Larger nozzles may burn "hotter" or dirtier, sometimes producing more soot or black smoke. When Injectors Physically Overheat
If your engine starts fine when cold but won't start when hot, pour cool (not ice-cold) water over the hydraulic head of the injection pump. If the engine starts immediately after, the internal pumping head is worn and the pump likely needs to be rebuilt or replaced. Verify Fuel Supply & Pressure Lift Pump Check bd2 injector hot
On heavy-duty engines, the injector harness runs along the valve cover. Vibration can cause the harness to chafe against metal brackets or the rocker housing. If the BD2 injector wire (usually a signal return or high-side driver) contacts a constant 12V or 24V source, the injector will remain energized, overheating rapidly. Larger nozzles may burn "hotter" or dirtier, sometimes
Understanding the root cause is essential to a permanent fix. Here are the most frequent culprits: Verify Fuel Supply & Pressure Lift Pump Check
Measure the fuel returning from the fitting at the top of the pump while the engine is at idle. If the return quantity exceeds 450 cc in one minute