Checking the identity of the fuel supply regulation for each nozzle
On the CUP, select the function «Fuel supply system».
With the engine idling and fuel temperature >50°C, display the fuel delivery rate correction values for each injector, i.e. parameters PR364, PR405, PR406 and PR365 (CORRECTION OF FUEL SUPPLY TO CYLINDERS #1, #2, #3 and #4).
The normal fuel delivery correction value for one injector is about±1 mm3/cycle. This tolerance field may expand over time, but if it goes beyond±5 mm3/cycle, this indicates an injector and/or cylinder failure.
If at least one injector has a fuel correction value > +5 mm3/cycle:
- check the clearances in the valve drive mechanism;
- check the condition of the engine by checking the compression in the cylinders using the Clip Technic or a special tool.
If the compression test reveals a cylinder failure, make the necessary repairs.
If the compression is 8 normal, check the correct installation of the injectors. then check the fuel regulation for each injector again. If the owner's complaint persists, replace the injector.
If at least one of these values < -5 mm3/loop:
- check the clearances in the valve drive mechanism;
- check the level and condition of the oil in the engine;
- remove the injector with the highest correction value.
If diesel fuel is present in the engine oil, check the condition of the corresponding cylinder (cylinder mirror, piston, valves), replace the nozzle.
Note. Before replacing an injector, check that the O-ring is present and correct.
After replacing an injector, and if the individual injector performance correction function is enabled, perform the injector code programming procedure.
Attention! Follow the safety and cleanliness instructions when removing and installing the injector.
Confirming each injector fuel trim diagnosis
Clear the fault or faults from the memory and check that the scan tool does not display any faults within three minutes of engine idling at a coolant temperature > 50°C and that the injector fuel correction values do not reach±5 mm3/ cycle.
If the injector of one or more cylinders has a fuel correction value >±5 mm3/ cycle, follow the diagnostic procedure at the beginning of the section.