Checking Injector Functionality and Replacement

If the engine struggles to start and runs very unevenly after starting, emitting a lot of white smoke from the exhaust, there is likely a problem with the diesel atomisation or one of the injectors is not functioning correctly; start by checking that diesel is reaching each injector properly: unscrew the nut from the fuel line and try to start the engine: if diesel comes out from all the lines, it means it is reaching each injector regularly; then check the return: disconnect the return pipes and attach another pipe into a container for collecting the diesel and assess the volume: start the engine, possibly using a spray starter, and let it run for five minutes; the injectors corresponding to the fullest container are not atomising and not injecting diesel into the combustion chamber: they must be replaced.

Unscrew the fuel lines, disconnect the connectors, unscrew the pin from the injector mounting bracket, remove the bracket, and then the injector; install the new ones, taking note of the code and reversing the steps.

By repeating the return check, you will notice that the two new injectors recover very little while the other two do not: it would have been advisable to intervene on all four injectors.