Pressure Switch in line with Charcoal Canister!
 

I am putting my Autotune Pressure switch on the vacuum line going to the charcoal canister.

First I encounter problem with the pressure switch not activiating while in boost. That was when I had the switch "t" between the solenoid and canister, I guess when it dosen't open there is no air passing through over.

Second, I relocated to the next vacuum line from the Intake Manifold to the silenoid. That worked, but the switch had a momentary delay, I am guessing it takes a slight moment to fill the can with pressure than the pressure switch reacts.

I am still trying to find a right place for the pressure switch with those lines. Will it be possible to leave the Charcoal Canister Silenoid out of service? (taking out Vaccum line in all)?

Hook in to your cruise control hose...(or cap)

I had a simular problem with my afpr hooked up to that line...
I guess the solenoid opens and the afpr did'nt see boost...

If you take the can out it might smell like gas. Mine is disconnected (I managed to break the vacuum solenoid :td: ) and it is just fine. If you search people have done it, but I would just leave it.

The ideal position for the switch is in the same vacuum line as your boost gauge. This way you can adjust your switches activation point accurately. For my switch I used the second vacuum port on the throttle body. I ran the vacuum line to the fender, then put a T with the boost gauge and switch on it.

Are your vacuum ports on the throttle body being used by something else? And also you will want your switch to activate around 2psi. This way while your just driving your not bouncing between on and off.

I tapped here, see pic, and it has worked well with the vacuum line serving the pressure switch, boost gauge, and Map. The extra tap is for the BOV when I decide which one to use!

One of the guys at my local tuner shop said he used a fuel distribution block and converted it to a vacuum block. I really want to make a vacuum block, the more things I put on the car the more ugly plastic "T's" I have.

Jojonz, that looks like a really good solution.

Silly questions perhaps but....
Whats the Charcoal Canister for anyway besides being a big ugly lump in the engine bay ?
Can it be removed and are there instructions ?

emissions. You could remove it and the solenoid, and put a filter from an rc car or something small on the return line to the fuel tank. It might smell like gas sometimes though.

It's my impression that the charcoal cannister filter gas fumes while idling. Part of the emmissions system. From reading what others have done, you can remove it on you '91.

Edit: You beat me to it :)
Some take the line to the tank out but leave a small section at the tank with a small filter back there. Then use that existing open spot in the rail for WI feed line.

not meaning to threadjack or anything, but the two tubes on the charcoal canister.. which one is the return line. i recently removed mine, but i plugged both lines with a rubber dealio.. could i be causing any harm by plugging them ?

I've try taken out the vacuum line going to the solenoid. The car would buck and will easily stall.

did you cap the vacuum line back to the TB and unplug the solenoid?

Ahh... so I hve to unplug the solenoid! that's where it went south! keke

That's where I made the BOO BOO! :crx:

well that looks to be an inline pressure switch...I wonder if capping it like that wouldn't have screwed it up. since you couldn't really blow through it or pull vacuum from it to engage the "switch"

Capping one side makes no difference, it can be used within a run or dead-ended. It can't be put on a line that requires a large flow, because it will restrict the flow.

Are there any instructions to be found on taking this lump out ?
Pics of the lines/solenoid etc that can also be binned ?
What to plug etc ?

i just posted instructions :P

https://www.miataturbo.net/forums/at...2&d=1175613119

the guy with the blue vacuum line attached to it is the solenoid
plug whatever you removed except for the return line.

So, I take out the cannister, solenoid, plug all lines except for the return line ?
Just like that ?

I'll ask here since everyone seems to be pulling them out. Does anyone have the charcoal canister solenoid they would like to sell/give away? I'm in need of one because I broke off one of the nipples. Thanks!

I was looking at my charcoal canister today and I want to take mine off. There is one vacuum line coming off of the intake manifold going to what I assume is the pressure switch. There is one going from the pressure switch to the charcoal canister. I assume I can just remove both of those lines, unplug and remove the pressure switch, and put a cap over the vacuum line connection on the intake manifold. Is that correct so far?

Next you have two, I assume fuel vent lines, going into and out of the charcoal canister. One goes in the bottom and one goes out the top. Can I just connect these two together?

Thanks fr any help.