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 V.A.G 1348/3A connected.

Test sequence


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


- Remove filler cap from fuel tank filler neck.







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


NOTE: Press down on fuel line connectors to release.







- Connect pressure gauge V.A.G 1318 with adaptor V.A.G 1318/23 and V.A.G 1318/17 to fuel supply line.
- Push hose V.A.G 1318/1 onto adaptor V.A.G 1318/11 on pressure gauge and hold hose in a measuring container.
- Open pressure gauge cut-off tap.
- The lever then points in the through-flow direction -A-.
- Operate remote control V.A.G 1348/3A while slowly closing cut-off tap until pressure gauge shows 3 bar.


NOTE: From this point on do not move position of cut- off tap.


- Empty measuring container.
- Connect Fluke 83 multimeter to vehicle battery using jumper wires from VW 1594 Adaptor kit.


NOTE: Fuel pump delivery range is dependent upon battery voltage


- Operate remote control for 30 seconds and note battery voltage.







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

Example:
During test, 12.2 Volts is measured at battery. The fuel pump voltage is approx. 2 Volts less than battery voltage equating to a minimum delivery of 200 cubic cm/30 s.

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







- Disconnect supply line from fuel filter inlet.


NOTE: Press down on fuel line connectors to release.


- Connect V.A.G1318 pressure gauge using adaptor V.A.G 1318/17 on 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 blue/red 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.