Fuel Delivery Rate, Checking

Fuel delivery rate, checking

WARNING!
Fire hazard! Do NOT have anything in the area that can ignite gasoline!

Check conditions
^ Voltage supply OK.
^ Remote control VAG 1348/3A connected.

Test sequence
- Remove filler cap from fuel tank filler neck.

WARNING!
Fuel system is under pressure! Before opening the system place a cloth around the connection.
Then release pressure by carefully loosening the connection.





- Pull off supply line -3- and collect leaking fuel with a cloth.





- Connect pressure gauge VAG 1318 with adaptor 1318/10 to the fuel supply line.
- Push the hose VAG 1318/1 onto the adaptor VAG 1318/11 on the pressure gauge and hold hose in a measuring container.
- Open the pressure gauge cut-off tap.
^ The lever then points in the through-flow direction -A-.
- Operate remote control VAG 1348/3A while slowly closing cut-off tap until pressure gauge shows 3 bar.
^ From this point on do not move position of cut-off tap.
- Empty the measuring container.
- Connect Fluke 83 multimeter to vehicle battery using jumper wires from VW 1594 Adaptor kit.
^ Fuel pump delivery range is dependent upon battery voltage
- Operate remote control for 30 seconds.





- Compare quantity of fuel delivered with chart.
*) Minimum delivery cm3/30 seconds
**) Voltage at fuel pump with engine not running and pump activated (approx. 2 Volts less than battery voltage).

Example:
During test, 12.5 Volts is measured at battery. The fuel pump voltage is approx. 2 Volts less than battery voltage equating to a minimum delivery of 530 cm3/30 s.

If minimum delivery rate not obtained:
- Check fuel lines for possible restrictions (kinks) or blockage.





- Disconnect supply line from fuel filter inlet.
- Connect VAG1318 pressure gauge using adaptor 17on hose
- Repeat delivery rate check.

If minimum delivery rate now obtained:
- Replace fuel filter.

If minimum delivery rate not obtained:
- Remove fuel delivery unit and check strainer/filter for soiling.

If no malfunctions found
- Replace fuel delivery unit.

If delivery rate is obtained but a fuel supply system malfunction is suspected, e.g. intermittent supply
- Check fuel pump amperage draw as follows:
- Reconnect all disconnected fuel lines.





- Connect Fluke 83 multimeter to green/yellow wire of wiring harness using Fluke 83 inductive pickup accessory.
- Start engine and let idle.
- Measure fuel pump amperage draw.
^ Specification: 8 amps maximum

Note:
If the fuel system malfunction is intermittent, perform the check during a test drive using a 2nd technician.

If amperage draw is exceeded
- Fuel pump faulty, replace fuel delivery unit => Refer to Fuel delivery unit, removing and installing.