Cheers for the comment Andrew. I have wired up the fuels with a negative trigger off the Auxilary Outputs via a relay. I have a few relays setup in the 12V power delivery, and all are negatively triggered by the computer. The only one seperate is the main ECU relay which is cranking ingition triggered relay and then this one feeds power to the other relays coils. The diode for the fuel pumps was in the 12V feed straight to the pumps. I am running twin bosch pumps so I am assuming that the amount of Amps drawn by these pump would be rather great and the diode only was a 5 Amp one.
Cheers
Wombat