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INJECTION
CHECKS : LOW PRESSURE FUEL SUPPLY CIRCUIT
Engines : RHY - RHZ - 4HX (continued)
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 et 4 Bars 0.8 ± 0.4 Bar Check the condition of the diesel filter
More than 4 Bars
More than 4 Bars
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 et 1.5 Bar Less than 0.8 Bar
Check the fuel suppy circuit :
- Booster pump (low pressure), piping.
Check :
Observe :
The flow should be drop by drop
Diesel injector functioning correctly
Excessive fuel return
Diesel injector locked shut.
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