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MG MGB Technical - Mr Miyagi Says - 'Lights on, Tach off'
Hi guys, anyone remember the film the Karate Kid, Mr Miyagi says "Wax on, Wax off". Well i have similar problem, although it envolves no wax! Every time i switch on the lights on my 71 BGT the tachometer dies. Switch them back off & it comes back to life. Any ideas where i should start looking. I am not sure if this is related but my fuel pump sometimes seems to stop pumping. This happens randomly & not very often. I am going to start by checking all the electrical connections to the pump, but if anyone has any other ideas i would be glad to hear them Cheers Scott |
Scott Ralph |
Scott, it may be a bad ground on the lights. When you click them on, it grounds through the tach (the tach feed on your car is, I believe, negative). The current coming down the line throws the tach all outta whack. I would try re-earthing the lights (just hook up a grounding wire to the black wires coming back from the lights). |
Dan Fields |
Bad ground to the tach. With the lights off the tach grounds through the lights. With the lights on there is no ground left for the tach. There should be a black ground wire secured under one of the thumb-wheels that secures each gauge in the dash. |
Paul Hunt |
Thanks guys, is was a bad ground, one of the thumb wheels on the back of the tach had worked loose. Tightened it up & all working again. If only all problems where as easy to fix as this! Cheers Scott |
Scott Ralph |
Don't forget the fuel pump!!! It sucks fixing it on the side of the road! It will usually go @ night in the rain!! Check the connections, but also suspect the points. It has been my experience that a SU fuel pump is good for about 5 years before the points start to go. I switched to the new SU with the electronic points, so far so good. |
Robert Dougherty |
This thread was discussed between 20/05/2002 and 22/05/2002
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