Alternator woes!

[Chavtastic]

Hi guys,

Which parts of the wiring loom would cause bad alternator output? Is it just the +ive and -ive feeds from it? Or would say the battery to chassis earth wire cause bad performance as well?

Basically my voltmeter reads anything from 10v to 13.5v (randomly) and the battery needs a charger on it every week.

Could the regulator need changing or something???

Cheers

[Stupink]

The small wire is a priming wire, this is the one that goes to the Dash light, this should supply 12v to the alternator from the battery initially as you're starting the car, this "switches" the alternator on and starts it charging, it then should have no flow as it should match the voltage of the battery, unless of course your alternator fails, then the flow will be into the alternator and thus the ligth glows [img]/smile.gif[/img]

So you need that one to start it working, and then obviously the main output and chassis earth create the circuit for the actual charging.

is it 13v then 10v on load? or isnt the voltage to do with battery useage? it sounds like either the belt is slipping, or the alternator(yeah regulator pack usually) needs replacing. but its worth checking the earthing etc etc first and also the actual voltage over the battery with a multimeter if you have one.

11-12v standing, raising to 13-14v idle, dropping to no less than your origional standing voltage with "average" load imposed on it(lights radio internal fan etc) and a few rpm just to imitate driving revs.

[Chavtastic]

Cheers Stu!

Well the voltage at best is 13 or 13.5 when no ICE is on... so surely the alternator can't be completely knackered?

Then with the ICE on it can go down to 10 volts or less, even throwing the ECU light on at times! Then if I switch the ICE off and all the electrics it will sometimes go back up to 12 volts or sometimes stay low and the car keeps cutting out.

God knows...

I might just bring it down to Big Stu's Car Clinic

[Stupink]

well leaving your ice off, do you ever have any problems?

The older turbos with the Vbelt not the 3/4 belt only had a 70amp alternator.. I dont know what you have but you might just be overloading it.. try putting on the other electrics, wipers lights fan etc without your ice and see how much it takes before it drops below the initial standing voltage. I think on mine i pretty much had to have it all on full at once, It was mainly flicking the heated seats on ontop of everything else that did it..

[Chavtastic]

It all seemed okay until I started doing my DIY wiring in the engine bay

I had these crappy rusty terminals on my battery so I changed them for some nice shineee brass ones. The thing is; I connected them all back properly and securely but it doesn't seem right since.

Oh gawd I've just realised this is the problem

No going back now... what should I do?

Stu you're a legend

[Stupink]

If you think what you've done has created the problem time to go over it all and double check everything... actually didnt you relocate the battery to the boot? are you sure you got a decent earthing point? or did you run it up to the front?..
if its as intermittent and random as you say, sounds like a loose connection.. remove all.. examine... put back.. prey [img]/tongue.gif[/img]

[Chavtastic]

Okay mate I'm gonna re-wire it all on Friday and see how it goes! I'll solder on some extra wires and clean up all the earth points I can find!

Cheers mate - beer in the post [img]/smile.gif[/img]