Charcoal Canister Delete VCDS?

[aaronk.juju]

So I want to get rid of the charcoal canister so that I can fit a large catch can in its place. I've found a few threads about people deleting but havn't found a DIY. If I were to remove it and vent the line to the wheel well or somewhere similar, what would I do with the N80 purge valve and any associated CEL lights? Can you get around this using VCDS?

[Dan_FR]

Leave it as it is and scrap the catch can idea. They cause more problems than they solve.

VCDS will not remove the EML you will get or restore the fuel trim correction you will lose by ripping out the charcoal filter and associated parts. Only way round it is as part of a remap by someone who knows what they are doing.

Seriously, scrap the catch can and spend the money on a brand new original PCV

[pudding]

These engines have a catch can as standard, which is part of the oil filter housing......but it's a properly designed one that doesn't need emptying 

All catch cans do is fill up with brown stinky water.  They catch way less oil than you'd think, as Dan said, the money is better spent elsewhere.

If you leave the N80 valve plugged in, the ECU will be happy, but you will probably get "EVAP Purge valve incorrect flow" fault codes because it's expecting to see a fluctuation in the air fuel ratio when the valve opens.

[Dan_FR]

You get the EML and the code with just the N80 plugged in. Tried it... Cannot remember if the trims still worked though

There is a way of working around it to keep the EML away and keep it all happy but it is not worth it unless you plan to get it mapped out properly

[pudding]

On my R32 I had the secondary air injection pump and N80 coded out - as in "Hey ECU, don't bother with these routines", but the SAI relay and N80 needed to be physically plugged in otherwise you'd get no trims.   Haven't tried it on the TFSI but wouldn't be surprised if it's the same!

[aaronk.juju]

Funnily enough I have a PCV valve I just got due to a recent issue and was contemplating putting it back on rather than the delete plate or catch can. I think after your advice I'll revert back to the stock system 

[pudding]

Deletes are worse than catch cans, but yeah, get the stock parts back on 

[PGDO]

Deletes are worse than catch cans, but yeah, get the stock parts back on 

Just curious, what is the problem with a delete?

[rich83]

Well... why would you want to delete it?

[PGDO]

Well... why would you want to delete it?

Yes why indeed 
- Bought one because there was a 25% discount
- Because sometimes when your away from home for a long time you just need to buy something
- Because of reading the wrong forum threads first, mainly about PCV breakdowns
- Because it comes with a option to connect my new boost gauge
- Because it prevents oil mist to enter the engine via the intake manifold, less carbon deposits on the intake valves

So now I actually don't know if I should install it, only valid reason might be the last one mentioned but there might be more reasons to stick with the PCV.

[pudding]

Deletes are worse than catch cans, but yeah, get the stock parts back on 

Just curious, what is the problem with a delete?

It's a bit long and boring to explain but the key points are:

- The evaporative emissions control is like the Gestapo.  If it's not 100% sealed from petrol tank to intake manifold, the ECU bungs the EML on and stops adjusting the long term fuel trims.

- Removing or blocking the PCV outlets can actually reduce the engine's ability to dump it's crank case pressure, which is baaaaaaad on a turbo engine, especially when blocking the front PCV completely and just dangling a pipe from the rear PCV down the chassis leg to atmosphere.  That is also an instant MOT fail, not to mention fumes getting into the cabin.  A fully functional PCV system actually helps create a vacuum under the pistons to help 'suck' the rings on the bores for better oil scraping.  Not getting rid of that pressure can also cause rear main seal failure.....which is VERY common on remapped EA888 engines with aftermarket PCV mods.

In all honesty, the OEM PCV system offers more benefits than negatives.....in spite of what you may think when looking at those hideously caked up intake valves!  It's actually a pretty complicated setup and most people end up refitting it after getting pissed off with blue smoke blasting out of the exhaust.

As for oil mist clogging up the intercooler and intake valves, it's a bit of an exaggerated issue.  The main cause of intake valve fouling is oil dripping down from the valve guides being baked on by exhaust reversion and heat.  Oil mist from the PCV system contributes a very small part to the problem.  Even with a catch can or full front PCV delete, the intake valves will be black and carbon fouled again within 5-10k miles.  Most people, myself included, noticed nothing after a walnut blast.....but it's just something that needs doing every 50-60K, because......direct injection!

[PGDO]

Thanks Pudding for the clear explanation, wasn't bored at all 

[pudding]

Glad you didn't fall asleep 

I've been there in the past with deleted PCVs and just a rubber hose dangling down behind the engine block.  It stinks, it fails the MOT and the crank case pressure relief is less than half what it should be.  Oil and gloopy brown residue also drip out of said pipe onto things, including drives......not good if you have expensive block paving.

That was on older port injected engines, but when I got my GTI, I took one look at the PCV system and considered it too complex and tightly integrated into the engine's operation to mess with it 

The direct injection intake valve fouling is only an issue when it gets so bad it causes cold misfires.....but that's pretty rare.  With a turbo, the air will find it's way past any minor restriction no trouble at all.  You will barely notice anything after a walnut blast!  It's just naturally aspirated DI that's and issue in that respect.  Mine's on 145K and it's had one walnut blast in it's life.  Didn't notice anything.  Yes seeing clean valves is good for peace of mind, but in reality it really makes minimal difference, hence why DI engine manufacturers have never really pursued any kind of retrospective fixes....and they just don't care anyway after you've bought the car