What causes sprinkler diesel engines to inject fuel too early/late?

When a diesel engine in a water truck emits rhythmic and crisp metallic knocking sounds from the cylinders, overheats, lacks power, emits black smoke, idles poorly, or fails to start, it is generally caused by premature fuel injection from the fuel pump.

The fuel injection in a diesel engine is controlled by the injector. Premature fuel injection can occur due to reasons such as loosening or displacement of the connecting plate and fixing screw. Improper adjustment or movement of the timing adjustment screw for the plunger rod inside the fuel pump can also cause premature fuel injection. During inspection, loosening the fixing bolts of the fixed plate and gradually delaying the fuel injection timing can help diagnose premature injection if the condition improves.

The phenomenon and reasons for delayed fuel injection in the diesel engine of a water truck are as follows: If you hear a low and indistinct knocking sound from the cylinder of the diesel engine, if the engine speed of the water truck cannot increase rapidly with the increase of the throttle opening, and if the engine overheats, lacks power, or emits white smoke, these are all caused by delayed fuel injection.

The reasons for delayed fuel injection are as follows: The semicircular key of the fuel injection pump drive gear slides or is improperly installed. The connecting plate fixing bolts are loose and dislocated, causing the injection timing to be off. The timing adjustment screw on the plunger tappet of the fuel injection pump is misadjusted.

What is the phenomenon and cause of excessive diesel fuel injection, and how to eliminate? When the diesel engine is over-injected, the following fault phenomena will occur: a large amount of black smoke is discharged from the exhaust pipe. After the engine speed increases, the speed cannot be reduced immediately after the accelerator pedal is quickly released.

If the sprinkler encounters an obstacle at high speed, the speed cannot be reduced immediately when the accelerator pedal is quickly released. The reasons why the sprinkler injects too much oil are: the injection volume of the injection pump is adjusted too large, and the pump rod stroke is too small.

The inspection and troubleshooting methods are as follows:

1. While the engine of the water truck is running at high speed, quickly release and then depress the accelerator pedal. Touch the high-pressure fuel pipe by hand. If the fuel pipe still feels pulsating, inspect the throttle cable. Adjust it appropriately, and if the condition improves, it indicates a successful adjustment.

2. If the adjustment is still ineffective, it is necessary to test and adjust the fuel injection pump on a test bench.