单项选择题
Which of the following problems will occur if the needle valve in a fuel injection nozzle sticks in the open position?（）
A.Fuel injection timing will change B.Nozzle operation will be unaffected C.Fuel will leak into the drain line D.Fuel will not be delivered
单项选择题 A dry-type exhaust muffler clogged with soot, will cause（）
单项选择题 An operating turbocharged diesel engine that suddenly loses power, is due to a/an（）
单项选择题 The exhaust valve opens before bottom dead center in a four stroke engine to（） Ⅰ.allow for blow down Ⅱ.Reduce pumping losses
