Hi Strathroy,
Are you referring to the Reed Valves in the top of the cylinder head for the Secondary Air Injection system ?
Service Manual 10.147 - Secondary Air Injection :"The secondary air injection system is an aid to reducing levels of pollutants in the exhaust gases.
It does this by introducing a small amount of air into each exhaust port as the exhaust valve opens.
The introduced air helps promote further combustion of the fuel mixture after it has left the combustion chamber.
At certain specific engine speeds above idle, ( determined by factory programming of engine management system ),
the secondary air injection control valve is opened by the ECM and allows an air feed into the secondary air system where,
each time a pair of exhaust valves open, the exhaust gases in the exhaust port create a depression which causes
reed valves in the secondary air injection system to open.
When open, the depression in the exhaust port draws air from the control valve, through the open
reed valves,
into the exhaust port. This air promotes combustion of the exhaust gases in the ports and the header system.
At other engine speeds, the system is disabled by closing the control valve in the system."
