5 replies to this topic

[dan1zo]

Hi all, i have a bit of an odd problem with my Cooper.

When i'm driving along, my voltage reading on the dashboard appears to read only just above the red. But when i come to a stop, the voltage returns to where it should be.

There are times when driving that i can accelerate and lift off and the voltage seems to return to normal, but only for a little while. The dial then returns to just on the red as i continue to drive.

I thought the problem was my battery or alternator, so i got myself a voltmeter and checked across each. I cant remember the exact readings but they matched what they should be when i checked somewhere else on this site.

I've not been able to connect up the voltmeter to the alternator while driving (i dont fancy trying to hang it out and read it and drive at the same time).

While i was at it i cleaned the earth connections and connections to the alternator. But that seemed to make no difference.

Any help at all people, this is driving me nuts. I have to leave him to run for a minute or two when i stop, just so that he'll start up in the morning!

Cheers

[minicooper1.3i]

Have you checked the tension and condition of the fan belt? If you're getting the necessary 13-14V at idle but dropping when reving, it could be your fan belt slipping.

[dan1zo]

Hi

Yeah brand new tightened fanbelt too.
When revving it is ok, its when i actually start driving.

Funnily enough, if i coast along with the clutch down (no drive) it still doesnt charge. Its only when i come to a stop that it charges again. :S

Its bizarre, its as if the alternator isnt producing a charge while i'm driving :S

If there was an issue with the alternator, wouldnt it have a problem when idling stationary too?

[dan1zo]

Ok a bit of a result last night.

I thought i'd have a quick nose round the engine bay for frayed wires etc, just in case there was a short somewhere.
I had been checking the usual places around the alternator, starter motor and found nothing.

So i just started following wires and i found a whole bunch of wires just behind the air filter housing.
It seems that the bunch of wires has been rubbing on one of the filter housing spring clips. One wire was sheered through, and 2/3 others had the wire casing worn away.

I checked the trusty Haynes and found that one of the frayed wires went to the voltage regulator, so that probably explains the erratic voltage i have been getting.

One wire, a red and purple one, was sheered right through. I couldnt find what it was for in the wiring diagrams.
Does anyone have any idea what it connects to?

Cheers

[minicooper1.3i]

Not sure off the top of my head. Check in the Rover manuals (pdf's) posted at the top of this forum. They've got pretty good colour diagrams.

[dan1zo]

Sorry, i'm new to the site.
Could you let me know where i may find them please.

Thanks