Alternator / electrical gremlins?

[tejb1]

Hi all

Apologies if this is covered elsewhere or if it's something stupid and obvious... This morning when I started the Capri up the alternator light comes on, I had moved it just in and out the garage yesterday so assumed that the battery needed a decent run in order to charge properly. After about 500 yards the light went off so I assume all is well.

Stopped after a decent 30 mile trip including a bit on the motorway and on restarting, light comes on and doesn't go off for a good 20 minutes of 30/40 mph driving.

Then stopped again at the supermarket and on restarting, light on and fuel gauge showing almost empty (it's definitely full). Then at a roundabout noticed the indicators not working, which was odd, but again a little later they were OK.

Parked up in a car park and noticed the front left indicator out, tapped the lens and it sprung into life (loose connection?)

I'm assuming there's a short or some other fault that's causing difficulty charging hence the warning. No hesitation starting (it's started 4 times today after various stops with no struggle) so battery seems OK but worried it'll wear the charge down.

Any suggestions as to things to look at in the first instance would be appreciated, will get the multimeter out when I get back home!

Thanks guys

[renaulthater]

Have you tried fusebox/bulkhead connnections?

[tejb1]

Have you tried fusebox/bulkhead connnections?

I'll check them tomorrow and spray a bit of contact cleaner on them. I'll put a meter on the battery to see whether the alternator is doing its job or not.

[r2vdh]

Some alternators can self excite meaning with a engine load/speed they will start to output voltage charge to the battery. Our alternators can do this but to work correctly they require a 12v signal from the car through your igintion light and grounds on the alternator lighting up when the engine is not running.
When you start the engine the 12v from the light excites the alterator into outputing power and in doing so starts putting 12v back to the light from the alt.. This causes the lamp to turn out as there is now no ground/negitve to earth the light.

Turn the igition on and check you are getting 12v to the blue wire on the back of the alternator. If you are then you may have an issue with your alternator regulator.

[tejb1]

Took the fuses out to clean the fusebox contacts and found one fractured which would explain the problem. Got a new fuse in and it's fine, might replace the others as they're all a bit old and probably brittle. Cleaned the contacts with a bit of IPA and fibre brush and all seems good. Thanks all much appreciated

[tejb1]

Another problem has come up since I changed the fuses. After the one which had been causing these problems was changed I examined all the others and swapped out another one which was fractured. (I intend to ultimately change all the others too, I've ordered some more).
Since then, when pulling up at junctions or in slow traffic the revs drop to the point of stalling or almost stalling and it is necessary to apply a bit of choke to keep them up, but even then there is a drop before the choke pulls the revs back up again. Alternatively, when putting the clutch down I can blip the accelerator which avoids the problem. This has only started happening since I fiddled with these fuses and whilst I can't see any connection between the two systems, I wondered if anybody experienced might know of something related or something which I might have disturbed? It was running fine prior to this.
The only other thing which might have a bearing is that I filled it up with some cheap supermarket petrol on Friday when the fuel gauge dropped dramatically (subsequently found it was reading low due to the problems with the fuses as above) and perhaps this had worked its way through, would this have any effect, if I were to drain/use up all the petrol and re-fill with higher quality, or higher octane petrol?