Nuty|Mike]

oh and pretty much brand new battery .Also swapped battery with the one from my daily and still issues.

[GDII]

Maybe there is a short in the system. Go grab a wiring diagram and check that the wires aren't earthed where they shouldn't be.

One wire is hooked up to multiple other circuits.

[XS1V]

Post from the past come back to get you

Brad