Question 177Motor Plants - QMED

The correct answer is D) varies the quantity of fuel delivered. In a fuel injection system using individual plunger-type pumps, the movement of the pump control rack changes the position of the plunger within the pump cylinder. This directly affects the amount of fuel that is drawn into the pump during the intake stroke and subsequently delivered during the compression stroke. By varying the position of the pump control rack, the quantity of fuel delivered to the engine can be adjusted, which is the primary function of the fuel injection system. The other answer choices are incorrect because they do not accurately describe the effect of the pump control rack movement. Options A and C are unrelated to the pump control rack, while option B describes a change in the pump stroke length, which is not the primary function of the pump control rack.