Fuel Tank Pressure Control Valve (High Altitude Only)

The Tank Pressure Control Valve (TPCV) is used only on altitude applications.

This is a functional check of the TPCV to see if the diaphragm is leaking.

^ Use a hand vacuum pump with a gauge and apply 15" Hg of vacuum to the tube labeled "CONTROL VAC." (Be sure the hand vacuum pump being used does not have an internal leak and the hose connections to the control vacuum tube and pump are secure) The diaphragm should hold vacuum for at least 20 seconds. If it does not, replace TPCV valve. If it does hold vacuum proceed to next step.

^ Apply a short hose to the tube labeled "TANK," and with vacuum still applied, blow into the tube. If air passes through the valve, then TPCV valve is OK. If no air passes through the TPCV valve then it is defective and must be replaced.

^ NOTE: Pressure that is being blown into the valve must exceed the opening point of the valve which is being held shut by a spring.