Checks On Pressure: Dynamic; Abnormal Functioning; Impossible To Start The Engine - CITROEN C5 2005 Service Manual

CHECKS: LOW PRESSURE FUEL SUPPLY CIRCUIT

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.

Fuel supply pressure
Between 3.3 and 4 bar
More than 4 bar
More than 4 bar
Between 0.8 and 1.5 bar

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).
Checks
The flow should be drop by drop
Excessive fuel return
Engine: 4HX
Fuel return pressure
0.8 ± 0.4 bar
Less than 0.8 bar
More than 0.8 bar Check the fuel return circuit (pipe pinched or trapped...)
Less than 0.8 bar
Check: diesel injector return flow (table below).
Uncouple the diesel injector return pipe.
Diesel injector functioning correctly
Diesel injector locked shut
193
Checks
Check the condition of the diesel filter
Check the low pressure regulator incorporated
in the filter (locked shut): replace.
Check the fuel suppy circuit:
- Booster pump (low pressure), piping
Observe
C5