Alternator driving me crazy!

[mrlex]

Battery is reading 12.04 at the moment...Ill check again tomorrow!

[Jarred]

is that with the battery leads connected or disconnected?

[mrlex]

Connected...

[mrlex]

Ive also put this thread on mk1golf.org.uk and ive been told that because my dash is dead and only the speedo works this can cause my alternator not to charge? can it?

[Jarred]

well, is your dash dead? or does it still work?

if the battery is still connected and there is a short with you electrics, that could give you a false reading about the battery's health. if that makes sense.

[h100vw]

I had a duff battery in my Ibiza. Still in the shed actually, About once a week the clock would reset, it always turned over a bit slow but as it started with the second flick of the key I never bothered. One day I thought I'd get a new one, it turns over like a jet engine now.

There is a world of difference between the terminals on the battery and the connectors themselves. Doing a visual isn't enough. Everything has to be clean and the MK1 charging system isn't the best in the world to start with.

To make sure it's all in tip top condition, you should clean all the connections. Starting at the alternator stud, starter stud. I have run additional earths from the battery direct to the alternator too. Anywhere you can reduce resistance you will improve performance.

You can't measure the battery voltage just after you turned the engine off or took it off charge. You need to wait a while or load it up.
Also when checking the output, you should turn on the lights and fan to see if the alternator can still maintain it's output.

If you have problems in the clocks and they are connected still, you could have a slow drain going on which flattens the battery when not in use?
Disconnect them and see if things change.

Gavin

[mrlex]

Dash has no life, the main light works with the headlights and the speedo, but no tacho and warning lights, indicator lights on the dash etc...

I understand what your saying ill check the battery life, disconncted.

I checked all the wires off the alternator and battery just now...
When cars off...battery and alternator read 12.36
Start car and let it idle, both read...11.something
The thin blue wire off the alternator reads..0?
Give it a rev and the blue wire reads 13.76 the battery 13.49 and main alternator wires 13.74
Lights and blowers on! alternator...13.70, battery...13.28

What does this blue wire do?
If disconnected it doesnt have an effect on the car running, I also pulled the + Terminal off the battery whilst the car was running and it still runs...risky test but I had to try every option.

[h100vw]

Dash has no life, the main light works with the headlights and the speedo, but no tacho and warning lights, indicator lights on the dash etc...

I understand what your saying ill check the battery life, disconnected.

What does this blue wire do?

If disconnected it doesn't have an effect on the car running,

That wire is the excitation for the field windings in the alternator.

http://en.wikipedia.org/wiki/Alternator

You need that connected to get anything out of the alternator at all. You can spin it until the cows come home with no output, until you put something into the field.

It does look to me that the alternator is working as it should.

Gavin

Are the cells in the battery full of electrolyte? If not that would reduce it's capacity. A new looking battery still might not be any good.

[cab93]

Dash has no life, the main light works with the headlights and the speedo, but no tacho and warning lights, indicator lights on the dash etc...

I've had this problem once before, Start as a intermittent fault where the gauges would drop out.

Repaired by removing instrument cluster (including radio) and pushing the wires back into their holder (the wires feed into the cluster). The headlight switch wiring had been routed over the cluster wiring and pulling it out over time.

The Bentley manual states it could also be the Voltage Stabilizer (small black square box with three pins and a small screw holding it.)

With the battery problem, when the car cuts out - do the headlight turn on bright? If the lights are bright maybe the fault is elsewhere. If the lights are dull battery maybe due for replacement.


Michael

[mrlex]

Cheers for the help guys,
Alternator seems to be working for now...
So ill keep a regular check on the power output from both the battery and the alternator. Maybe getting some life back into the instrument cluster will help, theres power getting to a few wires on the main connector, but wont light up any of the warning led's.

I can also see that it has a repair sticker from 1998!

Is there any fuses that control the cluster or does it all work off the power in the circuit on the back?

Thanks again
Alex