Still Battling EVAP Issue

[christianb5s4]

Got the car back and while it's running great, the few things I did to tackle the EVAP leak issue did not solve the problem. Here's what's been done:

- New EVAP purge valve
- New line and check valve to the purge valve
- New gas cap
- All lines on the engine side inspected and tested for leaks
- New PCV, oil separator, etc.


Unfortunately the EVAP code came back, however here are a few symptoms in case this gives ya'll any ideas on what the cause might be. Codes that come back are always P0441 and P0455:

- It comes back as soon as the car gets down to a 1/4 tank of gas
- Still has a hard time starting after gassing up but the tank fills just fine so I don't think it's a charcoal canister issue
- Can smell gas strongly outside the car while filling the tank with gas, however no visible leaks

Did some more research and it's all pointing to the leak detection pump. Does anyone have feedback?

[SinCityA6]

I am having a similar issue. VCDS is registering a very small EVAP leak and every time I fill my tank, I smell gas fumes outside the car until the tank falls below 3/4. I’m thinking it is either the charcoal canister of the leak detection pump.


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[cal3thousand]

Gas cap could be causing those codes. How confident are you in the gas cap's condition?

[christianb5s4]

It has to be one of those two, the charcoal canister is easy enough to change since it's super easy to access in the back of the car but I am more worried about the leak detection pump due to where it's located. Forgot to mention but I also threw a brand new OEM gas cap as the first thing I tried, which didn't do a thing of course since that would be too easy. *sarcasm*

[SinCityA6]

Gas cap could be causing those codes. How confident are you in the gas cap's condition?

For me, the gas cap was the first thing I swapped out. No change.


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[snowzach]

I had the code and played with some of the solenoids. I replaced the one under the rings cover with a short "S" shaped hose. The Oring was really old and didn't seal well. There was also dust in the hole. I replace the solenoid and smeared some thick bearing grease in the hole to help it seal. That fixed mine. I don't know if that's the evap solenoid but it was the one causing my issue...

More importantly did the PCV replacement fix oil consumption problems?

[christianb5s4]

Too soon to tell on the oil consumption, granted I didn't measure consumption before it was replaced so I can't tell you what change it made. After a bit more time I'll let you know if I have an issue or not!

I replaced the EVAP valve with a brand new OE part from the deal which is this one as well as the breather hose that connects to that valve which has an integrated check valve:




However the reason I believe it's either the leak detection pump and/or the charcoal canister is because the system on block 070 passes the test when the tank is 1/2-full but the codes come back as the tank gets lower, the hard start after filling up as well as smelling fuel vapors while pumping the gas also remained. However I do not have issues with the pump stopping and fills normally.

[snowzach]

Yah, that's the one I replaced that fixed my problem. Sorry man good luck hope you solve it. Report back on oil consumption if you could. That's one I want to tackle this summer.

[christianb5s4]

That EVAP valve and line fixed the sporadic flow code I had, but the large leak codes remained although they don't come back as quickly. Does anyone have a guide, pictures or DIYs related to the leak detection pump on these cars by chance?

[christianb5s4]

So I replaced the whole leak detection pump assembly and checked all the lines related to that, the charcoal canister and the lines around the filler neck. Smoke tested and could not find any leaks but the car still has the following codes:

P0441: EVAP Emission Control Sys: Incorrect Flow
P0455: EVAP System: Large Leak Detected

Things I've done so far:

- New purge/N80 valve
- New breather hose and check valve
- New leak detection pump assembly

I can still smell gas after filling up and the car takes one or two tries to start after fill up. Anyone have any other leads on what to look at next?

[christianb5s4]

Any ideas? Otherwise I'm going to take it back to the shop and have them deal with it.

[11A6]

I've got nothing to add - curious as to the resolution.

[itsmatt33]

Random question, do you have an aftermarket stereo or sub installed? check where the ground was drilled in.

[christianb5s4]

The biggest clue I have is that I can smell gas when I pump the car up, I smoke tested the lines at the filler neck area but didn't find leaks. I'm guessing it's the charcoal canister but I want to find a way to test it first before dropping $250 on it.

[ichi d]

Don't have much to add but did u try and change your fuel filter?

[christianb5s4]

I have not replaced it, I can't imagine it's too much harder to do than my B5 S4 though. I'm also going to inspect the fuel pump assembly as I found a thread about someone who had a leak there that could be a source of an evap leak.

[christianb5s4]

https://www.audiworld.com/how-tos/a/...-filter-422174

[christianb5s4]

Progess: installed a new OEM charcoal canister last night, smoke tested all the lines at the back of the car and found no leaks. First thing I did was go to the gas station and fill the tank to see if the car had a hard start. It did, however for the first time since I bought it it actually stayed running instead of starting then stalling then having to restart it again.

The bigger learning is I pinpointed the area where the gas smell is coming from which is the front passenger side fender and/or engine intake area. Just smell which goes away quickly, no visible leaks. What lines are in that area that are fuel or evap related?

[cal3thousand]

Progess: installed a new OEM charcoal canister last night, smoke tested all the lines at the back of the car and found no leaks. First thing I did was go to the gas station and fill the tank to see if the car had a hard start. It did, however for the first time since I bought it it actually stayed running instead of starting then stalling then having to restart it again.

The bigger learning is I pinpointed the area where the gas smell is coming from which is the front passenger side fender and/or engine intake area. Just smell which goes away quickly, no visible leaks. What lines are in that area that are fuel or evap related?

The HPFP is run off the passenger side intake cam lobe. The hard line runs from there to the SC valley and to the injectors. Maybe you have an injector leak or pump leak? (not sure how that would affect EVAP codes... just a guess at the moment)

[christianb5s4]

No injector leaks, those all have brand new seals after doing the oil separator/PCV line/thermostat. Smell does not come from the intake valley, only from the passenger wheel well area.

[christianb5s4]

I narrowed down where the gas smell was coming from, it's where the two hoses that lead from the HPFP and the vent tube from the intake meet the hard-line. I filled the car with gas and as the tank was filling, I could smell fuel vapors from the area the arrow is pointing to. I replaced the hoses and both clamps that lead to the intake but the large leak code came back. I'm going to replace the other hose as well.

To note, the only time there's ever a fuel smell is when there's gas being pumped into the tank and the vapor smell only comes from this specific location.

[christianb5s4]

Alright everyone, so I've had the EVAP smoke tested and these two codes are really stumping myself and mechanics I've brought it to. Still gets the same P0455 and P0441 codes. Anyone have ideas? There are no bad ideas at this point. To recap I've done the following:

- New OEM gas cap
- Smoke test all lines
- New purge valve and purge valve line w/ check valve
- New leak detection pump
- New charcoal canister
- New fuel filter
- All SAI and fuel lines inspected and leak free

[juniorcruzer]

were you able to confirm that the SAI line under the supercharger is leak free....that one would be impossible to inspect unless you took the supercharger off.

[christianb5s4]

IIRC that line goes from the purge valve to a port under the supercharger and has a check valve built in? If so I had it replaced with a brand new line already, should be this line: https://www.ecstuning.com/b-genuine-...e/06e103207am/

Spent a few hours at the shop where they traced every EVAP line and smoke tested all of them and no leaks. However, I've noticed this odd noise coming from what I believe is the HPFP for a while and think it's related. After a drive and the car is fully up to temperature then shutting it off, there's this periodic pressure relief sound from the HPFP for a little while until the motor cools off. Is it possible for the HPFP to have an internal leak?

I took a video of it and have pressed my ear to it and pinpointed the sound which without doubt is coming from this region. It's very faint in the video but at 6-7 seconds you can hear it if you turn the volume up.

[christianb5s4]

Another reason I believe it's the HPFP is because my 800 mile old oil has a distinct fuel smell to it. I'm ordering a new one since it seems easy enough to DIY.

[christianb5s4]

Does anyone know the specific location of this solenoid valve?https://www.ecstuning.com/b-genuine-...ch/037906283c/

Here's the diagram of our 3.0T motor and vacuum lines and shows this solenoid being the part #6 in this picture.

[juniorcruzer]

which number 6? there are two on top, and one down in the middle?

Jon

[christianb5s4]

The one down in the middle specifically.

[juniorcruzer]

I will try to get a look at my car today and see if I can follow it to where it goes. As much as I have been under the hood lately, it is not apparent to me where it is from the drawing.

[christianb5s4]

Thankfully I can say this has been finally solved. I had the high pressure fuel pump replaced as there was some evidence it was leaking oil slightly and leaking internally. At the same time, all EVAP lines were double checked and verified there's not a single leak. So we went back to the basics, checking out stock Audi photos of the C6 3.0T engine bay and discovered the cause.

The EVAP line that should connect to the purge valve was connected to the intake and the PCV line that should connect to the intake was connected to the purge valve. Doh. Whoever worked on the car prior to my ownership put them on the wrong way around. No codes at all, car runs and starts smoother, power is more linear, gas mileage is up and I filled the tank and had no issues starting after fill-up.

[ichi d]

Thankfully I can say this has been finally solved. I had the high pressure fuel pump replaced as there was some evidence it was leaking oil slightly and leaking internally. At the same time, all EVAP lines were double checked and verified there's not a single leak. So we went back to the basics, checking out stock Audi photos of the C6 3.0T engine bay and discovered the cause.

The EVAP line that should connect to the purge valve was connected to the intake and the PCV line that should connect to the intake was connected to the purge valve. Doh. Whoever worked on the car prior to my ownership put them on the wrong way around. No codes at all, car runs and starts smoother, power is more linear, gas mileage is up and I filled the tank and had no issues starting after fill-up.

glad you figured it out. now tune it and enjoy this car!!

[christianb5s4]

Ok, so we are back to this issue unfortunately. Although I've been sporadically getting a new EVAP code which is:

001110 - EVAP System
P0456 - 001 - Very Small Leak Detected - Intermittent

Are there any check valves, purge valves or lines I should look at specifically? I think this is related to the lean codes the car has had.

[CrzyAznKB]

Had this on my car a few months ago. There is a TSB for ECM software update to rectify an issue causing P0456 when there is no leak present. Performed the software update and haven’t had it return since.

[christianb5s4]

That's interesting, do you have the TSB on-hand or have a link? I still have the lean codes which could be due to the crap VVT cover job the PO did (which is leaking), all EVAP and vacuum lines have been pressure and smoke tested multiple times.

This is the first time the EVAP small leak code has come up, the original EVAP problem has been fixed already (P0441 and P0455).

This solenoid is the only other thing that hasn't been replaced yet EVAP related: https://www.ecstuning.com/b-genuine-...ch/037906283c/

[CrzyAznKB]

2022824/7 is the TSB. For 09, the updated ECM software level is 080 or higher. If you have a scan tool you can check that.

[christianb5s4]

Thank you, I will check that out! Wanted to have the dealer update the ECM software anyway.

[christianb5s4]

Had the ECU updated at the same time as having the airbag recall done, latest software is on the car and so far so good.

[christianb5s4]

I'm still battling a persistent P0456 and have the latest ECU software, replaced the purge valve, leak detection pump, Kombi valves, vacuum pump, hoses, OEM gas cap, charcoal canister, smoke tested EVAP lines, etc. Car has nothing else wrong and runs great.

The car continues to get the P0456 despite all that, is there anything left I can look for? About ready to bring it to the dealership at this point but that's a last option.

[B. Rock]

I have no idea, but noticed that you started this thread about a year ago. That has to be frustrating.

[christianb5s4]

It doesn't affect the car's performance fortunately, I just hate knowing there's a code and eventual CEL. Been trying to do some sleuthing on the forums but there are some key differences with the EVAP and vacuum systems on our cars versus the 3.0T in the C7s and others so it's not apples to apples.