BMW X5: Fuel Volume Testing
Some driveability concerns are related to incorrect fuel volume. Vehicles with lack of power complaints and mixture related fault codes may have insufficient fuel volume supplied to the fuel injection system. These vehicles may actually pass a fuel pressure test.
Fuel volume issues can be caused by faulty fuel pumps, fuel pressure regulators, clogged or restricted fuel filters and/or fuel lines.
If these driveability concerns are present, then a fuel volume test should be performed. A fuel volume test measures the amount of fuel delivered in a specific time frame.
The fuel pump is activated during this test using the proper test leads to ensure no arcing sparks are present. The fuel feed line is directed to a non-breakable (fuel-proof plastic) measuring can that has graduations for measurement.
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Fig. 15: Checking Fuel Volume Using Measuring Can
A general specification for fuel volume would be approximately one liter in 30 seconds.
Residual Pressure
Fuel injection systems require a residual pressure to present after the engine is switched off. This allows the engine to start immediately after the vehicle has been parked.
If the residual fuel pressure diminishes after the vehicle has been shut off. Upon restart, there will be an extended cranking period before engine start. This is due to the fuel pump attempting to supply enough fuel for startup.
When the fuel system is at rest, there a three components which allow the fuel system to retain sufficient residual pressure. These items are, the fuel pump check valve, the fuel pressure regulator and the fuel injectors.
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Fuel System - E32 With M60
Fig. 16: Identifying Fuel System - E32 With M60 Components
If any of these items are leaking and fail to hold pressure in the fuel rail,
the vehicle will be difficult to start.
The cranking time wi
Engine Adaptation Values
Engine adaptation values can be broken down into two categories:
Additive Mixture Adaptation - additive adaptation refers to "long term
fuel trim". These adaptation are
made by the ECM (DME) at i
Smooth Running Measurement
The DISplus/GT-1 are helpful in pinpointing the cause of an engine misfire.
Once the short test is completed,
the fault memory of the ECM can be read out to determine which cylinder or
cylinders hav
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Removing And Installing/Replacing Switch For Unlocking Glovebox
Necessary preliminary tasks:
Remove decorative strip from middle fresh-air grille.
Unlock catches (1).
Press switch (2) out of decorative strip.
Fig. 212: Pressing Switch Out Of Decorative Strip
REMOVING AND INSTALLING OR REPLACING GRIP TRIM FOR GEAR SELECTOR
SWITCH
Special tools required:
64
Chassis components, Two-axle self-leveling
suspension
Chassis components
The chassis components are optimized for the
vehicle and its application range and thereby ensure
the best possible Driving Dynamics.
Two-axle self-leveling suspension
Principle
Air suspension ensures best possible driving
comfort under all load conditions. Due to a variable
adjus
