Entire System Pressure Test
- Fuel delivery rate and pressure test in the fuel supply is OK.
- The Diesel Pressure Tester Kit - Adapter Set - Connection Hose 2 VAS 6551/5-2 must be connected to the fuel supply line and the Diesel Pressure Tester Kit VAS 6551.
- Vehicle Diagnostic Tester is connected.
-- Connect the Diesel Pressure Tester Kit - Adapter Set - Adapter 1 VAS 6551/5-1 to the fuel supply hose -1- to the high pressure pump, secure it with a hose clamp and install the Diesel Pressure Tester Kit - Hose 2 VAS 6551/2.
-- Connect the Diesel Pressure Tester Kit - Hose 2 VAS 6551/2 to the Diesel Pressure Tester Kit VAS 6551.
The Diesel Pressure Tester Kit VAS 6551 is inserted in the fuel supply line.
-- Switch on the Diesel Pressure Tester Kit VAS 6551 -1- by pressing the On/Off button.
-- Open the shut-off valves -A and B-.
- The levers point in the direction of flow.
Risk of fuel leak.
- The shut-off valve -C- must be closed.
- The lever is perpendicular to the direction of flow.
-- Turn on the ignition and select the following menu items on the Vehicle Diagnostic Tester:
- OBD
- Engine Electronics
- Basic Setting
- Transfer Fuel Pump Test
-- Press Start : The fuel pump starts.
-- Read the fuel pressure in the Diesel Pressure Tester Kit VAS 6551.
- Specified value: 3.8 to 5 bar (55 to 84.1 psi)
If Specified Value Is Not Reached, Although the Fuel Delivery Rate Was OK:
- The high pressure pump overflow valve is not OK
If the Specified Value Is Exceeded By More Than 6 bar (87 psi)
- The fuel return line is blocked or kinked.
Assembling
Assembly is performed in the reverse order of disassembly, noting the following:
- The ignition must be off.
Decrease the fuel pressure by opening the drains -B and C- and letting the fuel run into the measuring container before removing the pressure gauge -1-.
-- Remove the Diesel Pressure Tester Kit VAS 6551 with the connecting cables.
-- Secure the fuel supply line with a hose clamp and then pull on it to make sure the fuel supply line is secure.