Diesel Engine Fuel System Fault Diagnosis Analysis

Diesel engine fuel system fault diagnosis analysis (the next section will focus on explanation in the form of examples)

a. There is air leakage in the low-pressure oil circuit (use a drip method, if the oil delivery volume meets the requirements, it means there is air leakage in the low-pressure oil circuit, and the following components should be checked):

(1), Oil pump inlet pipe; (2) Diesel filter (the diesel engine has insufficient power, the filter element should be checked and cleaned first); (3), Diesel filter oil inlet pipe, (4), Hand oil pump (most problems occur here) ; (5) Fuel tank vent (for air exhaust, check if it is clogged); (6) Fuel tank (the fuel tank suction pipe is welded to the tank body, and cracks or pinholes in the weld will cause air to leak into the fuel system. This is often overlooked).

b. Speed regulator failure (the manufacturer has adjusted it and no one can touch it)

c. Smoke limiter failure (it is a component that affects the performance of the diesel engine. It has been adjusted by the manufacturer and no one can move it, otherwise it will affect the diesel engine power and exhaust smoke)

The smoke limiter located on the smoke limiter uses the air pressure in the intake pipe to adjust the air-fuel ratio to achieve the purpose of controlling smoke. Damage to the smoke limiter will result in insufficient power and increased smoke exhaust. If the air pipe from the intake pipe to the smoke limiter is leaking or blocked, it will also cause power reduction and increased smoke exhaust.

If the vacuum tube on the smoke limiter breaks, the power of the diesel engine will decrease.

d. The low idle speed adjustment screw of the diesel engine can be adjusted (if the low idle speed is too low, the engine will coast at idle speed). Be careful: the high idle speed adjustment screw must not be moved at will, otherwise it will cause the engine to spin.

e. To determine whether a cylinder is not working, the cylinder disconnection method can be used to check. After determining which cylinder, remove the faulty injector for debugging, and check whether the injector is equipped with an extra sealing copper gasket. At the same time, check whether the fuel injector is faulty, and you can connect it to the outside of the engine for testing.

f. Oil return (you can check the oil return amount of the diesel engine at rated speed to determine whether there is a problem with the oil circuit).