Cutting-out & misfire
QI have a 2009 Citroën C5 2.0 HDI. Every now and again the engine seems to have a misfire and feels like it’s going to cut-out when accelerating. Sometimes it cuts-out all together when pulling up to a junction with no dash lights on at all – as though you have just turned the ignition off.
Sometimes it can take three or four attempts at starting. As soon as you let go of the key on starting it cuts-out. I have plugged in my code reader and diagbox but no codes are coming up at all. I have heard it could be one of the fuel pressure regulators or even the EGR valve. The vehicle has been serviced recently with all filters renewed. Any help would be appreciated.
Steve Dickinson
AGiven the symptoms you describe indicating that the dash light are also extinguished when the problem is present, and the problem with the starting I would suspect that the fault is the ignition switch. This would give the symptoms you have and this would also not leave a fault code in the ECU.
Another possibility as the problem will occur when under acceleration is that a wire or earth lead from the engine has failed and is breaking the circuit when the engine moves. This may be a main earth lead or one of the smaller leads in the engine loom. It may be possible to check for this by carefully giving the loom a shake with the engine running to see if the engine revs are altered at all.
Although the fuel pressure regulator or the EGR valve could allow a misfire, this would not also extinguish the dash lights and would also normally leave a fault code in the ECU.