Mopar 4891731AA Valve-Linear PURGE

The EVAP system stops fuel vapors from leaving into the atmosphere and the vapors are routed to the EVAP canister. The NVLD pump monitors the temperature and pressure of the fuel vapors. To check for excessive fuel vapor pressure, remove the gas cap and listen for pressure release. The canister purge solenoid and NVLD pump can be replaced by disconnecting electrical connectors and hoses. The canister can be disconnected from hoses and mounting brackets.

The EVAP system absorbs fuel vapors from the tank and releases them into the engine intake. It utilizes a canister filled with activated charcoal and a two-way valve to vent fuel vapors. The PCM operates a purge control solenoid to open a diaphragm valve in the canister. A leak detection monitor system is also in place to detect any leaks. Component replacement involves removing and installing the EVAP canister, purge control solenoid, and leak detection pump.

This system is employed to capture and contain fuel that volatilises from the fuelling system in a manner that the volatile hydrocarbons do not leak into the environment. It is made of a canister containing charcoal, a canister purge valve, a rollover or pressure relief valve and other hoses and tubes. In case the fuel tank pressure rises to 3psi, as a result of evaporation, the pressure relief valve opens thus allowing the fuel vapour to be channeled to the evaporative canister where it is absorbed by charcoal. For use, as the engine warms up, these vapors are either led to the intake manifold or the air cleaner for burning. Purge valve of canister depends upon the intake manifold vacuum; some models use coolant temperature switches, or computer controlled solenoids to offer the purge. Vents the fuel filler cap in case of occurrence to excessive pressure or vacuum used by the relief valve. To service the foregoing components as well as the fuel filler cap gasket and inspect the hoses and lines with a view of identifying any signs of damage on them. Signs that indicate problems are foul smells of fuel coming from under the bonnet or from the back of the car. The purge valve is checked with a vacuum pump and the purge solenoid is checked with battery voltage. For replacement, remove the negative battery terminal, get to the correct position and unscrew the canister purge valve or the EVAP canister and for reassembly, assemble them in the reverse manner. On some models, the leak detection pump can be detached from the bracket; on automobiles fitted with Fuel Tank Pressure sensor, remove the battery, release fuel tank pressure, and remove Fuel Tank Pressure sensor; when replumbing, do not forget to check on or lubricate the O-ring on the sensor.

The EVAP system absorbs fuel vapors from the tank and releases them into the engine intake. It utilizes a canister filled with activated charcoal and a two-way valve to vent fuel vapors. The PCM operates a purge control solenoid to open a diaphragm valve in the canister. A leak detection monitor system is also in place to detect any leaks. Component replacement involves removing and installing the EVAP canister, purge control solenoid, and leak detection pump.