Evaporative Emissions System: Testing and Inspection

INCORRECT OPERATION MAY CAUSE:

^ Poor idle, stalling and poor driveability, check for:

- Inoperative bowl vent valve
- Inoperative canister control valve
- Damaged canister
- Hoses split, cracked or not connected to the proper tubes.


^ Evidence of fuel loss or fuel vapor odor, check for:

- Liquid fuel leaking from fuel lines, fuel pump or carburetor
- Cracked or damaged canister
- Inoperative canister control valve
- Disconnected, misrouted, kinked, deteriorated or damaged vapor hoses, or control hoses
- Bowl vent hose misrouted
- Air cleaner or air cleaner gasket improperly seated.

MAKE A VISUAL CHECK OF CANISTER
^ Visual check of charcoal canister
- Cracked or damaged, replace canister.
- Fuel leaking from bottom of canister. Replace canister and check operation of total system.
- Check filter at bottom of canister. If dirty, plugged, or damaged, replace filter



THERMOSTATIC VACUUM SWITCH

With engine temperature below 100~F apply vacuum to manifold side of switch. Switch should hold vacuum.
Raise temperature of engine to above 122~F and vacuum should drop off. If switch fails either test, replace it.