[jr_ss]

The Defi oil pressure gauge is going to light up and beep when the car isn't running. There's no oil pressure so the gauge is saying you have a problem. The car must be running for you to have any oil pressure. I don't know if you bought the gauges new or they came with the swap but, If you did buy them new, you should read directions or actually do some research about the Defi oil gauge beeping and flashing...

As for the gauges causing your car not to start, I highly doubt it unless you spliced in the the ignitor wiring, which is almost impossible to do. I would try to acquire a factory ecu and see if the greddy unit is the cause or not. If you wired your car yourself, go back and make sure all your connections are right...