What does it do exactly? Does a clogged one affect performance? How do I check it?

Thanks

 

I know it filters all unburned fuel vapors through a charcaol filter. It's located in the rear within the rear quater panel, but I can't remember which side. I don't believe it will effect performance, but the car will reak of fuel without it.

 

Pretty much as desribed above. Located in the drivers side rear fender,m behind the fuel filler pipe. All vapor and air vented from the fuel tank passes through the charcoal filled canister, and the charcoal absorbs the hydrocarbon vapors. The remaining air goes out a vent pipe.

When the engine is operating under certain load/rpm conditions, the PCM opens a "purge" solenoid on the passenger side of the intake manifold, and engine vacuum pulls air through the canister, picking up the hydrocarbon vapors. This A/F mixture runs through the "3rd" fuel line to the engine, , through the purge solenoid, and into the small vacuum connection on the passenger side of the throttle body.

In OBD-I, the only diagnostic is whether the solenoid circuit is healthy. In OBD-II, there is the solenoid eletrical check, plus a flow detector to determine if there is "flow during non-purge" or "no flow during purge", all of which will set codes.

The PCM is expecting the small quantity of A/F mixture to flow when it commands the solenoid to open, but the amout is so small I can't see how it would affect performance in any noticable way. At WOT, there isn't much vacuum available, so its not going to affect WOT at all.

If you removed the system, you would have to replace the "non-vented" fill cap with a "vented" cap, and you would notice fuel fumes accumulating at the rear fender. My system was not operating right after I swapped to an aftermarket ECU, and the fumes from C16 racing fuel were enough to bring tears to your eyes when stopping at a light with the window open.

 

Thanks for your replies. Very helpful.