Fuel Injection Pump
The injection pump is driven by a belt at the front of the engine. If draws fuel from the tank, pressurizes it, and injects a specific quantity to each cylinder at the proper time. Excess fuel is returned to the tank through another line. The injection pump is not serviceable and should not be disassembled.
NOTE:
Air conditioned vehicles have a vacuum unit that increases idle speed when the air conditioning is on.