2 replies to this topic

[jamesy]

Can the Charcoal canister be done away with on my Spi? starting to put my car back together, and was wondering if its really necessary and could be done away with? (not even 100% sure how it works or what it does!)

[spiguy]

Not sure, I suppose in theory you could just leave the pipe open - it is to provide a vent for the tank. On older minis, there was just a pipe which ran down through a hole in the boot floor. The charcoal canister is plumbed in to the inlet manifold via a purge valve (mounted on the passenger side inner wing / bulkhead area. The way it is supposed to work is that fumes from the tank are vented to the canister (I think there is a pressure activated valve on top of the tank - I know on a hot day I hear the gasses making a squeaking noise in the tank as they pass through it) then the purge valve is opened by the ECU under certain driving conditions, as far as I know it opens the purge valve when the engine is hot and you are cruising at some particular engine revs.

 

The idea behind all this is to stop petrol vapour being vented to atmoshpere, for environmental reasons - by feeding it back to the engine via the canister, you basically burn off any vapours in the engine rather than just venting them.

 

If you remove it, you need to still vent the tank. If you just remove it, then you will effectively be venting under the passenger wing - not sure if that is ideal. As I say, I suppose you could just run a rubber pipe down through the boot floor like it used to be? 

 

The other thing to consider is that if you don't do anything other than remove the canister, then when the purge valve opens it will create a vacuum leak for a short time. Might be inconsequential, but I would think you would be better to disconnect the electrical connector from the purge valve to stop this happening.

 

I would say unless it is broken, or there is some other good reason to want to remove it, just leave it in place.

Edited by spiguy, 24 February 2016 - 10:40 AM.

[jamesy]

I see, Thats the kind of informative answer i was after, cheers! 

 

I have a completely bare shell at the moment, and in the process of building it back up, was just trying to do away with any unnesessary rust traps, seeing as it probably is necessary, and the ecu may take a hissy-fit i will give it a good clean up, and get it all re fitted if i can remember how it was all plumbed! haha!