🔍 Key Concepts

• jerk-type fuel injection pump operation (how the plunger, helix, and ports work together) • role of the spill/inlet port that is uncovered/covered by the plunger helix • difference between amount of fuel per stroke and simply supplying or lubricating fuel

💭 Think About

• Look at where "G" is located relative to the plunger helix and the control sleeve: when that port is open, what happens to pressure in the pumping chamber? • When the plunger rises and covers/uncovers "G", is it mainly starting injection, ending injection, or just feeding fuel into the pump body? • Which of the answer choices describes a function that depends on opening/closing a side port at that specific height in the barrel?

✅ Before You Answer

• Confirm that "G" is connected to the low‑pressure fuel gallery and is controlled by the plunger helix edge. • Decide whether this port’s opening/closing would change the quantity of fuel delivered during the stroke or simply act as a general supply/lube passage. • Eliminate any options that would normally be handled by a separate relief valve or lubrication system, not by this side port.