Outer Limits 4x4 Board

I was heading home from the North Coast NSW on the freeway yesterday.I noticed those three warning lamps on.Ipulled over and drained the fuel filter.There was no water in it.I tested the sub tank.It still worked.My turbo timer has reading coming from the alternator.It was down to 12.7 volts at idle and up to about 13.6volts while cruising at freeway speeds.If I put the hammer down it would sometimes get to 14volts and the three warning lights would go out momentarily till it dropped back down to the 13's.

I noticed as soon as I stopped at the lights I heard redarc clunk.So the main battery is obviously not getting its proper charge.
Is my alternator screwed?Or just the regulator.How can I test the regulator?Are those three warning lights wired together.

Anyone had anything like this? Advice appreciated.Oh yeah vehicle is a Gu 4.2 Turbo.

Cheers.

I had a similar thing happen to my motor. (5.0 v8)

But one of the brushes was stuck and I was getting no where near the same amount of charge but much higher up in the revs all the warning lights would go out because I was getting adequate charge..

I have now checked the voltage with my multimeter.The main Battery has 12.6 volts.The Aux battery has 12.6.The alternator is putting out 12.3 at idle.
More when revving.

well on the mq and mk if the brushes in the alt are gone or on there way out, The fuel filter light and the alt light comes on so i would say that yours is the same but with an extra light wired to it.

Might be a nissan thing ?

If it was the brushes can I rebulid it or am I up for a newby.

Took it to auto electrician today.Alternator is on the way out.Bill $450.Faaark. The old Kingswood was $70 for a new one!

Buckshot wrote:Took it to auto electrician today.Alternator is on the way out.Bill $450.Faaark. The old Kingswood was $70 for a new one!

must have got a cheap aftermarket one like i did not too long ago..
i did get some quotes of over $1000

Buckshot wrote:Took it to auto electrician today.Alternator is on the way out.Bill $450.Faaark. The old Kingswood was $70 for a new one!

How many amp will the new one put out though??

Buckshot wrote:Took it to auto electrician today.Alternator is on the way out.Bill $450.Faaark. The old Kingswood was $70 for a new one!

Was gonna say, your up for a new alternator. I had the exact same lights & same symptoms 2 weeks ago.

Mowie, I think the GU uses a 90amp unit. Should read 14+ volts at idle... Mine was at around 11-12. $440 later (new alt) I was good to go.

100A for GU and 90A for GQ

i did find a 120A one when i was looking but i couldnt afford it at the time

100A should be enough for me for now

Hi Guys, I know this thread is a yr old but its the only one with the exact problem I had today.

I had a different noise from the usual diesel rattle yesterday and this morning. Hard to describe.

Then after driving for an hr today the noise had gone and I had these same 3 warning lights come on. I checked the fuel filter and there didnt seem to be any water.

Was the alternater definately the problem?

Just seems strange that the Water in fuel light comes on and the subtank light. THe battery light seems logical.

Even tho I have an after market fuel filter and I think the water sensor is no longer connected

Typical this had to happen as I leave to go away for 4 days.

Thanks for any advice.

Eric

PS. 2000 GU 4.2

Just discovered the same problem on my GU3 (3 litre t/d).

Metered the battery and 12.6v with the engine off and then it drops to 11.6v when turned on.

The alternator has 12v on the input connection, but the output 12v does not change with the revs.

All the earths are good.

Am I up for a new alternator, or is there somewhere else I should be looking.

Mine was a broken alt belt. That should have been the first thing I checked

If you're geting noise from the alternator, check the obvious to start... belt and bearings. Have a look at the rear bearing - I've had a similar problem recently, rear bearing collapsed.

Failing that, pull the alternator out and check the brushes.

What ever the problem, don't be afraid to pull the alternator apart and fix it yourself. A set of bearings will be only a few bucks. Brushes are less than ten bucks. The hardest part to stripping it (when they have internal regulators or rectifier bridges) is de-soldering the stator leads and not wrecking the tabs... it'll make sense when you give it a crack. The internet has heaps of info including parts breakdown and overhaul procedures on just about everything!

If you do just buy a new one, keep the old one and pull it apart, then chuck it in the bin - you'll at least learn a little more about your car.

If it doesn't work, force it. If it breaks, it needed replacing anyway!!

Could be a stuffed diode in the rectifier, you wouldn't be able to check without stripping the alternator though and removing ther rectifier from the coil. My 89 GQ did the exact same thing, turned out i'd completely burned out the diodes in the rectifier and also stuffed the regulator. Is it perchance an after market high output alt?

Yeah, my alternator is shot. Diodes cooked and coils are a mess.

But the AE has told me he can fit a new 'clutchless' alternator for less then $400.

Does this sound right and what is the difference/issues with having a clutchless alternator.

whats a clutchles alternator

that was my question, but i guess he knows what he is talking about.