193
INJECTION
CHECKS: LOW PRESSURE FUEL SUPPLY CIRCUIT
Engine: 4HX
Checks on pressure: dynamic.
Engine running, at idle (normal functioning):
- Fuel supply pressure shown by the pressure gauge [3] = 2 ± 0.4 bar.
- Fuel return pressure shown by the pressure gauge [3] = 0.8 ± 0.4 bar.
Abnormal functioning.
Impossible to start the engine:
Fuel supply pressure less than 0.8 bar:
- Check the low pressure regulator incorporated in the filter (locked open).
- Check the high pressure pump distribution valve (locked shut).
Check: diesel injector return flow (table below).
Uncouple the diesel injector return pipe.
Fuel supply pressure Fuel return pressure Checks
Between 3.3 and 4 bar 0.8 ± 0.4 bar Check the condition of the diesel filter
More than 4 bar
More than 4 bar
Less than 0.8 bar
More than 0.8 bar
Check the low pressure regulator incorporated
in the filter (locked shut): replace.
Check the fuel return circuit (pipe pinched or trapped…)
Between 0.8 and 1.5 bar Less than 0.8 bar
Check the fuel suppy circuit:
- Booster pump (low pressure), piping
Checks
Observe
The flow should be drop by drop
Diesel injector functioning correctly
Excessive fuel return
Diesel injector locked shut
C5
Angl.T3-page191-206-2005 4/02/05 15:05 Page 193
To Next Page
Loading...
