Cooper S (R53) L4-1.6L SC (W11) (2004)
Fuel Pressure: Flow of Diagnosis
Notes on fuel pressure check (reference pressure: environment)
Feature of this version with ambient pressure:
The connection for the vacuum hose of the fuel pressure regulator is located between the throttle and the air cleaner or on the air cleaner.
Test precondition:
The correct fuel pressure regulator is fitted.
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Check whether the fuel pressure regulator suitable for the car is fitted (Correct part number).
Connect test adapter.
Description of operation:
The control function of the fuel pressure regulator must be guaranteed under all operating conditions. The fuel pump must always be able to generate a
higher fuel pressure than the pressure regulated by the pressure regulator.
The injection rate is adjusted by means of the injection time; the injection time is controlled by the EMS2000.
Description of operation: fuel return line
When the engine is at a standstill and the ignition key is in position 0, the fuel return line after the pressure regulator is at zero pressure.
Description of operation: pressure retaining function
The pressure regulator closes when the engine is at a standstill and the ignition key is in position 0. The fuel pressure in the delivery line is retained over
an extended period. A non-return valve closes in the fuel pump. These measures help to retain the fuel pressure in the fuel system. Extended starting
times are thus avoided.
Complaint: drive characteristic faults, lack of power
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Run engine at idle speed and measure fuel pressure.
If the measured value is less than the nominal value - 0.2 bar:
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Line cross-sections in fuel feed are constricted or fuel filter is clogged, or
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Fuel pump voltage supply is not O.K.: e.g. as a result of high contact resistance (corrosion) in plug connection between wiring harness and fuel
pump.
If the measured value is greater than the nominal value + 0.2 bar:
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Turn off engine stop and then observe measured value.
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If measured value drops to nominal value, then line cross-sections in fuel return are constricted or clogged.
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Check the fuel lines for kinks.
If no kinks are visible:
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Replace return lines
If measured value remains too high, then pressure regulator is in all probability faulty.
Important:
With less likelihood, the return line may be completely blocked. When the pressure regulator is removed, fuel could escape under pressure!
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Have a cleaning cloth ready and catch and dispose of escaping fuel.
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Replace the return line but not the pressure regulator.
Complaint: starting problems
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Run engine briefly at idle speed and switch off.
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Note down measured value while engine is stopped.
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Read off measured value again after approx. 20 to 30 minutes while engine is stopped
Special tool 13 3 010 (hose clamp) is required for the following test.
If the measured value has dropped by more than 0.5 bar:
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Start engine and wait briefly for a stable pressure increase.
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Switch off the engine and immediately pinch off the delivery line just before the pressure gauge with the special tool 13 3 010.