Voltage and engine varying swinging up and down!

Today, started the car to go to No-Rice, waited a sec for engine to settle down before giving a quick blip, and instead of settling nicely, the light went out, and the voltage (VDO gauge) swings wildly between -ve and +ve! Engine sounds like its varying as well.

What could cause this, it happened after I washed the car and it was fine on way to work and back/

Its a Mk1, running a 16V on mk2 K-Jet ECU. Could a wet ecu/tci cause it? (noticed some small amount of water on it unlike normal). Screwed Voltage reg? Deceased Alternator?

Ok, i've had a minor prob for ages, after I installed a new voltage reg I have had to give it a quick squirt of revs to get the battery light to go out (stands to reason, to get the voltage high enough to flip the voltage reg I assume). I had assumed that I needed to strip alternator down and clean contacts, but havent had time.


I haven't a clue…

Dave

Hmmm. I seem to have got a similar problem. Having been fine, after getting MOT'd yesterday the vdo voltage guage is filckering from 14v to 17v with the engine running. If I put some load on (turn on headlights, blower fan etc) the voltage seems to stabalize. Turn tham all off again and it flickers again.

Got to be something to do with the rain. Fan belt has started squealing slightly too. Going to tighten that up, hose the lot in wd40 and see if that helps after the football!

Either that or a new alternator is required…

Reckon it is my voltage regulator that ha gone. Readings fluctuate between 14.3 & 14.7 when measured at the battery (which doesn't seem like a lot) but the vdo needle is going crazy! The battery light also flickers on & off very slightly.

Only ?10 so will try that first and see…

Hi Woza,
Would be interested to see how you go with this. I had a new voltage regulator fitted a couple of months ago because the voltage wwas going all over the place.

However, in the last couple of days it swings > 14V when the car starts - only does it for the first few minutes. I spoke to a friend who is an auto electrican and he says it's probably to do with the windings on the alternator. If the voltage is unstable all the time, then he reckons it's the regulator, otherwise windings.

I'm going to monitor it and see how I go.

P.S Thanks for the PayPal email - will sort out tomorrow!!

Will let you know. Mine are fluctuating all the time so I will try gsf for a replacement - VAG didn't have any in the country…

Fitted a new voltage regulator from eurocarparts (?10) (vw had none in the country) and everything is back to normal. 13.91V stable.

Think the bushes were just worn too far down…