(1) Check the plunger has no scars and rust phenomenon, if necessary, replacement of new products. (2) Check the plunger's matching situation. Insert the plunger end head into the plunger sleeve, tilt about 60 °, if the plunger can slow down under its own action to fit well.
(3) Check the sealing of the plunger pair. Hold the plunger sleeve with your hand and two fingers to the top of the plunger and the inlet of the side. Use the other hand to pull out the plunger, feel a greater suction, relax the plunger immediately retracted in situ, indicating that the plunger pair is well sealed, or should be replaced by the plunger.
(4) Check whether the valve pressure band is wearing a step or scar phenomenon, if necessary, should be replaced.
(5) Check the matching condition of the valve pair. With the finger block out the valve under the hole, with another finger will be out of the valve gently downward pressure, when the finger away from the top of the valve, it can automatically rebound in situ, indicating that the valve is a good seal, or should be replaced by the valve deputy.
(6) Check the tappet body. The standard gap between the fuel injection pump body and the tappet body is 0~0.03mm, if more than 0.2mm, the parts should be replaced.
(7) Check the plunger flange and the control sleeve gap between the groove, should be 0.02~0.08mm, such as more than 0.12mm, must replace the control sleeve.