Volkswagen Workshop Service and Repair Manuals

Check fuel flow Check conditions l  The Fuel pump (pre-supply pump) -G6- supply does not display any irregularities. l  Remote control -VAG 1348/3A- l  Residual pressure and fuel pressure regulator in order → Chapter. Checking process   Note The supply flow of the Fuel pump (pre-supply pump) -G6- for BAH engine is measured at 3.0 bar and at 4.2 bar for BPA/CCRA engine. Because of that, fuel pressure must be checked before measuring the flow → Chapter. –  Remove fuel filling nozzle cap. BAH engine

–  Remove return hose -1- from fuel pressure regulator. –  Connect Adapting set -VAG 1318/17- to fuel pressure regulator. –  The end of the Adapting set -VAG 1318/17- should be installed in a 3.0-liter (minimum) graduated container. BPA/CCRA engines

–  Remove outlet hose from fuel filter position -1-.   Note To unfasten fuel lines, press the safety key. –  Connect the Adapting set -VAG 1318/17- to position -1- of fuel filter outlet and to the Pressure gauge -VAG 1318- . –  Install the Pressure gauge -VAG 1318- to the Adapter -VAG 1318/11- and the Adapting set -VAG 1318/16-. –  The end of the Adapting set -VAG 1318/16- should be installed in a 3.0-liter (minimum) graduated container. The procedures below are common for engines. –  Open the Pressure gauge -VAG 1318-valve. The valve points towards the direction of flow -A-. –  Activate the Remote control -VAG 1348/3A- and close the valve slowly until thePressure gauge -VAG 1318- reads a pressure of 3.0 bar (BAH engine) and 4.2 bar (BPA/CCRA engines). Do not change the valve position any more. –  Empty the graduated container. –  The flow of the Fuel pump (pre-supply pump) -G6- depends on the Battery -A-voltage. Accordingly, connect a Multimeter -VAG 1715- to the Battery -A- using a Set of auxiliary measuring cables -VAG 1594C-. –  Activate the Remote control -VAG 1348/3A- for 30 seconds and measure voltage. –  Compare the Fuel pump (pre-supply pump) -G6- voltage and flow found with the theoretical value in the graphic below: If the flow found is the same or higher than the theoretical value, the Fuel pump (pre-supply pump) -G6- is in top condition, as well as the fuel filter, the pipes and the screen filter of the Fuel pump (pre-supply pump) -G6-.

BAH engine 1)  Minimum amount cm3/30 s 2)  Voltage in the Fuel pump (pre-supply pump) -G6- with engine stopped andFuel pump (pre-supply pump) -G6- operating (approx. 2 volts less than Battery -A-voltage). Sample reading: During the test, a voltage of 10.5 volts is measured. With this voltage in the Fuel pump (pre-supply pump) -G6- the result shown is a minimum flow of 540 cm3/30 s.

BPA/CCRA engines 3)  Minimum amount cm3/30 s 4)  Voltage in the Fuel pump (pre-supply pump) -G6- with the engine stopped and the Fuel pump (pre-supply pump) -G6- working (voltage in the Fuel pump (pre-supply pump) -G6- is 2 volts less than that of the Battery -A-). Sample reading: During the test, a voltage of 10.5 volts is measured. With this voltage in the Fuel pump (pre-supply pump) -G6- the result shown is a minimum flow of 583 cm3/30 s. If minimum flow is not reached: –  Check if the supply pipes for the filter present folds or obstructions. If fuel lines are in order. –  Check fuel flow before fuel filter.   WARNING Fuel supply lines are under pressure. Wrap hose connection with cloth prior to loosening. Next, eliminate pressure by disassembling hose carefully. BAH engine

–  Remove the supply hose -1- from the fuel filter inlet and connect it to Adapting set -VAG 1318/17-. –  Attach the Adapting set -VAG 1318/17- with connector -1- to the Pressure gauge -VAG 1318-. –  Connect the Pressure gauge -VAG 1318- to the Adapter -VAG 1318/11- and Adapter set -VAG 1318/1-. –  The end of the Adapting set -VAG 1318/1- should be installed in a 3.0-liter (minimum) graduated container. BPA/CCRA engines

–  Remove the supply hose -1- from the fuel filter inlet and connect it to Adapting set -VAG 1318/17-. –  Attach the Adapting set -VAG 1318/17- with connector -1- to the Pressure gauge -VAG 1318-. –  Connect the Pressure gauge -VAG 1318- to the Adapter -VAG 1318/11- and Adapter set -VAG 1318/16-. –  The end of the Adapting set -VAG 1318/16- should be installed in a 3.0-liter (minimum) graduated container.   Note To unfasten fuel lines, press the safety key. The procedures below are common for engines. –  Open the Pressure gauge -VAG 1318-valve. The valve points towards the direction of flow -A-. –  Activate the Remote control -VAG 1348/3A- and close the valve slowly until the Pressure gauge -VAG 1318- reads a pressure of 3.0 bar (BAH engine) and 4.2 bar (BPA/CCRA engines). Do not change the control valve position any more. –  Empty the graduated container. –  Activate the Remote control -VAG 1348/3A- once more for 30 seconds. Compare the fuel flow with the one obtained in the first measurement. If minimum fuel flow is reached: –  Replace fuel filter. If minimum fuel flow is not reached: –  Remove the Fuel pump (pre-supply pump) -G6- and check whether the screen filter is dirty. Only if no irregularities have been found so far: –  Replace Fuel pump (pre-supply pump) -G6-. If fuel flow is reached, but the fuel supply might present irregularities (for example: a momentary fault in the fuel supply): –  Check current draw of the Fuel pump (pre-supply pump) -G6-, proceeding as follows:

–  Reconnect all fuel hoses removed again. –  Connect the Multimeter -VAG 1715- to harness red/blue cable (pole 1) engine BAH, blue/white (pole 1) engines BPA/CCRA using the current leakage clamp meter -arrow-. –  Start the engine and run it at idle speed. –  Measure current draw by the Fuel pump (pre-supply pump) -G6-. During the test, the maximum current theoretical value is 8.0 ampere for BPA/CCRA engines and 6.5 ampere for BAH engine.   Note If it is an occasional fault in the fuel system, checking can also be carried out during test drive, which is a two-men job. In case of excessive current draw: –  Fuel pump (pre-supply pump) -G6- - damaged, replace it.