Analysis and overhaul of diesel engine operation abnormal failure

A Model 6135D-3 Car OBD2 Tools diesel engine found in diesel engine starter its idling ride, and airframe vibration and sound operation of mildly abnormal. Run 2 min, the diesel engine gradually increases the speed to 1000 r / min, the fuselage vibration is very serious, and the inertia oil bath air filter installed 1,2 cylinder at the mouth outward jet and a small amount of oil mist abnormal, diesel engine running sound.

Fault diagnosis: the above scenario, the presence of training instructors decisively ordered an emergency shutdown, an inspection of the diesel engine, found close to 5,6 cylinder intake manifold fever, but not hot close to 1,4 cylinder intake manifold; open the valve chamber cover, found 5 cylinder exhaust valve rocker adjustment screw loose, car diagnosis tool resulting in excessive valve clearance, and has more than valve lift; disassemble the cylinder head to check and found the five-cylinder piston top surface "ω"-shaped pits within area there is a small amount of diesel.

Failure Analysis and Troubleshooting: analysis based on the inspection results, the diesel engine failure due to the five-cylinder exhaust valve lock nut not tightened as the long-running loose, leading to the exit of the adjustment screw, the exhaust valve clearance gradually increases. Valve clearance over the valve lift, so that the exhaust valves of the cylinders is always in the closed state, resulting in the end of the car key programmer exhaust stroke, the cylinder pressure increases, the running resistance of the diesel engine increases, so the vibration occurs and running unstable, while also affect the normal combustion cylinder and work output. In the subsequent intake stroke, since the intake valve advance on the high temperature of the cylinder, the high pressure gas through the valve and the intake pipe is discharged from the air cleaner filter small amount of oil of the oil sump is brought out.

Re-adjust valve clearance in accordance with the provisions of torque locknuts supplemental oil and oil tanks to the air filter, diesel engine work to restore normal.

Work experience: OBD2 Code Scanner the diesel engine repairs and adjustments, be sure to methods and procedures in strict accordance with the instructions provided for the implementation of the operation to ensure that the diesel engine threaded locking device and reliable. Through this case, failure to exclude the author appreciate the correct operation and careful maintenance, maintenance personnel must master basic skills, is to avoid or reduce the failure to extend the service life of the diesel engine, and give full play to the basic guarantee of the effectiveness of such.