Look at the pressure, check for leaks
Pressure gauge can be used to measure the cylinder pressure, find out the poor sealing cylinder.Reasons for poor cylinder sealing: valve clearance or clearance is too small, piston and cylinder sleeve and piston ring end face clearance is too large, ring groove carbon.In the diesel engine work, if close to the air filter can hear the "hiss, hiss" blowing sound, then the leakage and valve related.At this point, combined with the smoke situation can confirm the cause of the failure.
Look at the exhaust and check the smoke color
When the diesel engine is working normally, it does not smoke or emit some light gray smoke, sometimes it is difficult to see with the naked eye.If black smoke, it means that the cylinder oil less gas, incomplete combustion.If blue smoke, it indicates that the wear gap between cylinder liner and piston, valve and valve guide is too large;If there is white smoke, it means that the fuel is mixed with water, or the diesel fuel is not completely burned, after vaporization from the exhaust pipe.