Contents: Stage 1, the engine was started on…⬇ Stage 2, the engine was not started…⬇ Stage 3, there are chips in the fuel…⬇ Stage 4, no chips in fuel delivery…⬇ Stage 5, there are metal shavings in…⬇ Stage 6, no chips in the fuel…⬇
Note: The fuel lines are connected with quick-release couplings. Fuel hoses may only be secured with spring clamps. It is recommended to use clamp pliers to install spring clamps. Observe safety regulations. Observe cleanliness regulations. Diesel fuel has lubricating properties, so filling with unsuitable fuel (not diesel) may lead to significant (beyond repair) damage to components of the high-pressure system. This is especially true for the high-pressure fuel pump. In this case, damage in the form of scoring and the formation of wear particles can be expected. Free metal particles contaminate the fuel system and injectors, which inevitably results in other damage, primarily in the fuel pressure regulator and injectors.
Note: These instructions should be followed in accordance with the flow chart, taking into account the different conditions when carrying out some work.
Did the engine start after refueling with the wrong fuel?
- Yes - "Stage 1, the engine was started on the wrong fuel."
- No - "Stage 2, the engine was not started on the wrong fuel."
Stage 1, the engine was started on the wrong fuel
Pump out as much fuel as possible from the tank through the filler pipe using the fuel pumping device "VAS 5190". Remove the rear seat. Unlock the latches of the cover "1" of the connecting flange using the wedge "3409" "arrows".
Remove the sealing sleeve "1" from the cover "2" with a downward movement. Move the cover "2" back along the wiring harness "3".
Attention! It should be noted that if the battery is connected, the fuel pump turns on when the door is opened. Fuel may leak from the open system.
Disconnect the fuel return line "2" on the connecting flange. Unlock and disconnect the quick-release coupling. Connect the connecting hose "VAS 6551/1" pressure gauge to the fuel return line. If necessary, extend the connecting hose "VAS 6551/1" using a connecting tip "VAS 6551/5" 1- and standard hose to the pipeline. Bring the free end of the pipeline/connecting hose "VAS 6551/1" into a suitable container. Connect the tester to the vehicle. Perform Emptying the fuel tank in Guided Functions mode.
Note: The fuel pump is switched on.
Repeat this process until there is no fuel left in the fuel tank. Remove the fuel delivery module. Check the fuel tank for chips. Drain the fuel from the fuel delivery module storage tank. Inspect the storage tank and pre-filter for coarse dirt and chips.
Do you have any shavings?
- Yes - "Stage 3, there are chips in the fuel delivery module and fuel tank."
- No - "Stage 4, no chips in fuel delivery module and fuel tank."
Stage 2, the engine was not started on the wrong fuel
Pump out as much fuel as possible from the tank through the filler pipe using the fuel pumping device "VAS 5190". Remove the rear seat. Unlock the latches of the cover "1" of the connecting flange using the wedge "3409" "arrows". Remove the sealing sleeve "1" from the cover "2" by moving it downwards. Move the cover "2" back along the wiring harness "3".
Attention! It should be noted that if the battery is connected, the fuel pump turns on when the door is opened. Fuel may leak from the open system.
Disconnect the return fuel line "2" on the connecting flange. Unlock and disconnect the quick-release coupling. Connect the connecting hose "VAS 6551/1" pressure gauge to the fuel return line. If necessary, extend the connecting hose "VAS 6551/1" using a connecting tip "VAS 6551/5" 1- and standard hose to the pipeline. Bring the free end of the pipeline/connecting hose "VAS 6551/1" into a suitable container, Connect the tester to the vehicle, Perform Emptying the fuel tank in Guided functions mode.
Note: The fuel pump is switched on.
Repeat this process until there is no fuel left in the fuel tank. Fill the fuel tank with 5 liters of diesel fuel. Completely empty the fuel tank again as described above. Reconnect the fuel return line "2". Replace the fuel filter. Completely fill the car and test drive.
Stage 3, there are chips in the fuel delivery module and fuel tank
Clean the fuel delivery module and fuel tank using a device such as "VAS 5226". Install the fuel delivery module.
Car with independent heater
Check the fuel line between the fuel tank and the metering pump -V54- for chips. Replace if necessary.
All
Fill the fuel tank with 5 liters of diesel fuel. Drain the fuel tank completely again as described above. Replace the following components of the high-pressure fuel system: injection pump, high-pressure fuel lines, fuel rail including fuel pressure regulator "N₂76" and fuel pressure sensor "G247", injectors, fuel return lines (fuel drain lines), fuel filter. Fill the car completely. Remove air from the fuel system. Perform a test drive.
Stage 4, no chips in fuel delivery module and fuel tank
Fill the fuel tank with 5 litres of diesel fuel. Empty the fuel tank again completely as described above.
Caution! When removing the fuel metering valves from the high-pressure pump, there is a risk of dirt getting into the pump, which will lead to pump failure. For this reason, before removing, it is necessary to thoroughly clean the fuel metering valves and the high-pressure pump, observing the rules for maintaining cleanliness when working with the injection system.
Disconnect the connector from the valve. Unscrew the "arrow" screws and carefully remove the fuel metering valve "N₂90" -A- from the high-pressure pump. Check the fuel metering valve "N₂90" and the high-pressure fuel pump for chips.
Do you have any shavings?
- Yes - "Stage 5, there are metal shavings in the fuel injection pump."
- No - "Stage 6, no chips in the fuel injection pump."
Stage 5, there are metal shavings in the fuel injection pump
Replace the following components of the high-pressure fuel system: injection pump, high-pressure fuel lines, fuel rail, including fuel pressure regulator "N₂76" and fuel pressure sensor "G247", injectors, fuel return lines (fuel drain lines), fuel filter. Fill the car completely. Remove air from the fuel system. Perform a test drive.
Stage 6, no chips in the fuel injection pump
Attention! Avoid damaging the sealing rings of the fuel metering valve "N₂90". If the sealing ring is damaged, the high-pressure fuel pump must be replaced.
Lubricate the lower sealing ring of the fuel metering valve "N₂90" with fuel. Insert the valve into the high-pressure fuel pump, turning it slightly. Screw in the screws "see arrows" only by hand. Pre-tighten the screws with a torque of 3 Nm, then tighten with a torque of 7 Nm. Replace the fuel filter. Bleed air from the fuel system. Fill the car completely and perform a test drive.