1978-79 Models
- Check for correct system (line) pressure. Remove bridge from fuel pump relay and wait 10 minutes. Pressure should hold 25 psi (1.8 kg/cm2 ) for at least 20 minutes. If not, replace fuel pump check valve.
- If pressure holds, but engine operates with an excessively lean mixture, replace fuel filter and test delivery rate. With filter in good condition and pump running for exactly 30 seconds, delivery volume should be 24 ounces (750 cc).
NOTE:
With system pressure correct on Audi 5000, pinch intake hose between fuel tank and fuel pump and turn ignition OFF. If pressure does not drop, replace fuel pump check valve. If pressure continues to drop, replace "O" ring in fuel distributor pressure regulator valve.