Workshop Hints
Workshop HintsBefore any service work is performed on any fuel system related component, always adhere to the following:
^ Observe relevant safety legislation pertaining to your area.
^ Ensure adequate ventilation.
^ Use exhaust extraction system where applicable (alleviate fumes).
^ DO NOT OPERATE THE FUEL PUMP unless it is properly installed in the fuel tank and is submersed in the fuel Duel lubricates the pump).
^ Always wear adequate protection clothing including eye protection.
^ Use caution when working around a hot engine compartment
^ During fuel system repair that involves sealing rings, always replace them with a new COPPER rings only.
^ BMW does not recommend any UNAUTHORIZED MODIFICATIONS to the fuel system. The fuel system are designed to comply with strict federal safety and emissions regulations. In the concern of product liability, it is unauthorized to sell or perform modifications to customers vehicles, particular in safety related areas.
^ Always consult the Repair Instructions on the specific model you are working on before attempting a repair.
Fuel
Fuel quality should always be considered when diagnosing a driveability complaint. The type of fuel, proper AKI rating, impurities and moisture are not factored by the ECM.
Please refer to the Owners Manual and following Service Information Bulletins regarding fuel:
^ Gasoline Fuel Quality S.l. #13 01 88 (1564)
^ Gasoline Additive S.l. #13 04 88 (1591)
Fuel Supply
The fuel supply hardware should be visually inspected for damage that can affect pickup, transfer, pressure and return. Please refer to the Repair Instructions for details on fuel supply hardware.
Fuel Filter, Pressure Regulator, Pump and Sending Unit Access
Caution: The fuel tank must be drained first before removing the Service access cap to perform any repair attempts.
Consult the Repair Instructions for additional details and updated information.
1. Fuel tank
2. Service access cap
The fuel filter, fuel pressure regulator, electric fuel pump, right fuel level sensor and syphon jet are accessed through the "Service access cap". Remove the single 6 pin electrical connector (2 pins for the fuel pump, 2 for each level sensor left/right). Remove the fuel supply line by releasing the quick release coupling.
The fuel tank is secured by two straps to the body.
The Fuel Injectors should also be tested using the DlSplus/GT1 for:
^ Resistance
^ Power Supply
^ Status Display Fuel Injection Signal
^ ECM Final Stage transistor activation. This test functions is found under the oscilloscope Preset list "Ti Injection Signal". Install the Universal Adapters Diagnostic cable MFK 2 negative lead to ECM ground and MFK 2 positive lead to the ground activation circuit for the injector. This test is performed with the engine cranking or running.
Crankshaft Position/RPM Sensor
This sensor should be tested using the DlSplus/GT1 for:
^ Power Supply
^ DC Voltage
^ Status Display
^ Oscilloscope Display found under Preset Measurements Engine Speed Sensor Signal
Engine Coolant Temperature
NTC sensors decrease in resistance as the temperature rises and vice versa. The ECM monitors the sensor voltage which varies as temperature changes the resistance value. For example, as temperature rises:
^ Resistance through the sensor decreases
^ Voltage drop of the sensor decreases
^ Input signal voltage also decreases (5Ov)
The Sensor should be tested using:
^ DISplus/GT1 Multimeter degrees C (dependent on engine temperature).
^ DISplus/GT1 Multimeter ECM input 2.250K ohms at 20° C Temp. Gauge input 6.7 k ohms at 20° C Temperature. Gauge input 6.7 K ohms at 20° C.
Fuel
Fuel quality should always be considered when diagnosing a driveability complaint. The type of fuel, proper AKI rating, impurities and moisture are not factored by the ECM.
Please refer to the Owners Manual and following Service Information Bulletins regarding fuel:
^ Gasoline Fuel Quality S.l. #13 01 88 (1564)
^ Gasoline Additive S.l. #13 04 88 (1591)
Fuel Supply
The fuel supply hardware should be visually inspected for damage that can affect pickup, transfer, pressure and return.
Fuel Filter, Pressure Regulator, Pump and Sending Unit Access
Caution: The fuel tank must be drained first before removing the Service access cap to perform any repair attempts.
Consult the Repair Instructions for additional details and updated information.
1. Fuel tank
2. Service access cap.
The fuel filter, fuel pressure regulator, electric fuel pump, right fuel level sensor and syphon jet are accessed through the "Service access cap". Remove the single 6 pin electrical connector (2 pins for the fuel pump, 2 for each level sensor left/right). Remove the fuel supply line by releasing the quick release coupling.
The fuel tank is secured by two straps to the body.
The Fuel Injectors should also be tested using the DlSplus/GT1 for:
^ Resistance
^ Power Supply
^ Status Display Fuel Injection Signal
^ ECM Final Stage transistor activation. This test functions is found under the oscilloscope Preset list "Ti Injection Signal". Install the Universal Adapters Diagnostic cable MFK 2 negative lead to ECM ground and MFK 2 positive lead to the ground activation circuit for the injector. This test is performed with the engine cranking or running.
Crankshaft Position/RPM Sensor
This sensor should be tested using the DlSplus/GT1 for:
^ Power Supply
^ DC Voltage
^ Status Display
^ Oscilloscope Display found under Preset Measurements Engine Speed Sensor Signal
Engine Coolant Temperature
NTC sensors decrease in resistance as the temperature rises and vice versa. The ECM monitors the sensor voltage which varies as temperature changes the resistance value. For example, as temperature rises:
^ Resistance through the sensor decreases
^ Voltage drop of the sensor decreases
^ Input signal voltage also decreases (5Ov)
The Sensor should be tested using:
^ DISplus/GT1 Multimeter degrees C (dependent on engine temperature).
^ DISplus/GT1 Multimeter ECM input 2.250K ohms at 20° C Temp. Gauge input 6.7 k ohms at 20° C Temperature. Gauge input 6.7 K ohms at 20° C.