Fuel Pump: Testing and Inspection

Checking Quantity Of Fuel Delivered

Tools







Tools and materials

Special tools







Information

Test conditions
- The battery voltage must not be < 12 volts.
If an insufficient delivery rate is determined in the delivery rate test, the measurement on the second scavenging valve of the fuel gallery will be repeated.
- Fuel system parts must not get dirty.

Checking quantity of fuel delivered

Checking fuel delivery rate







1. Pull the cover of the throttle body up and off.
2. Unscrew cap on the front right of the fuel gallery.

WARNING:
Danger of fire and injury.
- Danger of fire due to escaping fuel, e.g. on hot engine components or due to electrostatic charge.
- Danger of fire due to naked flames and sparks, e.g. during welding or grinding work.

- Secure the vehicle, e.g. with a warning sign.
- Wear protective gloves that are fuel-resistant.
- Ensure that there is adequate ventilation and extract all fuel vapours.
- Before opening the fuel lines or fuel hoses, relieve the fuel pressure.
- Collect escaping fuel, absorb it if necessary with a suitable binding material and dispose of properly.
- Pay attention to cleanliness when working on the fuel system.
- Avoid contact with the skin and eyes.

INFORMATION: The fuel gallery is pressurised. Place a cloth near the front of the fuel gallery to prevent fuel dripping onto hot engine parts.







3. Join the test hose to the measuring adapter and connect the other end to the scavenging valve on the fuel gallery.

INFORMATION: For the delivery rate check, a second person should clock the time.







4. Place the open hose end from the pressure regulator in the measuring beaker.

5. Connect jumper lead 26 to two test leads 16 taken from measurement tool set 9684 and use these to bridge the fuel pump. The exact assignment of the contacts can be obtained from - Fuse carrier.

INFORMATION: To avoid incorrect readings, make sure that the hose lines are already full of fuel at the start of the test.

6. Keep fuel pump switched on until fuel emerges from the end of the hose. Then empty the measuring beaker.
7. Switch on fuel pump I (left pump) for one minute. Then monitor the fuel delivered and note the quantity. Now repeat the process with pump II (right pump).

Fuel pump Delivery rate
Fuel pump I (left) > 1.6 l/min
Fuel pump II (right) > 1.3 l/min

If the test delivery rate produced in the test is too low, repeat it at the right scavenging valve of the fuel gallery.

8. On completion of the test, switch off the ignition and remove test tool.

DANGER: Danger of fire due to faulty scavenging valves.

- Only use the special, Porsche-approved valves in the fuel gallery.
- Do not replace scavenging valves by tyre valves.
- It is essential that the plastic cap is also replaced.







9. Press the four rubber elements in the cover onto the four ball socket holders. The mounts must be felt to engage.