The customer supplied a second hand injector today which had a resistance of approx 100 ohms as Tony said.The car now starts & runs fine every time without losing the rpm signal. I've still yet to find the air con relay , which is still coming up as a fault & is what is probably causing the fan to run all the time(very slowly) with the ignition on. Anyway he's taken the car now & will probably bring it back for the aircon problem as the noise of the fan running is annoying his customer. Thanks again to all who helped, Regards, Andrew