Starting problems – Engine starts with difficulty or not at all when cold and/or hot
High fuel consumption – The vehicle’s fuel consumption has increased unduly, but apart from this there is no other fault
High emissions – Emissions above the emission limit values are measured during an environmental test
Performance problems – The vehicle is unusually sluggish and does not respond well to high acceleration
Stored fault codes – The engine control unit (ECU) stores fault codes which are retrieved even after erasure. The above faults can of course also be caused by the failure of other components, so it is advisable to have the injectors removed and tested when conventional instrumentation has failed.
CAUSES OF INJECTOR FAILURE
The two most common diesel injector faults are:
Start-up problems and/or engine stalls under load – Caused in most cases by increased leakage of oil. Most of the cases are due to the fact that the injector is often overheated. However, if the amount of gap oil is too high, the pressure in the common rail will also drop as the injectors are connected in series. In other words, if even one injector’s oil loss is abnormally high, the engine will stall or not start. Uneven engine running – the most important feature of common rail injectors is the amount of fuel delivered. No two injectors have exactly the same delivery, but the engine control unit (ECU) can correct for variations between injectors within certain limits. However, if the difference is so large that the ECU cannot correct it, the engine will run unevenly. This problem is typically caused by the injector nozzle or injector solenoid valve