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Im working on restoring the fuel evaporative system into the MY hatch... using half the EJ gear and half the MY gear. I have worked out what to do and have all the parts....

Although... i do like to understand what and why things do what they do.... something i don't understand is the carbon canister. Whats does this do???

I can tell by blowing through the hoses that air appears to come out of underneith the canister. Maybe this works like a filter... filtering fuel particles from the air... and allowing the "clean" air to escape through the bottom.

But how then do these fuel particles get sucked back into the motor. Does the purge control valve control a vacume function sucking the particles into the throttle body??? If so wouldn't this cause a vacume leak seams the canister is obviously not sealed.

Can anyone fill in the blanks or make my little brain understand??

Dave

I'm certainly not too clued up on this topic Dave, but I can tell you that you've certainly got part of it right there. Its basically a filter for fuel vapour, it allows the vacuum system to breathe without emitting fuel vapours. Or something.

To tell the truth all of my carbon canisters have been lost along the way... part of the reason I'm not game to take my coupe over the pits....

Main reason i am fitting it all is because i still have syco fuel pressure building up in my fuel tank... the canister system is created to help fight this. It can't be good for my fuel tank and my entire system to have that much pressure in there.

Dave

Dave, going through the EA82 manual in the "Downloads" section, I found in Part 1 an excellent section 2.1 all about this and more!
Its the emission control section, and yes, it opened my eyes to more of those mystic devices hidden under the bonnet, and how they play a part in the overall tuning with diagrams to lines etc.

I assume that this will give you the basics that you will need that would be generic to all emission control systems.
Cheers, Roger

I can't understand why your tank builds pressure, I've never had a problem in that department.

Does your tank cap have an inbuilt breather?

The tank cap only allows air in if need be... not out. The whole idea is that the carbon canister lets the tank breath. Don;t ask me why u never had the problem... u must have a leake somewhere where the pressure slowly escapes.

Dave

I very much doubt that Dave, as whenever I pop the cap it sucks in a heap of air. Plus I've not had any fuel smell back there, a leak would stink. I am about to disassemble the fuel system in the next few weeks, you're welcome to take a look.

on a similiar topic.. when you guys have put webbers in. what have you done with the cam breathers. I've gone and hacked the old airbox to fit the webber but im thinking of drilling some holes in the bottom of the proper air cleaner for the webber and fitting them there with some garden fittings. Would there be any major problems with this?

Should hook up well to that white garden hose that was in there Matt !

hehe

well i have removed the white garden hose ... but its just my dodgy ass hacking of the standard air filter that worries me . (i attached it with silicon).

Come have a look at my Weber some time Matt. The vaccuum system is all hooked up right.

Dave are you running the breather box in the rear of the hatch? That is, the little plastic box that sits behind the trim on the driver's side?

in regards to your fuel tank pressurising 1st id be checking fuel pressure what sort of reg are you using if its after market it should be adjustable. Should be 40psi also check your return line etc and filter you might even have a restriction there causing the problem.

There is no blockages or problems with the system... it has been checked and re-checked. Yes it still has the factory air-fuel seperator Tim which does appear to be working.

According to the 4 different Subaru manuals i have read the carbon canister is used to let fuel gasses that have been built up in the fuel tank into it for filtering... then lets the fuel particles into the engine and realeses the clean air. The fuel tank cap is used only to releive vacume in the fuel tank.

I have no idea why i have this problem... but this will fix it. Probbaly some weird import thing.

Dave

waggaclint wrote:in regards to your fuel tank pressurising 1st id be checking fuel pressure what sort of reg are you using if its after market it should be adjustable. Should be 40psi also check your return line etc and filter you might even have a restriction there causing the problem.

Should there be any sort of restriction at all on the return line or should you be able to blow through it with you mouth?

I forgot to add that the regulator im using is the factory one on the ej22.

Dave

are you running a surge tank if not you should and if you are just check if its hooked correctly. there should be four hoses on the the tank a feed from the tank one for the return one for the pre-pump and one going to the engine.The pressure is controlled on the return line.

Yes i do have a surge tank... yes it is hooked up right... i also added a 2nd return pipe into it in an attempt to fix the problem but i had no change.

Dave

I have this problem all sorted out and now understand what everything is doing. I will put up a diagram showing it all that will help people understand it and make it easier to addapt the EJ and EA systems. together.

Dave