EVAP Purge flow

[Polecalex]

Hello,

I've got a Leon Cupra MK3 2015 that has been stage 1 mapped with a custom sports catback and it's currently failing it's MOT due to high CO, HC on the second fast idle test.

Currently it has two codes (removed), P001100 and P044100 which I have known about for a while now. Talking to the MOT mechanic, he said my Cat has gone after 2 years which is why it's failing the test, best option is to replace the centre pipe with a temporary cat to pass MOT. The mechanic who made my exhaust has said the cat should be fine and since it failed on a lambda sensor it's probably a leak with the exhaust or intake (reluctant to say exhaust since it's stainless steel). He's suggested to repair the evap canister and valve before paying stupid money.

I'm going to go with fixing the evap system since this seems to make more sense as it passed last year without this code but I don't want to spend the estimated 2k from the MOT mechanic. Looking to do this myself but struggling to find any information and locations on the evap as it's all for MK2s or Audi's.

Does anyone know where the evap canister is located? I've heard it's in the engine bay, but also heard it's behind the nearside wheel arch. Also a part number would be great since I cannot find anything online.

Worst part of fixing your car yourself besides rusted bolts is finding the correct part and it actually fitting because you've bought part number 112233A but instead you needed 112233B.

Any help is appreciated!

 

[tracktoy]

This is from the fuel system workshop manual

 

[Polecalex]

This is from the fuel system workshop manual

View attachment 51726

That's really useful thank you, does it mention any part numbers? Otherwise, I'll follow instructions and have a look for myself tomorrow.

 

[tracktoy]

The part number I have is 5Q0201801 and I got it from https://seat.7zap.com/en/europe/leon-typ-5f-parts-catalog/#group=3 but don't know if that site is still being updated. If you are going to remove the canister I would have a look at the full workshop manual, you can find a link in the Guides section for the MK3

I had issues with the valve in the engine compartment, purchased a used one of ebay and it did not solve the issue. My local VAG Specialist got me a new one and the issue cleared. It is worth (on the valve) doing an output test, you can hear the valve working (although my duff one said it was working).

 

[Polecalex]

The part number I have is 5Q0201801 and I got it from https://seat.7zap.com/en/europe/leon-typ-5f-parts-catalog/#group=3 but don't know if that site is still being updated. If you are going to remove the canister I would have a look at the full workshop manual, you can find a link in the Guides section for the MK3

I had issues with the valve in the engine compartment, purchased a used one of ebay and it did not solve the issue. My local VAG Specialist got me a new one and the issue cleared. It is worth (on the valve) doing an output test, you can hear the valve working (although my duff one said it was working).

Seems to be the same as what I have been looking at, different prices everywhere though. Had a look at some of the guides and all I can find is what you've already sent so will just be a case of looking and dealing with what I've got.

I've had a look at the valve, ran a couple of output tests on it using my OBDEleven 2 (Had to use the older app since the newer just returns an error) but it sounds like it is working. Got a few patterns of clicking but not sure what clicking is correct. Sounds like a high pitch clicking in different patterns until it stops so I assume this is working alright. I will probably go ahead and replace both the canister and valve anyway just to be sure.

 

[nd-photo.nl]

@Polecalex the evap canister on my ST is located in the rear right wheel well. Peel of the arch liner and you have clear visibility

If the cat is gone after 2 years, I would suspect the quality of the tune (EGTs too high for instance).

 

[tracktoy]

I would also add there is more than one type of cat, A member on here CAT Failed (longer than two years) and when he went back to the Garage they confirmed they had fitted a cat designed for the Race Track not for road use and these just don't last as long.

 

[Polecalex]

@Polecalex the evap canister on my ST is located in the rear right wheel well. Peel of the arch liner and you have clear visibility

If the cat is gone after 2 years, I would suspect the quality of the tune (EGTs too high for instance).

I'll keep that in mind when I take it back for a re-test. All of this is of course speculation and it might well be that the cat has gone. I'm not using the car too much currently so it's not an urgent fix but ideally it's fixed with as little cost necessary so if the EVAP doesn't sort it I'll talk to the garage and look at either changing the cat or the tune.

I would also add there is more than one type of cat, A member on here CAT Failed (longer than two years) and when he went back to the Garage they confirmed they had fitted a cat designed for the Race Track not for road use and these just don't last as long.

That makes sense, I got the cat done on a whim so I'm not entirely sure on the details. I highly doubt it is a race cat since I didn't pay ridiculous amounts for it but with that being said, it probably wasn't the best quality either.

I appreciate the advice and will update this thread accordingly with any outcome. Will also potentially try to creating a guide for EVAP valve and canister replacement while I do this if there isn't already one (can't find any).

 

[tracktoy]

Well today OBD11 released a blog on this very issue (passing emmisions test)

check out https://forum.obdeleven.com/thread/45093/pass-emissions-test-tips-drivers?page=1&scrollTo=129519

One thing which i have heard of before make sure your engine is up to temp before dropping it off, cold engines can cause issues.

 

[Polecalex]

Well today OBD11 released a blog on this very issue (passing emmisions test)

check out https://forum.obdeleven.com/thread/45093/pass-emissions-test-tips-drivers?page=1&scrollTo=129519

One thing which i have heard of before make sure your engine is up to temp before dropping it off, cold engines can cause issues.

That is impeccable timing! When I ran a readiness check it only flagged an issue with VVT which I am aware and need to check the timing chain for any strain. I'll keep all of that in mind before going back but I'm probably going to try to test the VVT solenoid as it might be stuck? Sounded like it was working during a test but could be half retracting.

Thanks for all of this information, it's really helpful.

 

[tracktoy]

One last thing today the non vag app was updated to 1.37 and I had lots of issues when trying to read adaptions and long coding on 1.36 but 1.37 works much better so give that a try as well just to see if its better for you.

Good luck that its a simple cheap fix.