Genuine Chevrolet Astro Canister Purge Valves

Chevrolet Astro Canister Purge Valves Parts Questions & Experts Answers

• Valve,Evap Emission Canister Purge Solenoid
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  Q: What is the function of the Evaporative Emissions Control System, Canister Purge Valves and Vapor Canister and how does it operate on Chevrolet Astro?

  A:

  The Evaporative Emissions Control System (EVAP) work by confining fuel vapor inside the fuel system hence keeping it from escaping into the atmospher in a similar manner to the PCV system, but trapping the vapors inside the fuel tank until the pressure reaches a level that unseats the pressure relief valve wherein the vapors are redirected to a carbon canister for a brief time. When specific engine parameters are met vacuum from the manifold opens purge control valve to result into allowing the vapors to be drawn into the intake manifold for combustion. Three methods control this process: a ported vacuum source through the Thermo Vacuum Switch (TVS), manifold vacuum accompanied by an EVAP purge control valve, and an EVAP Purge Control Solenoid of the later models. The carbon canister is located at the different positions depending on the model year of your vehicle, if your vehicle model is before 2000 it is located in the engine compartment and if it is after 2000 it is placed underneath the car. Signs of EVAP system failures include fuel smell or a raw fuel leakage with prominence during hot weather. From 1996, models are equipped with a fuel tank pressure sensor that checks the leakage of vapor and sets a trouble code and the SERVICE ENGINE SOON lamp, typically due to a poorly tightened gas cap. The fuel filler cap is incorporated with a safety feature that is the two-way pressure-vacuum relief valve. To do this self-test the vacuum and vapor hoses should be checked for signs of wear and tear, the carbon canister should be examined and the gas cap seal should be examined. These tests include determining the presence of vacuum at three temperatures for the TVS and EVAP purge control solenoid. The vacuum-operated purge control valve should open very little when no vacuum is applied to it and quite a lot when vacuum is applied to it. Component replacement is performed at the TVS, solenoid, and carbon canister, and disconnecting/reconnecting with attention paid to the condition of seals; filters must be clean for particular components.