单项选择题
A.formation of carbon on the intake and exhaust ports
B.high water jacket temperatures
C.overheated pistons and cylinders
D.an increase in lube oil viscosity due to fuel dilution
单项选择题 In a turbocharged four-stroke/cycle diesel engine, the exhaust valve remains open until after top dead center and the intake valve opens before top dead center to（）.
单项选择题 Early injection timing is indicated by （）.
单项选择题 A faulty injection in one cylinder of an operating diesel engine can be located by （）