The fuel pump is equipped with a boost pressure regulator. The main function of this regulator is to reduce exhaust emissions during acceleration or at low speeds and maximum load. The boost pressure regulator is mounted on the top of the pump. Figure 25.1 shows the design of the turbocharger with the location of its main components.
25.1 Turbocharger device1. Air filter; 2. Intake air compressor; 3. Drive mechanism turbine (turbocharger); 4. Charge air cooling radiator;5. Main air intake pipes;6.Fuel pump with boost pressure regulator; 7. Boost pressure indicator;8. Oil separator (drain to oil pan)
Problems and reasons
a) Loss of power: If the boost pressure is as specified, check that the connecting hose between the intake pipe (5) and the boost pressure regulator (6) is OK. It is also possible that the pump is not delivering enough fuel. Contact a workshop to fix the problem.
b) Black exhaust is due to insufficient boost pressure: check the intake air duct for leaks. Air leaks can occur, for example, at the air filter connection or the charge air cooler. A damaged turbocharger can also be suspect.
c) Black exhaust at normal boost pressure indicates too much fuel is being supplied. Have the pump checked by a workshop.