Full pump
The Isuzu 6-ton diesel fuel pump is an inline pump type commonly branded as Bosch P or Zexel. The number of plungers in this pump equals the number of engine cylinders which is four. The plunger diameter in this pump varies between 8 to 10 millimeters depending on the engine model. The maximum generated pressure by this pump reaches 700 to 1200 bars. The nominal pump speed at full engine RPM between 3000 to 3500 is precisely calibrated. The pump housing is manufactured from ductile cast iron with thermal stress relief treatment. The internal rotor and vanes of the feed pump are made of hardened steel reaching 55 HRC. The lubrication system of this pump operates automatically using engine oil or diesel fuel. The clearance between plunger and barrel cylinder is less than 2 microns for minimal internal leakage. The pump weighs approximately 15 to 20 kilograms depending on the exact model configuration.
This pump is installed on 4JB1, 4JH1, and 4HG1 diesel engines found in Isuzu 6-ton trucks. The injection timing for the 4JB1 engine is set between 8 to 10 degrees before top dead center. The fuel delivery amount per cycle is adjusted using calibration screws located on the pump head. The tightening torque for pump mounting bolts to the engine block is between 25 to 35 Newton-meters
