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MG MGB GT V8 Factory Originals Technical - Electrical Problems

Although this is my first posting on this BBS I've been reading, and following the advice from the much more experienced people in this area.
I'd like to thank you all for providing highly useful information, which allowed me to achieve my goal in the conversion of a 1980 MGB. The conversion which I speak of may be very simple compared to what some of ya'll(I'm from Texas) have achieved. Basically it consists of a 1963 Buick 215 with a four barrel Carter a mild cam and valve springs. I also bored out the cylinders .030". The engine is equipped with a small gear ratio starter(D&D Fabrications) and an AC Delco alternator.
The problem I'm having is an electical one, where the engine will crank, but will not fire. Also, the fuel pump will not come on. However, if the fuel pump is fed current directly from the batttery it will come on. Also, when I first tryed starting the car the ingnition points fried. After replacing the points, and trying to start the car again, the wires at the starter relay cooked.
At this point I stopped what I was doing.
Any help would be appreciated.

Galliano Macalle
Galliano Macalle

Late MGBs had an interia switch to cut power to the fuel pump in an accident. This can trip out with lesser knocks, I believe it is mounted near the RH passenger footwell with a reset button protruding into the footwell. There may also be a similar mechanical valve in the fuel pipe.

Are you sure it was the starter relay (brown, black, white/brown, white/red) and not the ignition relay (brown, black, white, brown/white)? If it were the ignition relay then your other three problems would tie up to a likely single cause. The cause being the coil is shorted out in some way, either with incorrect wiring or internally.

What ignition system have you got? What coil (12v or 6v)? And how have you dealt with the white, white/light-green, white/blue, black, white/black and yellow/red wires that were variously found on late models?

Paul Hunt

I'm using a 12 volt system, and after looking at the car once more I've realized, according to your responce, that it was in fact the ignition relay that burned up.

When I got the car, the previous owner had already dug in to the wiring system, which really adds to my confiusion in terms of the wires you speak of, i.e. white, white/light green, white/blue, black, white/black, and yellow/red.

Is there anywhere I can get a drawing of the cars wiring?

Thanks for your input Paul.

Galliano Macalle
Galliano Macalle

Galliano - you can find schematics of the various factory ignition configuration on the above web site - click 'Spanners', 'Electrics', 'Schematics' and 'Ignition'.

Paul Hunt

This thread was discussed between 06/08/2001 and 09/08/2001

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