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MG MGA - Regulator-voltage output.

First the problem.

I have an ammeter and voltmeter which are working fine. The ammeter flicks up when I rev and the voltmeter shows about 13.5 cruising, or they did till yesterday.

I noticed for the last week or so it took about 5 minutes of the car running before the ammeter and voltmeter showed the above behaviour. Until then the voltmeter would stay on 12 volts and the ammeter wouldn't give its flick up when revved.

Now the volts don't go above 12 and the ammeter just stays still, doesn't show charge when revved. Charging light shows its normal behaviour.

Regulator problem do you think? If I didn't have the ammeter and voltmeter I wouldn't be noticing anything different.

Hope the above makes sense.

Chris.
Chris C

First things first--check your ammeter and voltmeter installation for loose wiring, grounds, or other damage. (This is assuming that they are an installed, aftermarket item.) Then check your generator and reg with a good analog instrument IAW the workshop manual. Aftermarket dash gauges are not always that accurate. Checking with digital voltmeters is not as good--as there is a lag between the input and the reading. You may miss fluctuations or spikes, as they tend to average.
R. L Carleen

Chris - The first thing that caught my eye was a "normal" reading of 13.5 volts. This is about 1 volt lower that what is considered normal. As RL suggests, check your instruments to insure that they are not leading you astray. If their readings are good, then I would suspect the regulator or the generator in that order. Cleaning the contacts and making sure that all the connections (even those connections through the straps to the terminsls) that are made with a rivet through them. If that fails to find the problem, then a trip to a good auto electrics shop would be in order. Good luck - Dave
David DuBois

Well that was a quick fix.

Regulator cut out was stuck open. Cleaned it up and everything is now back to normal. Cicks in at about 1000 revs now which I believe is about right.

I will also check the voltmeter David. Could just be a bit out.

Only fitted these gauges a month ago and they have already proved useful.

Thanks all.
Chris Paul Currah

This thread was discussed on 09/05/2005

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This thread is from the archive. The Live MG MGA BBS is active now.