No EVAP system in my YJ

rgirardi

Member
Joined
Mar 17, 2021
Messages
37
Location
Raymond NH
Hi
I have a 1988 YJ that I have removed the 4.2 and replacing it with a 4.0. I bought the jeep and there is no EVAP canister and the vacuum lines are all removed. Without having to source all the parts and rebuild the entire system including the metal line from the tank is there another way out of this issue?
Thanks
Ralph
 
There isn't much "evap" to the 4.0 in the YJ. The tank vents it's expansion through the small hardline to the charcoal canister. The engine sucks from the charcoal canister to burn what gets vented there. The engine pulls that through the airbox before it goes into the engine. The rest of the vacuum system is just the hoses from the valve cover to the airbox and the intake manifold which could stay, and then the accessories that use vacuum such as the fuel pressure regulator, brake booster, MAP sensor, and heater passenger side inlet flap.

There is a small line going from the canister to the intake manifold but I'm not sure what it's purpose is with the larger hose going to the airbox. I would imagine you could delete the canister entirely, cap the airbox and intake manifold hookups that it went to, and be done with it. The only thing after that would be how you let the tank vent. Might smell fuel all the time.

The engine definitely shouldn't need the charcoal canister to function properly.
 
I can't think of any great options unfortunately. That's kind of the whole point of the canister. It sucks that the parts are hard to find and not in good shape whne you do find them.