I've been tryin to figure out what excatly does the vacuum canister do? I have a 2000 xj that I just bought and it's missing the canister. I have several problems that I am facing and what to know If the missing cannister is causing it. Here's a list of what I am experiencing. Luke warm heat(have a new thermostat installed) whn I put my heat on my jeep idle fluctuates and feels like I am lacking power when driving. With my gas tank it is really weird. When I'm at the pump tryin to fill up I can only add about 3 seconds worth of gas before it clicks off and I got to repeat this just to put in gas. When I take a corner and get a little sideways or attempt to do a donut my jeep cuts out and almost dies but comes back. Is this coming from the faulty vaccum as well? I really need to know because I am having it up to here with this f**** jeep. Please help thank you

 

Which vacuum cannister..the fuel tank vent or your AC control?

Either one, if the vacuum ports aren't plugged, will give you poor performance, and will cause other vacuum controls, like your heat and AC, to not operate properly.

Also, it sounds like your fuel tank is not venting, if the line from your tank to the fuel tank/vent cannister is plugged. In the days before the this cannister, the fuel tank was vented to atmosphere.

 

Where is the fuel tank valve? I'm not excatly to sure on what It is called but my lines from my manifold go over to it so I want to say the ac cannister?

 

Sorry I meant fuel tank vent

 

On most vehicles the fuel tank vent line to the charcoal cannister should be a line following your fuel lines back to the tank, there is also a line from the charcoal cannister that vents passively to the TB. Sounds like you are having more than 1 vac/vent issue.

http://www.scribd.com/doc/3503723/Je...14-Fuel-System

 

I know the lines you are talking about. There are two, one big and one smaller? Well these lines are are broken in a spot right below the drivers door. So they are not connected. What is a tb and and where is the charcol cannister? Right in front of my gas tank there is a sort of square looking box with lines coming out of it. What is this?

 

TB is throttle body. The broken lines under your vehicle, are they capped off? I am not sure what the terminal at the tank does, somebody with more Jeep knowledge will be on soon, good luck.

 

No they are not capped off. I know I have major vacuum isuues but would this cause for problems stalling and trying to add gas?

 

It sounds like the tank isn't venting, making it hard to add gas. The missing vac lines if not capped will give you problems. These things are engineered to work under specific routings and hookups, if they are changed it throws everything off.

Thats all I know about it, with my basic knowledge. I am sure someone will be on that knows all the tricks.

 

Ok thanks for your help. Will a chitlin book show me the routing diagram I need?

 

There should be a vacuum routing diagram under your hood.

 

The chilton books will help out on most things. But i have found some issues that are not in them. The best book to get is the factory service manual. I found mine on ebay fairly cheap. But someone passed this link along to me so i will share it with you guys. Its an online place with most service manuals. Very good info you should be able to find what you need

 

Wow! The amount of bad information being given to to the OP is incredible!

The gas tank has a vent tube next to the filler tube. Crawl under your rig and pull the sheet metal cover and you'll see it. It allows air to leave the tank as the gas you're adding displaces it. I's either kinked or plugged up.

Your fuels system is a returnless system. There is only 1 fuel line from the the tank that delivers fuel to the manifold. There is one line from the fuel tank to the EVAP cannister/purge valve.

The broken line is probably the line that connects the gas tank vent to the EVAP Cannister, fix it. That line is connected tot he tank at the Roll Over Valve and without it the fuel tank is venting to the atmosphere and not into the Evap Cannister.

 

So where is this incredible bad info? I said that the fuel tank isn't venting somewhere, (I am still learning about the Jeep specifics) I said that disconnected vac lines will give poor performance, and that if the vac lines to the AC canister are not hooked up, his controls won't work properly. I also used the words "most" vehicles and "basic".

If you are talking about the location of the vent being incredible bad info, relax!

 

Sorry, rough start to the day and not nearly enough coffee....yet.

The vacuum system has nothing to do with filling the tank.

His heating issues are probably caused by a missing or disconnected vacuum cannister.

The stalling, or near stalling issue may be result of the open fuel tank vent line (to the Purge valve). This line is connected to the roll over valve.

To the OP:
Download the FSM from the site linked to above and read the chapter on Emissions.