everybody hello my name is tim and i must thank all of you for the info i have obtained from these forums i have read so much. i have a 88 iroc-z tpi 5.7l and i have put many hours into tuning this engine. i have some mods but not to a considerable extent. she has now 98,369 original miles and runs beautiful. question a smell of gas fumes in the car while driving mostly though are present at idle too. i am thinking the purge canister myself. exhaust is tight with no leaks. any info is great thanx guys

 

Could be the purge canister. Also check the back of the fuel rail. There is a fuel line hooked up there and usually the o-ring inside wears out and cause the gas smell. It may even be leaking slightly.

 

The gasoline vapors you are smelling (technically, fumes are created by heated metal, vapors are evaporated liquid) could well be from a saturated EVAP canister. If you drive your car only on short trips, the EVAP may not have an opportunity to purge adequately. Also, a failure of the canister purge control, tank vent control valve, or the vacuum and vapor lines may cause a saturated canister. Check the EVAP solenoid valve, vacuum and vapor hose routing, and make sure nothing is obstructing the opening on the underside of the canister.

You can force the canister to purge by connecting a vacuum bypass of the purge control valve and operating the engine for 15-30 minutes. If the system is working correctly and you drive your car under light loads at cruising speeds (highway driving) the EVAP should not saturate. If it is saturated, you can "recover" it by the above method or driving as described.

Other possible sources for fuel vapors are the gas tank cap, tank vent valve (at the tank), fuel tank, filter, or line leakage, injector 'O' ring leakage, fuel pressure regulator leakage, or fuel rail leakage as the Cap'n described.

 

Thanks for expanding on my answer Vader. I appreciate it.