Isuzu KB P190. Manual - part 242

6C – 4   FUEL SYSTEM 

 
 

FUEL FILTER AND WATER SEPARATOR 

As the inside of the injection pump is lubricated by the fuel which it is pumping, the fuel must be perfectly clean. The 
fuel filter and the water separator remove water particles and other foreign material from the fuel before it reaches 
the injection pump. 
The water separator has an internal float. When the float reaches the specified level, a warning light comes on to 
remind you to drain the water from the water separator. 
A diaphragm type priming pump is installed at the top of the fuel filter. It is used during the air bleeding procedures. 
 

(Except EURO III model) 

 

 

 

 

RTW36CLF000701 

 

FUEL SYSTEM    6C – 5 

 

For EURO III model 

  

 
 
 

 

 

RTW46AMF000201 

6C – 6   FUEL SYSTEM 

INJECTION PUMP 

 

 

 

 

RTW46CLF000201 

 
4JA1T(L): 

A Bosch Distributor Type Injection Pump is used. A single reciprocating/revolving plunger delivers the fuel uniformly 
to the injection nozzles, regardless of the number of cylinders. 
The governor, the injection timer, and the feed pump are all contained in the injection pump housing. The injection 
pump is compact, light weight, and provides reliable high-speed operation. 
The vacuum-type fast idle actuator increases the engine idling speed to provide the additional power required to 
operate the air conditioner. 
Fast idler diaphragm movement is caused by changes in the negative pressure created by the engine’s vacuum 
pump. 
The diaphragm motion is transferred to the injection pump control lever to increase or decrease the idling speed. 
 
4JA1TC/4JH1TC: 

The Bosch VP44 injection pump is electronically controlled. The pump controller combine to injection pump. 
Signals from the pump controller are sent to the engine control module (ECM). In response to these signals, the 
ECM selects the optimum fuel injection timing and volume for the existing driving conditions. 

FUEL SYSTEM    6C – 7 

INJECTION NOZZLE (4JA1L) 

  

 

 

RTW76CMF000301

 

NOTE: 
•  Injection nozzle adjustment is possible only on the 4JA1L engine. 
 
A hole (with 5 orifices) type injection nozzle. It consists of the nozzle body and the needle valve assembly. 
The injection nozzle assembly sprays pressurized fuel from the injection pump into the combustion chamber through 
the nozzle body injection orifice.