单项选择题
A.increase scavenge air pressure
B.reduce fuel booster pump pressure
C.adjust the fuel rack
D.retard fuel injector timing
单项选择题 What is the best way of stopping an over-speeding diesel engine?（）
单项选择题 The efficient burning of fuel in a diesel engine is dependent upon the （）
单项选择题 Persistent knocking of one cylinder of a diesel engine ceases when the fuel supply to that cylinder is securedThis problem may be a result of （）