Visual Check (Fuel Leak)
- Remove air cleaner and check for any visible fuel leaks. Remove fuel pump relay from relay board. Bridge terminals No. 7 and 8 long enough to establish fuel pressure. Push airflow sensor plate down manually.
- Uniform resistance should be felt throughout travel after slight amount of free travel. No binding should be felt if sensor plate is released quickly. If upward movement of sensor plate is slow, resistance from control piston closely following adjusting lever should be felt. No binding should be evident.
- Push airflow sensor plate completely down and hold there briefly. Slight fuel seepage past control piston is acceptable. If no fuel leaks have been found, go to next test.
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.