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MG MGB Technical - Dodgy ignition light

Ignition light glows brightly, goes out immediately on start-up. Batteries are quite new, can start the car after being laid up for a month (ie this afternoon).

Drove around for a bit (an hour), switched off the engine and then single click when I try to restart. Happened half a dozen times. Then, without reason, the engine turned over and the engine started.

Battery and earth connections are good.

The ignition light glows dimly as engine load (LOAD, not speed) increases. In neutral, revving the engine has no effect on the light. In gear, giving it some welly makes the light glow very dimly. The radio (modern digital job) switches off, comes on again when engine load comes off.

No misfires or engine problems, all the electrical stuff (radio excepted)

Batteries show 13v with engine switched off. At idle, same connection shows 13.5v. If I then rev the engine, the meter (digital) goes wild.

Any votes for anything other than an alternator??? Any thoughts on the starter relay?

Thanks in anticipation,

Neil Lock

Hi Neil.

What year is it ?.

Carefully check your engine earth strap, a problem here could cause both alternator and starting problems, and could vary as the engine revs / load change.


mg specialiste problem some time a go,i found a dodgy earth connection next to the coil bolted to the body ,after cleaning and re greasing problem solved. iff the light gets brighter when reving change the alternator ive just purchase a new one

Don, Its a 1970 with a 16ACR alternator Earth straps and earth connection are fine.

Daz, I've ordered a new alternator. Batteries seem to be unavailable, so let's hope it's a dodgy alternator!


This thread was discussed between 23/04/2006 and 25/04/2006

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