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ZUKIWORLD Discussion Forum => Technical Discussion - Beginner / Repair => Topic started by: yellow2000S/R on February 05, 2012, 02:17:39 AM

Title: Gas Tank Pressurizing
Post by: yellow2000S/R on February 05, 2012, 02:17:39 AM
My gas tank in both my 96 Tracker 2 door and 94 Sidekick 4 door pressurize. I was wondering if they were supposed to. I'm use to a small hiss when I take the cap off other vehicles but both the Tracker and Sidekick put a lot of vapors out when I remove the cap. The Sidekick gas tank actually made a thump sound the other night from it going back to the shape it should have been.

Too dangerous for me if. If I was to be offroading and snagged the tank bad, sparks from dragging on rocks + vapors = boom.
Title: Re: Gas Tank Pressurizing
Post by: Skyhiranger on February 05, 2012, 06:56:10 AM
It's normal.
Title: Re: Gas Tank Pressurizing
Post by: rascott on February 05, 2012, 07:02:16 AM
mine also pressurizes. i have learned to release the gas cap before working on the fuel system.
i don't think i'ts developing the kind of pressures you indicate.
mabe your gas cap is bad(i think there is a relief valve in it?).
Title: Re: Gas Tank Pressurizing
Post by: Skyhiranger on February 05, 2012, 07:06:56 AM
mine also pressurizes. i have learned to release the gas cap before working on the fuel system.
i don't think i'ts developing the kind of pressures you indicate.
mabe your gas cap is bad(i think there is a relief valve in it?).

From what I recall, the gas cap is set up to let air in, but not let air/fumes out.
Title: Re: Gas Tank Pressurizing
Post by: fordem on February 05, 2012, 06:54:19 PM
My gas tank in both my 96 Tracker 2 door and 94 Sidekick 4 door pressurize. I was wondering if they were supposed to. I'm use to a small hiss when I take the cap off other vehicles but both the Tracker and Sidekick put a lot of vapors out when I remove the cap. The Sidekick gas tank actually made a thump sound the other night from it going back to the shape it should have been.

Too dangerous for me if. If I was to be offroading and snagged the tank bad, sparks from dragging on rocks + vapors = boom.

Pressurized or unpressurized, there WILL be vapors in the tank - I can suggest a little experiment if you don't believe - so let's assume your tank is not pressurized, you're off roading, and snag the tank bad, sparks from dragging on rocks + vapors will still = boom.

Emission control requirements are what dictate that the tanks be "sealed" systems - no the caps aren't vented - there should be a vapor recirculation system with a charcoal canister and a purge valve that is controlled by the ECU to release the vapors to the intake manifold so that they are burned in the engine, make sure yours is functional.
Title: Re: Gas Tank Pressurizing
Post by: LowRangeWilliam on February 05, 2012, 08:57:40 PM
your tank should not pressurize enough to expand the tank and you should hear pressure release when you loosen the gas cap that is normal