BMW X5: Fuel System - E32 With M60
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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 will be excessive and possibly not start at all. For example, If the fuel injectors are leaking, the vehicle will exhibit black smoke on startup.
Diagnosis of these concerns requires a fuel pressure gauge. The residual pressure is monitored on the fuel pressure gauge when the engine is shutoff. Diagnosis is determined by watching the drop in fuel pressure over time. The fuel pressure should not drop more than.5 bar in 30 minutes. If the pressure drops more than.5 bar, the concern should be investigated.
Fuel System - E39/E46 with M54
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Fig. 17: Identifying Fuel System - E39/E46 With M54 System Diagram
Depending on the type of fuel system used, diagnosis will vary. On older fuel systems, diagnosis is simplified due to the ability to clamp off certain components to determine, the origin of the leakdown.
Fuel System - E60
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Fig. 18: Identifying Fuel System - E60 Components
Newer fuel system use a non-return type fuel system with some components mounted externally. Most recently, many of the new vehicle have most of the fuel system components mounted in the fuel tank. This includes the fuel pump, fuel filter and fuel pressure regulator. The only fuel system component outside the fuel tank is the fuel feed line, fuel rail and fuel injectors.
This makes the diagnosis of residual pressure concerns more difficult. Diagnosis of this type of system sometimes requires process of elimination.
If one or more of the fuel injectors is suspected as the cause of the loss in residual fuel pressure. They can be tested using a special tool to "bubble test" the injectors.
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Fig. 19: Testing Bubbles In Injectors Using Special Tool
First the injectors are connected to the test fuel rail supplied with the tool. Then, the fuel injectors are subjected to compressed air. The injectors are then triggered by the test harness to "blow out" any residual fuel.
The test harness is disconnected and the tips of the injectors are immersed in water. The injector tips are observed for any bubbles over time. Any excessive bubbles indicate a defective injector.
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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
SEE MORE:
Injection Nozzle And Lines
REPLACING COMPLETE INJECTION PIPE (N52/ N52K)
Special tools required:
13 5 281
Necessary preliminary tasks:
Read out fault memory of DME control unit
Switch off ignition
Remove clean air pipe
Remove ignition coil cover
Recycling
Fuel escapes when fuel line is detached. Catch and dispose of
Replacing Engine Carrier With Wheel Arch, Left
Read contents of Body, General.
The steel-aluminum mixed construction is used on the vehicle.
Observe specific procedure.
Remove or cover those vehicle components in the repair area which are
susceptible to heat or dust.
Use only approved spot-welding apparatus for repairs.
Place vehicle on st
