Checking delivery rate

WARNING: This page is about a different variant/trim than selected.

Conditions

Voltage supply OK
Remote control VAG 1348/3 A is connected

Work sequence

Remove cover from fuel filler neck.

Fig 1: Identifying Vacuum Hose To Throttle Valve Control Module, Fuel Return Hose & Fuel Supply Hose

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Remove feed line - 3 - and use a clean rag to catch fuel flowing out.

NOTE:

Press the tabs on the hose couplings together to disconnect.

CAUTION: The feed line is under pressure! Place clean rags around the hose connections, then reduce the pressure by disconnecting the hose very slowly and carefully.

Fig 2: Pressure Gauge V.A.G 1318 Connections

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Connect K-Jetronic pressure tester VAG 1318 with Connector VAG 1318/23 , and connect Adapter set VAG 1318/17 to feed line.
Place Adapter VAG 1318/1 hose on pressure meter Adapter VAG 1318/11 and hold it in a measuring vessel.
Open pressure meter shut-off valve. Lever will then be pointing in direction of flow - A -.
Actuate Remote control VAG 1348/3 A. Simultaneously, close shut-off valve slowly until manometer reads 3 bars of positive pressure. Do not change shut-off valve setting again.

Empty measuring vessel.
Fuel pump capacity depends on battery voltage. Therefore connect multimeter to battery using auxiliary cables from Auxiliary measuring tool set VAG 1594 A.
Actuate remote control for 30 seconds and measure battery voltage simultaneously.

Fig 3: Fuel Delivery Rate Graph

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Compare fuel flow with specification.

*) Minimum delivery cm ³ /30 s

**) Voltage at fuel pump when motor is off but pump is running (approx. 2 volts less than battery voltage).

Example:

During the test, the voltage of the battery was measured as 12.5 volts. Since the pump voltage is approximately 2 volts lower than that of the battery, a minimum delivery of 200 cm ³ /30 s results.

If the minimum delivery rate is not achieved:

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

Fig 4: Pressure Gauge V.A.G 1318 Connections (2 Of 2)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Disconnect feed hose - 1 - from fuel filter inlet.

NOTE:

Press the tabs on the hose couplings together to disconnect.

CAUTION: The feed line is under pressure! Place clean rags around the hose connections, then reduce the pressure by disconnecting the hose very slowly and carefully.

Connect K-Jetronic pressure tester VAG 1318 with Adapter set VAG 1318/17 on hose.
Check delivery rate again.

If the minimum delivery rate is not achieved this time:

Replace fuel filter.

If the minimum delivery is not achieved once again:

Remove fuel delivery unit and check if filter strainer is dirty.

Only if no error was found to this point:

Replace fuel delivery unit.

If required delivery rate is achieved but a problem in the fuel supply is still suspected (e.g. intermittent failure of the supply):

Check pump current consumption as follows:
Reconnect all unfastened lines.

Fig 5: Measuring Current Draw Of Fuel Pump Using VAG 1715

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Using current probe, connect Multimeter VAG 1715 to green/yellow wire in wiring harness.
Start engine and let it idle.
Measure pump current consumption.

Specification: max. 8 amps

NOTE:

If the problem in the fuel system is intermittent, the test can be conducted during a test drive. This requires a 2 ^nd person.

If the current consumption was exceeded:

Fuel pump is faulty, replace fuel delivery unit, refer to Fuel delivery unit, removing and installing ; Fuel delivery unit, removing and installing.