I doubt it's that serious, yes the fuel pump primes from the CPS signal dependant upon temperature as well, if it's a warm start it may not prime as it is not considered neccessary, It should prime after being left over night.

Easy way to test if the valve is working is to listen for a 'Click' when ignition is switched on but of course if the pump isn't priming then the amal won't be live.

In this case when engine is running remove the electrical connector and either listen or put a finger on the valve it should give a noticable click.

The ISCV also gets it's feed from the fuel pump relay.

Do you know what boost your running? Standard boost is 0.7/0.8 BAR.

Have you changed the CTS (Coolant Temperature Sensor) these go out of range after a while so it's worth changing as this is an important input.


Martin