Cummins Generator Is Difficult to Start?

by Starlight Generator dieselgeneratortech

1. Diagnosis and treatment of Cummins engine starting difficulty or failure to start and exhaust pipe emitting a large amount of ash and white smoke.

The engine is difficult to start, and the exhaust pipe discharges a large amount of gray smoke, which is diesel vapor.

Reason

a. The engine temperature is too low, diesel oil is not easy to evaporate and burn.

b. Poor atomization of injector

c. The oil supply is too late.

d. The oil supply is too small and the mixture is too lean.

e. Cylinder leakage is too much, compression can not reach the ignition temperature.

Diagnosis and treatment

a. If the engine temperature is too low in cold season, check whether the low temperature starting preheating device fails, that is, whether the preheater control circuit has open circuit, short circuit or preheater failure.

b. If the low temperature preheating device is normal, check whether the injection timing is correct. Turn the engine and insert the engine camshaft timing pin, that is, when it is located at the upper dead center of cylinder compression, check whether the fuel pump camshaft lock pin can be inserted. If it cannot be inserted, it indicates that the injection timing is wrong and needs to be adjusted.

c.The spray quality of each cylinder injector should be checked to meet the requirements.

d. If the first two items are normal, check if the oil supply is too small. During cold start, due to the low temperature in the cylinder, the fuel viscosity is large, and the evaporation condition is poor, the starting oil supply is required to be larger than the rated oil supply.

e. Finally check the cylinder pressure and repair it when the pressure difference is very far.

2. Diagnosis and treatment of engine starting difficulty or failure to start and exhaust pipe emitting a lot of black smoke.

The engine is difficult to start, and the exhaust pipe emits a large amount of black smoke, which is the result of incomplete combustion of the diesel oil.

Reason

a. Diesel oil is of poor quality.

b. The air intake is not smooth and the air filter is blocked.

c. The injection timing adjustment is too early.

d. Injector needle valve sealing is poor, there is dripping oil leakage phenomenon.

e. The injection pressure is too low

f. The fuel supply of the fuel injection pump is too large and the combustion is deteriorated.

g. Low cylinder pressure and poor atomization.

Diagnosis and treatment

a. Determine if the diesel quality meets the requirements.

b. Check if the air filter is clogged.

c. Check if the injection timing is too early. Turn the engine and insert the engine camshaft timing pin, that is, when it is located at the upper dead center of cylinder compression, check whether the fuel pump camshaft lock pin can be inserted. If it cannot be inserted, the fuel injection timing is wrong and needs to be adjusted.

d. Check whether the fuel pump supply is too large.

e. Check if the fuel injection pressure and spray condition of the fuel injector are good, and the fuel injector should not have a dripping phenomenon.

f. The working condition of each cylinder shall be checked by the oil-breaking method.

g. If the above inspection is normal, but the fault remains, check whether the cylinder pressure and piston, piston ring and cylinder clearance are abnormal, whether the cylinder gasket is damaged or the valve is not tightly closed, etc.

3. Diagnosis and treatment of engine thermal starting difficulties

The cold start of the engine is good, but after running for a period of, temperature rises and the engine turns off. It is difficult to start again.

Reason

It is mainly caused by serious wear of plunger pair of fuel injection pump and needle valve pair of fuel injector. When the hot car starts, the fuel viscosity is reduced due to the high temperature of the fuel injection pump and fuel filter, and the starting speed is low, and most of the diesel oil leaks from the worn gap, resulting in insufficient starting oil and unable to start.

Diagnosis and treatment

a. The method of emergency elimination is: the car is hung up and driven by other cars. Using the speed of the car to drive the high-speed rotation of the engine, so that the diesel can not leak, to ensure the starting fuel supply (this method is not recommended, because the cylinder pressure of Cummins generator supercharged engine is relatively large, the impact force on the connecting parts when the trailer starts is large, affecting the vehicle service life).

b. When the plunger pair or needle valve pair is seriously worn, the new product should be replaced after the inspection and debugging of the fuel injection pump test bench.