单项选择题
A.cold intake air
B.excessive compression pressure
C.excessive cylinder lubrication
D.a light load
单项选择题 Because of the close tolerances used in diesel engine fuel oil pumps, a worn plunger requires（）
单项选择题 Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（）
单项选择题 Piston compression rings used in a diesel engine function to （）