EVAP Canister Q&A

MtnLuvr · **Posted:** Mon May 24, 2010 8:35 pm

For all the LOST members who don't get into the KK section much where I posted this thread, anyone know anything about the EVAP Canister, including relocation considerations? Does the KJ have such a thing? On my KK, its located on the driver's side back by the rear bumper and gas tank fill tube and looks like the below (except probably without the damaged plastic mounting bracket :shock:

):

I'm interested in relocating it. I wonder if it can be reoriented to be horiztonal rather than vertical. Anyone know?

For those unfamiliar with this, Jeep's KK service manual describes the vapor canister as follows:

Quote:

A maintenance free, EVAP canister is used on all vehicles. The EVAP canister is filled with granules of an activated carbon mixture. Fuel vapors entering the EVAP canister are absorbed by the charcoal granules.

Fuel tank pressure vents into the EVAP canister. Fuel vapors are temporarily held in the canister until they can be drawn into the intake manifold. The duty cycle EVAP canister purge solenoid allows the EVAP canister to be purged at predetermined times and at certain engine operating conditions.

The EVAP canister is also to be considered as part of the ORVR system.

Where the ORVR sytem is described as:

Quote:

The ORVR (On-Board Refueling Vapor Recovery) system consists of a unique fuel tank, flow management valve, fluid control valve, one-way check valve and vapor canister.

with operation as:

Quote:

The ORVR (On-Board Refueling Vapor Recovery) system is used to remove excess fuel tank vapors. This is done while the vehicle is being refueled..

Fuel flowing into the fuel filler tube (approx. 1” I.D.) creates an aspiration effect drawing air into the fuel fill tube. During refueling, the fuel tank is vented to the EVAP canister to capture escaping vapors. With air flowing into the filler tube, there are no fuel vapors escaping to the atmosphere. Once the refueling vapors are captured by the EVAP canister, the vehicle's computer controlled purge system draws vapor out of the canister for the engine to burn. The vapor flow is metered by the purge solenoid so that there is no, or minimal impact on driveability or tailpipe emissions.

As fuel starts to flow through the fuel fill tube, it opens the normally closed check valve and enters the fuel tank. Vapor or air is expelled from the tank through the control valve and on to the vapor canister. Vapor is absorbed in the EVAP canister until vapor flow in the lines stops. This stoppage occurs following fuel shut-off, or by having the fuel level in the tank rise high enough to close the control valve. This control valve contains a float that rises to seal the large diameter vent path to the EVAP canister. At this point in the refueling process, fuel tank pressure increases, the check valve closes (preventing liquid fuel from spiting back at the operator), and fuel then rises up the fuel filler tube to shut off the dispensing nozzle.

I'd appreciate any insight anyone can offer. I want to relocate the EVAP canister for better off-road clearance on the back of my KK. :JEEPIN:

Thanks ya'll.

JustinP · **Posted:** Tue May 25, 2010 4:37 pm

Im very interested in this as well, someone rumored to me that there is an aftermarket flash, that will allow you to eliminate it and all of its componentes completely with no engine light. I havent been able to find it yet. lousy information giver

There is a relocation kit out there for the JK. Ive never seen one for the KK tho. Sorry this wasnt much help. :oops:

MtnLuvr · **Posted:** Tue May 25, 2010 8:38 pm

JustinP wrote:

... There is a relocation kit out there for the JK. Ive never seen one for the KK tho. Sorry this wasnt much help.

Thanks for the tip....however, looking at the JK EVAP Canister relocation kits, they don't seem to be that big a deal but best I can tell they all seem to keep the EVAP Canister in the same (horiztonal) orientation as it was originally on the JK. As you can see on the KK, the EVAP Canister is oriented vertically. I'd like to know if I could reorient it to horizontal and it still work appropriately. Is there some venting to it? If tilted on its side, would there be some problem with the media inside versus the "ports" on it?

Anyone have any info?

MtnLuvr · **Posted:** Tue May 25, 2010 8:50 pm

Here's a little explanation on the EVAP system: http://www.aa1car.com/library/evap_system.htm, including operational principal of the EVAP Canister.

And for those wishing a video explanation: http://www.youtube.com/watch?v=IzfR84T6pBY (but read by a computer-type voice, although it includes some diagnostic measures).

tjkj2002 · **Posted:** Tue May 25, 2010 9:00 pm

JustinP wrote:

Im very interested in this as well, someone rumored to me that there is an aftermarket flash, that will allow you to eliminate it and all of its componentes completely with no engine light. I havent been able to find it yet. lousy information giver

There is a relocation kit out there for the JK. Ive never seen one for the KK tho. Sorry this wasnt much help. :oops:

No such thing as being able to eliminate the EVAP system with no check engine light.

EVAP Canister Q&A

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