Luke968

Sorting out a few gremlins in electrical system at present which the forum has been very helpful with understanding.

I have seen on a different web site where they suggest testing the alternator by removing the voltage regulator and jumping the alternator's positive and field pins. A reading of around 16V at the battery terminals indicates the alternator is OK.

Whilst they suggest doing this for only a short period of time, I was wondering if this is indeed safe for any period of time or could you fry something ?

Cheers.

RajDatta

This is by no means the easiest way of testing an alternator. 1st off, you would have to remove the voltage regulator, no small feat (requires removal of parts of intake).
What exactly are your symptoms?

Luke968

Thanks for your response.
Recently, when first turning the ignition on, the voltage meter doesn't move and the meter warning light is on. The car starts no problem and the meter slowly moves up to 13.5V .
Over about the next 15 minutes, the meter drops to 12.5 and once the high speed cooling fan kicks in it drops striaght down to under 12. Idle or high revs doesn't change the reading. I haven't driven it for more than half an hour at a time with this problem, during which it runs fine and no problems starting it the next day.
I have cleaned up all the grounds I could find, cant find the internal firewall one for the fuse box, think I will have to track it down from the top. The battery is less than a year old and I have replaced both battery leads.
My test meter has died so I'm getting a new one today.
From the forums, this appears to have been a problem for several people but I haven't found where a cause has been nailed out right.
Thoughts would be appreciated.

Cheers.

RajDatta

I had a similar problem and it turned out to be the cable that connects the alternator to the starter. The connector on the alternator end had turned corrosive from coolant leak from the throttle body. Also, protective seathing was lost and the cable was full of corrosion. It is not the easiest cable to get out but I would check resistance on that.

Luke968

OK, I'll attack that over the weekend and let you know how I get on.

Thanks for the advice.

Cheers,
Luke

Luke968

Problem solved.
In the end it was the voltage gauge.
In the meantime I put in another new battery and had the alternator rebuilt (which was needed anyway as it was starting to get noisy) and managed to find every ground cable location and cleaned them up but the problem persisted.
The gauge was showing what the battery was showing with the multi meter both with the engine off and at idle but would slowly die to 12V when on the move.
Changed the gauge out for another one and it shows just over 14V when first started dropping to just under 14V with all accessories on and stable at that thereafter.
So much nicer to drive the car without one eye constantly on the instrument cluster.
Thanks to all who contribute to the forum, it was a great help in eliminating/tracking down where the problems might be.
Cheers.

RajDatta

Cheers. I know the feeling since I would show almost under 12 volts with all accessories and after a bit of driving. Love that it remains over 13Volts the entire time now.