Air Injection: Description and Operation

Secondary Air Injection

The function of the secondary air injection system, with one secondary air valve per cylinder bank, each of which is pressure opened by a pump, is the same as in the current 997 vehicles. The secondary air valves with additional check valve were adopted from Cayenne Turbo.







The following switch-on conditions apply to activation of secondary air injection when the engine is started for the first time:
- Engine temperature (coolant): 14 °F (- 10 °C) to 108 °F (42 °C).
- Time: Max. 120 seconds after engine start
- Mass air flow as switch-off condition: Secondary air injection is switched off after a time delay as from a mass air flow of greater than 200 kg/h.