The Evaporative Emissions Control (EVAP) system collects and stores fuel vapors that evaporate from the fuel tank and from the intake manifold. The EVAP system consists of a charcoal-filled canister, canister purge valve, and the lines connecting the canister to the fuel tank, ported vacuum, and intake manifold vacuum. Some models are equipped with a vacuum switching valve that regulates vacuum to several components - the EGR valve, purge valve, distributor, etc. 1996 and later OBD II systems are equipped with a computer-controlled purge control solenoid, a PCM relay, and an evaporative canister. This system is mounted below the trunk area on the frame. Fuel vapors are transferred from the fuel tank, throttle body, and intake manifold to a canister where they are stored when the engine is not operating. When the engine is running, the fuel vapors are purged from the canister by a purge control solenoid and consumed in the normal combustion process.Poor idle, stalling, and poor driveability can be caused by an inoperative purge control solenoid, a damaged canister, split or cracked hoses, or hoses connected to the wrong tubes. Evidence of fuel loss or fuel odor can be caused by fuel leaking from fuel lines or the throttle body, a cracked or damaged canister, an inoperative bowl vent valve, an inoperative purge valve, disconnected, misrouted, kinked, deteriorated, or damaged vapor or control hoses, or an incorrectly seated air cleaner or air cleaner gasket. Inspect each hose attached to the canister for kinks, leaks, and breaks along its entire length. Inspect the canister. If it is cracked or damaged, replace it. Look for fuel leaking from the bottom of the canister. Apply a short length of hose to the lower tube of the purge control valve and attempt to blow through it. With a hand-held vacuum pump, apply vacuum through the control vacuum signal tube near the throttle body to the EGR and canister purge control valve. If the purge control valve does not hold vacuum for at least 20 seconds, the purge control valve is leaking and must be replaced.For earlier models, label, then detach, all vacuum lines from the canister. Loosen the canister mounting clamp bolt(s) and pull the canister out. For the 1996 and later OBD-II models, raise the rear of the vehicle and disconnect all hoses from the EVAP canister. Disconnect the electrical connector from the EVAP canister vent solenoid and remove the EVAP canister and mounting bracket as a single assembly. For the fuel tank pressure sensor, lower the fuel tank and disconnect the electrical connector from the fuel tank pressure sensor. Remove the fuel tank pressure sensor. For the EVAP canister purge valve solenoid on 2.2L engines, disconnect the electrical connector and hoses from the EVAP canister purge valve solenoid. For the EVAP canister purge valve solenoid on 3.2L engines, locate the EVAP canister purge valve solenoid on top of the upper intake manifold for 1997 and earlier models, or on the coolant pipe adjacent to the left front corner of the throttle body for 1998 and later models. Disconnect the electrical connector and the vacuum hoses and remove the solenoid retaining bolt.
Posted by HondaPartsNow Specialist