MGB Register Forum

Hi All,
I’ve recently bought an mgb with an RVC Rev counter that wasn’t working so I thought I’d have a quick look at it and found the green wire had been disconnected from the back of it, so I reconnected it, turned ignition on and needle went all the way around to 7000 rpm and stayed there(engine off) turned ignition off and needle dropped to zero again, tried this several times same thing happened every time!! Anyone have any ideas what’s wrong with it or how I could fix this problem!!
Thanks in advance
Jason

Jason,
RVC should have 3wires as per photograph Hope this helps

Thanks Steve, the other wires were connected it was just the green one that wasn’t, and when I reconnected it and turned ignition on the Rev counter needle shot around to 7000rpm and stayed there!!

Shorting out somewhere?
Does it do that with the white wires disconnected, i.e. only the green and earth connected, if so then the tach is faulty. If it only does it with the white wires connected then disconnect the white at the coil and see what happens then.