Volkswagen Workshop Service and Repair Manuals

Checking sequence –  Remove the fuse support front cover.

–  Remove fuse 41 from the (Fuel pump (pre-supply pump) -G6-) fuse holder.   WARNING Fuel system under pressure! Before opening the system, place a cloth around the connection. Then, release pressure by carefully loosening the connection.

–  Disconnect the supply hose coupling -1- (black or with black marking) and collect the fuel with a cloth.   Note To unlock the fuel hoses, press the safety ring inwards.

–  Connect Pressure gauge -VAG 1318 - with dapter -1318/9- and adapter -1318/17-, as shown. –  Open the Pressure gauge -VAG 1318- valve. The key shows the direction of flow. –  Return fuse 41 (Fuel pump (pre-supply pump) -G6-) to the fuse holder. –  Run the engine and keep it in idle speed. –  Measure the fuel pressure. Theoretical value: approx. 2.8 bar for BBX engine and 3.8 bar for CFEA engine.

–  Disconnect vacuum hose -1- from fuel pressure regulator -2-. Fuel pressure should rise to approx. 3.0 bar for BBX engine and 4.2 bar for CFEA engine. If the theoretical value is not reached: –  Turn the ignition off. –  Check flow of the Fuel pump (pre-supply pump) -G6- → Chapter. If the theoretical value is reached: –  Turn the ignition off. –  Now check tightness and residual pressure. To do so, check the pressure drop on the Pressure gauge -VAG 1318-. After 10 minutes, they must still be at 2.5 bar at least. If residual pressure drops below 2.5 bar: –  Run the engine and keep it in idle speed.

–  Switch ignition off after the pressure has built up. At the same time, the Pressure gauge -VAG 1318- valve shall be closed (valve in the transversal position in relation to the fuel flow direction -arrow-). –  Check pressure drop on the Pressure gauge -VAG 1318-. If the pressure drops: –  Verify the Fuel pump (pre-supply pump) -G6- non-return valve → Chapter. If the pressure does not drop:

–  Open the Pressure gauge -VAG 1318- valve (valve in parallel position to fuel flow). –  Run the engine and keep it in idle speed. –  Switch ignition off after the pressure has built up. At the same time, clamp the return hose. If the pressure does not drop: –  Replace the fuel pressure regulator. If the pressure drops again: –  Check the tightness of the Pressure gauge -VAG 1318-. –  Check the tightness of the hoses and tubes connections, the sealing rings on the fuel distributor, and the injection valves.   Note Before removing the Pressure gauge -VAG 1318-, place a cloth around the connection points to be disconnected, and remove fuse 41 (Fuel pump (pre-supply pump) -G6-) from the fuse holder.