1900006040 TOYOTA PUMP ASSY, INJECTI Calibration Data

The fuel system consists of the injection pump assembly (injection pump proper, governor, feed pump, automatic timer), injection nozzle, fuel filter, fuel tank, and other parts.Fuel is fed from the fuel tank through suction hose to the feed pump of the injection pump assembly, and then to the fuel filter, injection pump, and injection nozzle. The excess fuel is returned from the injection nozzle and injection pump to fuel tank.The driving method of the injection pump differs between unit with and without compressor as shown below. When the unit is with an air compressor, the drive gear of the air compressor is driven by the timing gear and between the air compressor crankshaft and autotimer, drive is made by the driving disc. In the case of unit without air compressor, there are two types; the drive gear in the pump drive case is driven by the timing gear and between the coupling in the pump drive case and the auto timer, drive is made by the driving disc; the injection pump drive gear is directly driven by the timing gear.Refer to Group 12 Lubrication for lubrication of the injection pump.(1) Injection Pump Proper Bosch A or AD type injection pump is adopted. The construction of the injection pump is as shown. The injection pump is a device which forces fuel to the injection nozzle and has a mechanism for increasing or decreasing the pressure feed quantity according to the engine load and speed.It has one plunger and delivery valve for each cylinder.The plunger, pushed up by the camshaft and pushed back by the plunger spring, moves up and down through the plunger barrel on a predetermined stroke to feed fuel under pressure.The plunger also controls the injection amount by adjusting the suction/discharge port opening timing. The camshaft is supported by two taper roller bearings and a center bearing. It has two types of cams to operate the actuators and to operate the feed pump-and is driven by the pump drive gear at 1/2 engine speed.(a) Pressure feed of fuel The plunger has an obliquely cut groove (lead) on its side as shown. At the top of the plunger there is a hole which leads to the groove. The plunger barrel has suction/discharge port.The fuel delivered to the injection pump is forced by the rotation of the camshaft or reciprocating motion of the plunger as shown above.When the plunger is at the lowest position or bottom dead center (a), fuel flows through the suction/discharge port into the plunger.Rotation of the camshaft moves the plunger up. When the top surface of the plunger is lined up with the suction/discharge port, application of pressure to fuel begins (b).As the plunger moves up further (c), and the lead of the plunger meets with the suction/discharge port, the high pressure fuel flows through the hole in the plunger and runs back from the lead to the suction/discharge port, and the pressure feed of fuel is completed (d).The plunger stroke during which the fuel