Rev counter

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Jason
Posts: 2
Joined: Wed May 19, 2021 9:14 pm
Forename: Jason
Surname: Watkin

Rev counter

Post by Jason »

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
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Steven collins
Posts: 123
Joined: Fri Oct 31, 2014 5:20 am
Forename: Steve
Surname: Collins
MGCC Member: Yes
MGOC Member: Yes
Location: North Essex

Re: Rev counter

Post by Steven collins »

Jason,
RVC should have 3wires as per photograph
70E5347B-9F3F-4CEC-B95A-0381FB7BF3A8.jpeg
Hope this helps
Jason
Posts: 2
Joined: Wed May 19, 2021 9:14 pm
Forename: Jason
Surname: Watkin

Re: Rev counter

Post by Jason »

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!! 🤔
User avatar
Steven collins
Posts: 123
Joined: Fri Oct 31, 2014 5:20 am
Forename: Steve
Surname: Collins
MGCC Member: Yes
MGOC Member: Yes
Location: North Essex

Re: Rev counter

Post by Steven collins »

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.
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