Carbon Canister Removal Doc For Checking

[Vimmy]

Hi Guys, I've seen a few threads about removing the carbon canister. Having wanted to do it myself to stop them nasty vapours getting back into the air intake I went through all the pdf's and other docs I have to make some sense of it all and have documented it below. It should apply to most Imprezas, although I can only verify this for mine.

If anyone has a few minutes to spare could they check over my ramblings, I think I have it right and wanted to give something back to the forums in the way of helpful diagrams/how-to's etc.

Anyhoo here goes:

Break A: EVAP Line - from fuel tank to be passed into the canister and purged

(1)Remove short hose from the two way valve to the canister

(2)Reattach this to the evaporation line where it comes into the engine bay and vent via another rubber hose (to atmosphere) under the bottom of the engine bay.

The evap line is one of the three lines next to the fuel filter. Two of these lines (fuel in from filter and fuel return to tank) have jubilee clips holding them on, the 3rd (evap line) has a small push clamp as it is under less pressure than the fuel line pressure.

Break B: Throttle Body Line - where Purge Control Solenoid Valve has opened under ecu control to allow TB intake vacuum/pressure to pull tank vapour through from canister.

Remove the rubber hose from the throttle body (#2) that goes to the Purge Control Solenoid Valve(#3) (under right hand side of Inlet manifold) then place a plug/bung onto throttle body (where hose had been) to stop leaks to and from the throttle body.

Break C: Canister to Purge Control Solenoid Valve line - where tank vapour is pulled out of the canister under ecu control to the Throttle Body

Remove the rubber hose from the hard line (which is the other end of the Purge Control Solenoid Valve) to the canister. The other rubber hose at the far end is still place but serves no purpose. B above has removed the other PCSV hose prior to this.

Break D: Aux Purge Control Valve - where canister vapour feeds into cold air intake pipe (between turbo inlet pipe and MAF)

Remove the rubber line from the APCV to the air intake pipe and plug the hole in the air intake pipe.

Reference Info: Pressure Sensor #4

The pressure sensor alternately receives the intake pressure in the intake manifold/collector chamber and the atmospheric pressure pressure and converts the pressure values into signals and sends these to the ecu. The atmospheric pressure is measured by this device, the intake pressure is received downstream from the Pressure Sources Switching Solenoid Valve.

Reference Info: Pressure Sources Switching Solenoid Valve #5

The PSSSV switches the intake air pressure from the intake manifold/collector chamber to the pressure sensor under ecu control, when off the pressure sensor only reads local measured atmospheric pressure.

Reference Info: Valve / T-Piece

The Pressure Sources Switching Solenoid Valve #5 is shown (lifted from the Subaru maintenance diagrams - Inlet manifold connections) at point F to read intake pressures at the collection chamber, however, after mapping the various pipes and fittings in my car this PSSSV is connected via some kind of 1 way valve (H) to a small plastic T piece (G). The second hose off the T piece carries on to the inlet manifold/collection chamber (F) as normal. This third hose off the T piece now connects to the Aux Purge Control Valve (E). I have to assume that at this point that as the car is running along there is positive pressure in the collection chamber and this pressure (in the direction from F to E )forces the Aux Purge Control Valve open to allow vapour to be sucked through from the canister to the air intake pipe.

Break E: Aux Purge Control Valve to T piece

Remove the rubber hose from the middle port of the plastic T piece (E) that connects to the smaller diameter connector on the Aux Purge Control Valve. Plug up the now opened centre T piece (E) to remove any pressure/vacuum leaks. This should leave the Pressure Sources Switching Solenoid Valve connected via the two opposing legs of the T piece to the inlet manifold/collection chamber.

Thats about it, fairly straight forward I don't like doing stuff to the car unless I understand what I should be doing, although that hasnt stopped me before

Thanks for taking the time to read this,

Cheers,

Col

PS piccy below

[Big 'D']

Hi Col

Good work mate it all looks good to me, just be sure that the tank vent/breather line is vented well away from any heat/ignition source and you could add a filter on the end ie a plastic in line fuel filter.

Cheers Iain

[Vimmy]

Thanks for having a look Iain, much appreciated Would I get away with using a small air filter type thing like the ones used when you vent the cam covers to atmosphere or is that the wrong thing? Would one of these be a better option?

Cheers,

Col

Edited March 17, 2010 by Vimmy

[Big 'D']

Thanks for having a look Iain, much appreciated Would I get away with using a small air filter type thing like the ones used when you vent the cam covers to atmosphere or is that the wrong thing? Would one of these be a better option?

Cheers,

Col

Any vent/fuel filter would probably work to be honest mate.

Cheers Iain