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Thread: Using charcoal canister & vent?

  1. #1

    Default Using charcoal canister & vent?

    While I'm accumulating enough cash to buy a bunch of engine parts including a Sniper, I'm researching the heck of of everything and this forum has been great for that. Here's another area I'm looking for help.

    My car started as factory TBI, but got a carb as part of a significant displacement enhancement. It had a return-style fuel system and a charcoal canister that I kept installed/hooked up, mostly to help vent the fuel tank so it does not build up too much pressure (and rely on the blow-off valve) and to help with fuel vapor smell.

    I've got it configured to purge only in 4th gear (4-speed automatic transmission) and only when the converter clutch is on. I can easily keep this functionality with a Sniper, but...

    What does purging the canister do to the fuel Learn? I'd imagine that a canister 'full' of fuel vapor would run somewhat rich during purge until the WBO2 sensor backed out fuel. Am I introducing some sort of reason for the fuel Learn to wander around a bit until the canister is 'empty' of fuel vapor, then wander back to normal, or is the amount of fuel involved in purging the canister so small that I'm worried about nothing? Anyone with any experience here? Thanks!

  2. #2
    Join Date
    Dec 2009


    Quote Originally Posted by Rumblefish View Post
    ...or is the amount of fuel involved in purging the canister so small that I'm worried about nothing?
    I wouldn't be concerned about the fuel vapor changing the fueling/Learning.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & MT 245/45R17 tires.

  3. #3


    Awesome. That's what I hoped. Thanks for the quick reply!

  4. #4


    Yep, unless you routinely fill your tank clear up to the neck (which can/will flood the vent/canister with liquid gasoline), the amount of fuel vapor collected in the canister and then sucked into the engine is tiny. (Flooding the EVAP system is why 'they' so strongly recommend that you stop the gas pump at the first 'shut-off'. I've seen Toyota's that needed upwards of $1500 repairs because the drivers FILLED their gas tanks.)

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