1`st turbo
Turbo Mini Forums

hi there ive just spent 12 months building myself a mini using a 1990 mg metro turbo as a donor fitting wiring loom ,engine ,ect ,ect could any one tell me why when i switch on the ignition the fuel pump runs constantly and when i disconnect the oil pressure switch the fuel pump does run at all .
is the oil pressure switch supposed to be linked to fuel pump .
any help or response would be greatly appreciated .
thanks

The metro loom incorporates a feature to protect the engine in the event it loses oil pressure, this works by only allowing the fuel pump to run when the engine has oil pressure sufficient to switch the light on the dashboard out.

However, the Metro turbo oil pressure switch works differently to any other A series oil pressure switch, what I suspect you have done is fitted the wrong type of switch to your engine. The easiest way to correct this is to get hold of a PROPER metro turbo oil pressure switch.

When the electrics are working properly, the fuel pump does not run with the igntion switched on and the engine stopped (as there is no oil pressure) to allow you to start the engine, when you turn the key to the "start" position, this energises the fuel pump relay, which allows the pump to run, and build up enough pressure for the engine to start up. As soon as the engine has started up, the oil pressure switch then switches the relay, which turns the pump on constantly.

If you have a good look at the wiring diagram from the metro you will be able to see how the circuit works in the manner I have described.

Edited by Tom Fenton on 3rd Nov, 2005.

thanks you have answered my problem and cost me more money . cheers mate .