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MG MGF Technical - Flat Batteries

I have bought a brand new battery, fully charged, yet in three days it was dead. Could it be
a) A diode problem in the alternater ( rectifier)
or
b) A problem with the ECU

Any help would be appreciated

Thanks
Chris

Yes
Will Munns

Oh go on then....
a) unlightly

b) possible, the ECU has a circuit which is powered on after ignion off for a short while, search the archives for power window delay circuit, the wire to test is here, and should stay on for about 10 mins IIRC, to operate the fans etc.

Also
c) Have you left a light on, obvious I know but the lights under the mirror are difficult to see in the summer

d) Is the alternator actually charging?
Will Munns

(e) bought a dead battery
(f) boot or bonnet light remaining on

Regarding prolonged power-down of the ECU, have a look at Dieter's web page: http://www.lame-delegation.de/mgf-net.de/power_delay_by_carl/index.htm
Rob Bell

If you have been using the car evey day then I wouldn't think it was the MEMS ECU 'sticking relay' problem causing it. The battery, especially a new one, should be able to deal with that discharge for one night easily.

Probably more likely to be a faulty alternator or a broken alternator lead. Have someone check the voltage while you run the engine at 1500-2000rpm. After a few minutes the voltage should be well into the 13 volt area.

Bruce
Bruce Caldwell

14.5v?

If the alternator is compleatly unplugged then you wouldn't get charging, but you would also be missing a red light, both before and after you had started the engine.
Will Munns

Will,

Mine suffered with a broken main lead from the alternator. It made very intermittent contact but the ALT warning light never came on once. The battery eventually became flat and the car refused to start. If the wire had shorted to chassis I expect the car would have caught fire.

Is the regulated voltage 14.5 these days? It used to be 13.6 when I 'were a lad'

:¬)

Bruce
Bruce Caldwell

This thread was discussed between 19/05/2003 and 21/05/2003

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