Wire fuel pump with oil pressure control
Turbo Mini Forums

This is how I'd recommend wiring up a fuel pump. It's done through the oil pressure switch (old type ofcourse) and means that at the loss of oil pressure the fuel pump won't work.


De-energized circuit - Engine not running




Energized circuit - Engine not running




De-energized circuit - Engine running



Open to all comments and critisim.

Cheers
Quinton

http://photobucket.com/quintonrose

Thanks for the info, good advice to set your fuelpump to run like this if the ecu is not controlling it.

Team www.sheepspeed.com Racing

And don't forget the inertia switch

does the fuel pump connect to the relay positive or negative

what about residual fuel in the carb bowl? or is this an efi thing?

It's not an efi thing, with virtually all efi systems (even if they are only wired for ignition and not injection) they run the pump for a couple of seconds when the ignition is turned on then stop it until an RPM signal is read from the trigger wheel (ie, cranking/running).

As soon as the RPM signal is lost (ie, engine stops for whatever reason), or the ignitioin is turned off, the pump is shut down.

Using oil pressure to determine whether an engine is running or not is a non-ECU based system.

Schrödinger's cat - so which one am I ???

I use just an inertia switch - PITA if you hit a big bump, but at least its fail safe

Two things, you may need to weaken the spring in the relay to allow the contacts to close firmly. The reason for this is the oil pressure circuit is a low power circuit and you may hear the contacts flutter. You also have to crank the engine until it builds oil pressure to cause the relay to de-energise and switch the pump to run and the current draw of the starter won't leave much to switch the relay.

This exactly how mine it's wired in.

Point 2 make sure you have a good battery and starter.

Edited by Mr Joshua on 25th May, 2012.

Own the day

rod s, i see makes sense kinda dum on my part haha..

mr joshua, is it posable to install a wire from the starting circuit ie when the key is cranking to over ride the pump cut out? that would give you flue when cranking before the oil pressure gets up