Fuel Pump Delivery Rate - Checking

Tools

• Metric wrench set
• Measuring container (1500 ml / 50 fl oz or larger)
• Hose to connect to the fuel pressure regulator return outlet
• Hose clamp
• Stopwatch or other timing device
• Catch rags

Fuel Pump Delivery Specifications

Pump Type	Delivery Rate
Most fuel pumps	850 ml / 30 sec (28.7 fl oz)
Pumps with green paint code (Bosch No. 0 580 464 028)	750 ml / 30 sec (25.4 fl oz)

Procedure

Caution: Have rags ready when disconnecting fuel lines. The fuel rail may be under high pressure and fuel can spray if fittings are removed too quickly.

1. Slowly disconnect the return line from the fuel pressure regulator (FPR) going back to the fuel tank.
2. Using a hose clamp, attach a hose to the FPR discharge outlet that is long enough to reach the measuring container.
3. On early cars (pre-1985.5), remove the fuel pump relay from under the dash on the driver's side (left-hand drive).
4. On later-model cars, remove the DME relay from the fuse/relay panel under the hood.

Note: Be ready to start the stopwatch immediately — the fuel pump will start as soon as the jumper is installed.

5. At the panel where the relay was removed, jumper terminals 30 and 87b. (Check terminal labels on the underside of the relay if unsure.) The fuel pump should start — start the stopwatch immediately.
6. Allow the pump to run for 30 seconds, then remove the jumper to stop the pump.
7. Measure the fuel collected in the container and compare to the specification table above.
8. Values significantly below specification indicate a problem with the fuel pump, fuel filter, or fuel damper.