Engine 2014: Motor Plants and Auxiliary Boilers

1. A prevent carbon deposits from forming on the injector nozzle
2. B help the injector needle reseat without dribbling at the nozzle holes
3. C maintain popping pressure in the high pressure steel piping to the injector
4. D ensure a fuel leak off between the plunger and barrel which  provides lubrication for relative movement

Tip: press A-D to answer