evap sys

Not sure if this should be here or in oem tech, but here it goes. 98 xj to start with. I removed the evap system when I did my rear 4 link. There was really no way around it... Now the check engine light is on... Big surprise. Has anyone figured out a way around this? There are 2 units under the hood. One looks like a selinoid with 2 ports and the other is a vacuum valve of some sort. I tried leaving them hooked up as far as wires and vacuum, but the light is still on. Not really interested in hooking it back up as I have already tossed everything in the trash months ago. Just want to get rid of the light.

pull the bulb.

Ya, that was kinda my next choice.

I was not really serious on that one. You really should figure out how to get a working evap system back in place. My canister being bad affected my mileage, and without it pulling the fumes away from the tank it will be more of a hazard in an accident.

Is this a trail rig? Or does it see the highway?

The best way would to get the light out is to relocate the charcoal canister and vapor lines to the fuel tank. The other items you talk about are most likely the purge solenoid and the leak detection pump.

Its a daily driver. Does anyone know why they changed from having the evap set up in the front 96 and old to having in under the rear set 97+? I could change over to the older set up if it will work. I just don't have any usable space to put it anywhere near where it was. It has been without for a long time. I am still getting 15-16 mpg with dana 60s and 37s, so I think the mileage is still great. Runs perfect. I have plans of just going to a fuel cell anyways, so I would like a way to really fool the computer into thinking its there.

ipkyss said:

Its a daily driver. Does anyone know why they changed from having the evap set up in the front 96 and old to having in under the rear set 97+? I could change over to the older set up if it will work. I just don't have any usable space to put it anywhere near where it was. It has been without for a long time. I am still getting 15-16 mpg with dana 60s and 37s, so I think the mileage is still great. Runs perfect. I have plans of just going to a fuel cell anyways, so I would like a way to really fool the computer into thinking its there.

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Federal regulations made vehicle manufacturers test the fuel system for leaks. The system started in California in 1996, and nationwide in 1998. There might be a way to use a 97 XJ federal certified engine controller in place of the 98. You may have other issues, but it just might work.

I still say it will be easier to just relocate the canister. Go buy the 97 evap stuff from a junkyard and just shorten/adapt the lines. You can mount the stuff under the hood, as long as everything is hooked up right.

Mine blew apart the top first time it saw 10 lbs. of boost. I just disconnected the reference. Mine is OBD1 though so there is no CEL.

Throwing away the evap system was probably a BAD idea. Did you not think removing emissions equipment would set off a CEL?? You might have been about to reroute the lines but now you're screwed. Evap is one of the major checks in an OBDII vehicle.

I'm sure there must be a way to electronically trick the pressure sensor into thinking it has vacuum. Grab a factory wire diagram and a few days at the work bench, you might be able to do it, but it likely won't be easy.