Checking System

Checking System







HINT: If fuel adaptations indicate too rich fuel/air mixture (adaptation value below 1.0) in several adaptation ranges, this indicates a fuel malfunction. The fault may be caused by too high fuel pressure for example. To find the problem, proceed as follows:

- Check that the oil level is between the minimum and maximum markings
- Check the induction system for clogs and loose components (such as a loose air guide in the air filter holder).

HINT: Adaptations may show rich fuel/air mixture if several cold starts with short subsequent driving time have been performed (e.g., moving cars) and thus the engine oil has been contaminated by gasoline. This affect on the adaptations disappears after driving for some time since the fuel vapors are combusted by the engine.

- Check the EVAP-valve for leakage.

HINT: A valve that does not seal constantly leaks fuel vapors, which thus affect the adaptations.

- Engine running.
- Check fuel pressure for high fuel pressure.
- Ignition on
- Check residual pressure for too low residual pressure.

Remedy as necessary.

HINT: Normal fuel pressure at idle and warm engine shall be approx. 480 kPa. The residual pressure when the engine is off and the ignition is on shall be approx. 100 kPa lower than during idle. If the residual pressure is too low, one malfunction cause may be leaking (non-sealing) injectors, for example.

Other Information
- Air leaks in the intake system, checking
- Checking for air leakage in the exhaust system


Continue: Refer to Checking Mass Air Flow Sensor. Checking Mass Air Flow Sensor