OT Chev S10 ....Gas smell

[Superheat9]

Daughter has a 94 Chev S10. There is a gas smell when it is parked. 2.2 liter. I have looked and cannot find a gas leak. The service manual points to the Charcoal canister, part of the emissions. I called and it will cost 160.57. What else should I check before ordering this part? What would happen if I bypassed or install a substitute filter? Also could there be a way to back flush or replace internals?

[baggrfred]

You are probably on the right track about it being the vapor canister. The charcoal inside them gets fuel logged usually from topping off a fill up after the pump has clicked off initially. Lots of people do it and don't realize that in the long run, that is the result. I don't know if there are aftermarket ones any cheaper but it is part of the emission system and can cause a code to pop up down the road if you don't change it. Will also cause a code if it is bypassed or eliminated. Emission testing will also be an issue. First, check for all of the hoses are still on the canister and on the fill neck. If all is ok with that, you will probably have to choke down purchasing the replacement. Check availability and prices from A/M parts stores.
Baggrfred

[IBARider]

 
  Yup, make sure your hoses and everything is intact.  Basically make sure it is able to purge or it will build up with gas and smell and a new cannister won't fix it  looks like CA models used a purge solenoid....


PURPOSE
The Evaporative Emission (EVAP) control system limits fuel vapors from escaping into the atmosphere by storing the vapors in an activated carbon (charcoal) storage device (vapor canister) until the engine is able to use the extra fuel vapor.

When the engine is able to use the extra fuel vapor, the fuel vapor is purged from the carbon element by intake air flow and consumed in the normal combustion process.

The fuel tank is sealed with a fuel cap that is NOT normally vented to the atmosphere. The fuel tank cap has a safety valve which allows for both pressure and vacuum relief.

OPERATION
Fuel vapors from the fuel tank are purged and flow into the vapor canister tube labeled 'tank" and are absorbed by the carbon. The canister is purged when the engine is able to use the extra fuel vapor A vacuum source is applied to the vapor canister tube labeled "purge" to draw fresh air through the top of the canister. The air mixes with the fuel vapor and the mixture is drawn into the intake manifold to be consumed in the normal combustion process.
While the canister is purging, fresh air is drawn in through the air inlet at the top of the canister. Air flows to the bottom of the canister and forces the vapors out the "purge" tube.

Canister Purge Solenoid
California equipped EVAP systems use an electrically controlled solenoid to cycle the vacuum to the purge canister. The control module cycles the solenoid when engine coolant temperature is greater than 45°C or the short term fuel trim cell is less than 122 counts.

Fuel Pressure Control Valve


 



Fuel Tank Cap
The fuel tank is sealed with a fuel cap that is NOT normally vented to the atmosphere. The fuel tank cap has a safety valve which allows for both pressure and vacuum relief.











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[Reddog74usa]

I would look for a junk yard part befor spending that kind of money

[89springer]

get a evap test done before throwing parts at it.  it may not be the evap system at all. have you checked items under pressure injetors, lines, pressure regulator. not saying you are not on the right track but; you can spend alot of money and not even come close to fixing it. a 30 year gm tech. springer

[Superheat9]

Thanks for the info..... I will double check the hoses on canister. Never checked the fill tube, overflow or gas cap.  I don't live in a state that requires emission test. Last time I checked that want 150 to run a diagnostic check. Called the auto part outlet and no one sells the part.

Again thanks for the help