94 Mustang Vacuum lines


Founding Member
Jun 13, 2000
Hastings, MN, USA
I am in the process of trying to resolve my surging idle issue with my mustang, after changing the heads and installing a cam. I started by replacing most of my lines with new vacuum lines to eliminate a vacuum leak. I replaced the small line going under the passenger fender into that box. I noticed the larger line in there that comes off the box (or canister?) It goes up towards the front of the car, it goes into a smaller hard plastic line and then just stops and nothing is plugged into it.

I had a chip burned for my car and had the EGR turned off (also removed it from car..etc) how important is this open line at this point? Should I just plug it?

I have looked at some vacuum diagrams but not sure where this thing should go..
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This black plastic hose, was it clipped to the bottom of the passenger frame rail? If so, that's just a vent for the charcoal canister.

anyone want to describe what the charcoal canister does? I'm pretty sure I know but I just can't put it into words. Don't want to give out bad info.

I thought it was to vent fuel vapor from the tank.. That line does go up the frame rail. I guess I'll leave it be then lol

This is how messy my lines are..


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You guys have the EVAP system correct. THe CC is just a closed mechanism for venting fuel tank vapor. There's a cavity at the top of the tank with a filter. This separates liquid fuel from vapor. Vapor escapes the maze and goes to the CC, where the gasses compile till the purge solenoid opens. The solenoid dumps the vapors back into the intake for consumption. Totally closed (nice if you have a pilot light in your garage). I consider this to be more of a safety thing than an emissions thing.