4000S Diesel L4-1588cc 1.6L DSL SOHC (JK) (1983)
Diesel MFI Pump: Description and Operation
Fuel Supply
Fig. 5 Diesel fuel system
Fuel is drawn through the filter from the tank by the injection pump, Fig. 5. The injection pump meters and distributes fuel under pressure to the
injectors in the correct firing order.
Excess fuel from the pump and injectors returns to the tank through a separate line.
The fuel circulation cools and lubricates the injection pump and injectors and also warms the fuel in the tank slightly to help prevent wax formation
during cold weather.