Vapor canister orientation?

[Kran]

i had to relocate the vapor canister due to installing triple alternators. its currently pointing sideways, would this still allow it to work properly? i have to have it due to emissions testing. i drove it 40 miles like this with no CEL. any info would be great!

 

[Supercharged111]

I'm in for the answer here too. I'm inclined to thinking it shouldn't matter as it's for vapors and not liquid.

 

[PlayingWithTBI]

I'm inclined to thinking it shouldn't matter as it's for vapors and not liquid.

^^^ X2

I would think so too - it's filled with charcoal not liquids.

 

[454cid]

I would keep whichever end GM designed to be up, up. I don't know exactly how it works, but I would imagine that it has dividers and such inside guiding the fuel vapors. If it's turned on it's side, the vapors may not be able to go where they need to go.

 

[Ken K]

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If this is a rectangular shape activated carbon canister, it can be positioned laying flat or upright. I did an autopsy on a rectangular design type and did not know the model, but was GM. The activated carbon is pressed to one end by the use of a large screen covered end cap with a large spring behind it. So the carbon is not loose inside but compressed. As long as the OEM roll-over valve or over fill valve (What ever you want to call it) is used as it keeps raw fuel from getting into the canister hose.

 

[Kran]

You must be registered for see images attach

If this is a rectangular shape activated carbon canister, it can be positioned laying flat or upright. I did an autopsy on a rectangular design type and did not know the model, but was GM. The activated carbon is pressed to one end by the use of a large screen covered end cap with a large spring behind it. So the carbon is not loose inside but compressed. As long as the OEM roll-over valve or over fill valve (What ever you want to call it) is used as it keeps raw fuel from getting into the canister hose.

yes this is the large rectangular one. i have a 99 tahoe with vortec 5.7. the factory tank vapor line, purge hose to intake, and the small air pump/vacuum thing are all hooked up as they were before. entire fuel system is stock (as far as i know)

 

[Ken K]

Yes, 3 fittings;
#1 Purge Valve on intake
#2; Fuel tank vapor line goes into a roll-over valve to get tank fumes.
#3; With 99, This hose goes to the "Tank Solenoid" and has vacuum sensor on fuel pumps' top.

The solenoid is normal de-energized, open all day. Using PWM, the Purge will open when PCM see's the correct conditions as this adds gas fumes into the engine. It watches the #1 02 sensor(s) to stay within fuel trim.
Being open all of the time is where problems happen as it must close & seal during EVAP testing. The air has dirt & dust in it and is pulled into this solenoid all of the time as you drive.

You'll have EVAP software, so warm, at highway speeds and based upon a PCMs' internal clock, the "Tank Vapor" solenoid will close. To "Test" the EVAP's integrity, the purge is opened while the tank solenoid is forced to close. This allows vacuum measured at inches of water. As the vacuum drops and hits 8 in h2o, the purge is closed, with the tank solenoid remains closed...so seal fuel tank, canister, hoses, gas cap and fuel tank solenoid. Over two minutes, the PCM watches the vacuum sensor at the fuel pump. If it looses vacuum to reach 12 in h20 or more, then that's a small leak. The poor fuel tank solenoid is "Normally" mount under the bed, behind the rear wheel and may not seal because of the dirt & dust. These usually are not cleaned, just replaced. This is called the "Enable Criteria" for running the EVAP check, but the tactics behind it.

Sound like you're fine... It just how it works, because the canistor capture fumes when re-fueling, and sloshing around and when the tank is between 80% - 20% is when the EVAP test run. So, if the sender is inop, it will set a code and abort the test...but your gauge will be wonky as well.

 

[delta_p]

Man, I am glad I have a '96. I like that it has a canister, but without the tank sensor and all the EPA EVAP software. On '96 it just opens the purge solenoid and has a vacuum switch to let it know it "is" purging so all is happy.