Fuel Evaporative Emission Controls (EEC)

Fig. 11 Evaporative Control System:

BMW has made many modifications to the evaporative control system. Check all applicable TSB's for latest EEC system update.
Check all vapor hoses for cracking, restrictions and good connections. It is important, that the fuel cap is in good condition and does not leak.
Some engines are equipped with an mechanical EEC purge valve (no wires to valve). It can be checked as follows:

- Disconnect the EEC purge valve from the vapor hose.
- Blow compressed air through the valve (in direction of flow). With low air pressure (simulating low intake manifold vacuum), only small amounts of air should flow through the valve. With high air pressure (simulating high intake manifold vacuum like full acceleration e.t.c.), the valve should open and have a high air flow. If valve is stuck open, or does not open at all, valve must be replaced.