Ignition Coils Ignition related faults are indirectly monitored via misfire detection. The are no specific checks of the primary circuits. Fuel Injectors An electromagnetic, top feed fuel injector is installed in each cylinder inlet tract of the inlet manifolds. A common fuel rail supplies the injectors with fuel from a returnless fuel delivery system. The fuel in the fuel rail is maintained at 3.5 bar above inlet manifold pressure by a pressure regulator incorporated into the fuel filter. A Schraeder valve is installed in the fuel rail, to the rear of injector No. 7, to enable the fuel pressure to be checked.