Q: What is the purpose and function of the Evaporative Emission Control System,Canister Purge Valves and Canister on Pontiac Grand Prix?
A: The system is intended to collect and accumulate fuel vapors which evaporate from the fuel tank, the throttle body and the intake manifold. The Evaporative Emission Control System or EECS or EVAP comprises the canister which is charcoal-filled and the tubes joined to the fuel tank as well as ported vacuum. In the '95 through '99 models, the EVAP canister is located in the left-rear fenderwell, beneath the liner, while models made from 2000 on incorporate an EVAP canister which is mounted on the top of the fuel tank, through the use of a built-in fuel filler module that has the EVAP canister located in it; to get to the canister, it is necessary for the fuel tank to Fuel vapors are collected and stored in the canister when the engine is turned off, and returned to the combustion chamber when the engine is on. For all other engines, except 2.2L and 2.5L, the ECM/PCM controls a solenoid valve for vacuum management to the charcoal canister - this valve closes under cold or idle state, and opens with engine warm-up. With 2.2L and 2.5L engines, a purging is done using a purge valve located in the engine compartment. Problems which include but not limited to poor idle, stalling, driveability problem can be attributed to a faulty purge valve, damaged canister, or affected hoses. Any signal that the MOTORHEAD has lost fuel, or got an obtrusive smell of the fuel, may mean leakage of fuel line, damaged canister, or problems with vapor or control hoses. The individual hoses must be checked for kinks and cracks, and so also the canister. If leaking, the canister and the hoses are required to be replaced. For component replacement there is necessity to remove the access cover of the left rear wheel to get to the canister, then, separate and label vacuum hoses, then remove the canister, and assembly is done in reverse. The vacuum hoses and electrical connector of the purge valve should be marked and then disconnected, and the mounting bolts should be unscrewed in order to remove the purge valve while the procedures for installation of the purge valve is also reverse of removal.