BMW X5 Owners & Service Manuals

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.

Engine Diagnosis
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.

READ NEXT:

 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

SEE MORE:

 Engine-Off / Coasting

Principle Under certain conditions the engine is automatically decoupled from the transmission in the D selector lever position. The vehicle continues traveling with the engine idling to reduce consumption. Selector lever position D remains engaged. This driving condition is referred to as coastin

 Removing And Installing Or Replacing Steering Column Switch Cluster

WARNING: Move wheels into straight-ahead position and do not alter this position during the repair work. With steering wheel removed, do not under any circumstances turn/twist fixture for steering column stalk! Necessary preliminary tasks: Disconnect battery negative lead. Remove steering whee

© 2019-2024 Copyright www.bmwx5info.com