Fuel Pump Delivery Rate, Checking

Checking conditions
^ Voltage supply OK.
^ VAG 1348/3A Remote control connected.
- Remove filler cap from fuel tank filler neck.
- Remove the intake manifold cover.





- Open the threaded union -arrow- and catch escaping fuel with a cloth.





- Connect pressure gauge VAG 1318 with adapter 1318/12 to fuel supply hose.
- Push the hose VAG 1318/1 onto the adapter 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 direction of flow -A-.
- Operate remote control VAG 1348/3A and slowly close cut-off tap, until pressure gauge shows 3 bar.
^ From this point on do not change the position of the shut-off lever.
- Empty measuring container.
- The fuel pump delivery range is dependent upon battery voltage. Therefore, connect the multimeter to the vehicle battery using jumper wires from VW 1594 adaptor kit.
- Operate remote control for 30 seconds.





- Compare the quantity of fuel delivered with specification.
*) Minimum delivery CM3/30 seconds
**)Voltage at fuel pump with engine stationary and pump running (approx. 2 volts less than battery voltage).
Example:
During the test a voltage of 12.2 volts is measured at the battery. As pump voltage is approx. 2 volts less than battery voltage then this equates to a minimum delivery of 550 cm3/30s.
If minimum delivery rate is not obtained
- Check fuel hoses for possible restrictions (kinks) or blockages.





- Pull supply hose -1- off inlet to fuel filter.
- Connect pressure gauge VAG 1318 to hose with adapter 1318/10
- Repeat delivery rate check.
If minimum delivery rate is now obtained
- Replace the fuel filter.
If minimum delivery rate is again not obtained
- Remove fuel delivery unit, and check strainer for foreign matter.
If no malfunction found up to this point
- Fuel pump faulty, replace fuel delivery unit
If the delivery rate has been obtained but nevertheless you suspect a fuel supply system malfunction, e.g. intermittent fuel supply
- Check fuel pump amperage draw as follows:
- Reconnect all disconnected fuel lines.
- Remove floor cover.





- Connect Fluke 83 multimeter with inductive pickup on the green/yellow wire in wiring harness.
- Start engine and let idle
- Measure fuel pump amperage draw
^ Specification: 8 amps maximum

Note: If the fuel system malfunction is intermittent, you can perform the check during a test drive, which requires a 2nd person to read the test instruments.

If amperage draw is exceeded
- Fuel pump faulty, replace fuel delivery unit