ive just got my s2 rst engine in after being rebuilt and tried to strike it up today but it wouldn't fire. after closer inspection we found the metering head wasn't sending fuel to the injectors. we cracked the other connections to the metering head (cold start valve, filter outlet etc) and we got fuel. the sensor plate feels a bit flimsy but im not sure what tension should be on it

im thinking the plunger maybe ceased ??

any ideas ??