Fuel Pressure Test

Fuel Pressure Test

Special tools, testers and auxiliary items required

• Multimeter.

• fuel line adapter set (V.A.G. 1318/17A). These tools may be substituted with an equivalent aftermarket tool and are also available for rental or purchase through Volkswagen.

• In line Fuel pressure gauge with shutoff valve. (high pressure).

Test conditions

• Battery voltage 12.5 V

• Function and voltage supply for the Fuel Pump is OK.

• Fuel tank at least 1/4 filled.

• Ignition switched OFF.

Test procedure

- Observe safety precautions. Refer to => [ Safety Precautions ] Safety Precautions

- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.

Fuel supply line is under high pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before removing from hose connection consult the Repair Information for proper procedure.

- Remove high pressure in fuel system.

- Place a cloth around connection and slowly loosen union nut - arrow - to reduce fuel pressure.





- Then tighten threaded connection again.

- Connect a pressure gauge with the appropriate adapter, as shown.

- Make sure hose clamps are seated securely.





- Open shut off valve of pressure gauge. The lever points in the direction of flow.

- Turn the ignition switch ON for 5 seconds, then off for 10 seconds and repeat 4 times to build maximum pressure from the fuel transfer pump.

- Switch ignition Off.

Fuel pressure must increase up to a maximum pressure of 6 bar.

• When releasing control button of the hand held remote starter (jumper), fuel pressure decreases to approx. 5.6 bar.

If fuel pressure is OK, perform a Residual Pressure check.

If specification is exceeded:

- Pressure relief valve in flange assembly is faulty, replace sender assembly. Refer to the Repair Information.

If specification is not obtained:

- Check fuel lines for possible restrictions (kinks) or blockages.

- Check all fuel lines in fuel tank for leaks.

- Check fuel filter for leaks.

If no malfunction can be found:

- Replace flange assembly with pressure relief valve. Refer to the Repair Information.

- Repeat test.

If fuel pressure is not obtained again:

- Fuel Pump faulty, replace fuel delivery unit. Refer to the Repair Information.