Dead Alternator?

[Grim.Badger 15]

After visiting a friend in Bradford I topped up with new oil. After this the car was initially sluggish and I got a couple of judders which seemed to be from the clutch (new clutch and oil seal so I'm not worried about that). Eventually the car freed up but at the same time the battery warning light came on. After about and hour and a half of driving and lights getting dimmer the car finally started to missfire as the pump lost power and I had to stop.

The AA man was fairly confident it's the alternator. The brown multiplug is fairly clean, although I do have problems with my starter motor which are corrected by a bypass wire, and the earth on the battery appear good and was taken off (and presumably cleaned) a couple of months ago when I had the new clutch put in.

Is it likely to be the alternator itself, or the wires from it?

 

Cheers

[Faz85 0]

have you tried connecting a voltmeter up to the alternator? connect the +ve up to the contact and earth it to the battery, with the engine running, and you should be getting more than 12V (about 15 IIRC)

 

if your getting less than that, i would say a replacement is in order...but if you get no voltage reading or an inconsistent reading, i would check the wiring.

 

Faraz

[Grim.Badger 15]

The AA bloke put one on when he jump started it. It started over 12v then rapidly dropped (but seemed consistent) Managed to get home on the AA battery though.

Edited December 6, 2006 by Grim.Badger

[ade 4wd 11]

Does the battery light on the dash come on when you switch on the ignition, and go out when the engine is running? If not check the brown multiplug on the engine loom as the warning light on the dash is connected through that. If you cant get the warning light to come on it is most likely the brushes have worn in the alternator.

[Grim.Badger 15]

Eventually the car freed up but at the same time the battery warning light came on.

 

I don't know if it will come on again as I can't start the car until I'm sure it can recharge the battery. The battery light was dim when the engine was running, but wouldn't go off. It also flickered if you reved the engine in neutral with all the ancilleries off.

[pug_ham 242 3 Cars]

Sounds like the classic symptoms of a dead alternator.

 

Time for a replacement. Try to get a decebnt diesel one if you go for a s/h one though.

 

Graham.

[Grim.Badger 15]

I'll probably get new, but out of interest, why a diesel one if I get second hand? GSF claim the diesel and GTi ones are the same

[pug_ham 242 3 Cars]

Diesels & TD's are different on some years, either 50 or 70 amp output for both diesel or GTi so they could be the same.

 

Just look at the selection for the XU engine on the parts cd.

 

Graham.

[Ahl 4]

Don't you mean the diesel starter motors have a higher output Graham?

 

The diesel engine will need less alternator power than a petrol engine due to the lack of spark plugs and other electric bits.

[pug_ham 242 3 Cars]

Don't you mean the diesel starter motors have a higher output Graham?

No.

 

The battery is also a higher amp rating afaik, there a choice of three different alternator ratings, 50, 70 & 80 amp which would match the different battery outputs imo.

 

I've just been looking for a late header tank for Hilgie & found I've got an 80 amp alternator I didn't realise I had. d)

 

Graham.

[Grim.Badger 15]

Right I've fitted a remanufactured alternator and the belt is on and properly tensioned. The battery light stayed on and the car stopped 5 minutes later. Then I changed the connection on the thick live wire, and changed the entire negative wire up to 3 inches after the brown multiplug, so it doesn't go through the multiplug anymore; still the battery light stays on.

I've connected the thick live wire to the slightly thicker electrode on the alternator marked with a +, the thinner wire is connected to the thinner electrode marked with a -.

 

Why isn't it working? Have I got the wires the wrong way around? Help me before I set the damn thing on fire

[Anthony 1,000]

If the light is on then it's nothing to do with the multiplug.

 

The main power feed should be connected to the screw terminal marked "+" and the thin warning lamp wire should normally connect to the spade connector. You'll usually have one screw terminal and sometimes one spade connector unused.

[pug_ham 242 3 Cars]

It sounds like you've wired it up wrong.

 

There should be only one thinner wire with a spade connector on the alternator & that does run through the brown multiplug. If there are two male spade terminals on the alternator, I don't think it matters which you use.

 

On the alternator I have down stairs it also has a -ve terminal but I've never seen one used, the alternator earths thorugh the engine block.

 

The thick wire connected to the +ve electrode (ring terminal) comes from the battery via the starter.

 

Graham.

[Grim.Badger 15]

Cheers, I'd managed to miss the spade connector and was trying to use the two ring connections