Before Opening High Pressure Fuel Injection System
Before Opening High Pressure Fuel Injection System
• The fuel injection system is separated into a high-pressure section (max. approximately 110 bar) and a low-pressure section (approximately 6 bar).
• Before opening the high-pressure section - for example removing the high-pressure pump, fuel rail, fuel injectors, the motor for intake manifold runner control valve or any other component or fuel line that is located in the high-pressure section of the fuel injection system - the fuel pressure in the high-pressure section must be relieved to a residual pressure of approximately 8 bar. The procedure for this is as follows.
Special tools, testers and auxiliary items required
• Vehicle Diagnostic, Testing and Information System ( VAS 5051B) with Diagnostic Cable (VAS 5051/5A )
Procedure
- Start engine and run at idle speed.
- Connect (VAS 5051B) with (VAS 5051/5A ).
Display on (VAS 5051B):
- Click on the Vehicle Self-Diagnosis button.
Display on (VAS 5051B):
- In selection - 1 -, press vehicle system " 01 - Engine electronics".
- Wait until next display appears.
Display on (VAS 5051B):
1 Control module identification of Engine Control Module (ECM)
- Click on -> button.
Display on (VAS 5051B):
1 Selection of diagnostic functions
- In selection - 1 -, press diagnostic function " 04- Basic Setting".
Display on (VAS 5051B):
- Select "140" in button field - 2 - for " display group 140" and confirm the input by pressing the Q button.
Display on (VAS 5051B):
Example:
1. 42%
2. 39.76 bar
3. 40.63 bar
4. Inactive
- Activate basic setting by pressing button A.
Display on (VAS 5051B):
Example:
1. 0%
2. 0 bar
3. 5.46 bar
4. Lower
The fuel rail will continue to be filled with fuel, but it will no longer be under high pressure.
Now components or lines can be opened. A clean rag must be placed around the connection points. Escaping fuel must be absorbed.
- In operating mode Guided Fault-Finding, generate the readiness code for ECM.