Evap line

[Dunkdafunk]

Hi

I've had a look on some posts. Just need to clarify. I'm getting a large vacuum from the tank when opening the petrol cap. Its a 2006 bwa golf. Ive replaced the purge valve with a bosch. Works fine. No codes. I can blow air through into the canister from the purge valve line. But the line from the canister has a weird filter ontop, and its connected to a white plastic hard line which I assume goes to the tank and act's as an air line?

How does the black connector which goes to the charcoal canister come off the fixed hard white tubing which connects to the tank? And if i open the petrol cap, should I be able to suck air through this line easily?

Dunk

[pudding]

If you mean you get a whoosh sound when you unscrew the petrol cap (with less than 1/4 tank remaining), that's normal.  It means the evap circuit is sealed as it should be.

The carbon can's black rigid hardline > white hard line is the petrol tank's vapour/expansion outlet which is the carbon can's intake, and it's outlet is the rubber hose that feeds into the N80 solenoid.

No idea what you're going on about tbh.  The pressure release when undoing the fuel cap is the answer.  If you hear that, it's working as it should.

Anything not working correctly with the carbon can will throw a "Evap emissions - incorrect flow" fault code.

[Dunkdafunk]

The vaccum is so strong on a 1/4 or 1/2 tank it causes the lpfp to struggle if left. However Full tank it works fine. No vaccum. No codes.

Recently done new lpfp. New fuel filter. New lpfp relay. New lpfp regulator. And adaptation test on vag com seem fine. This set-up has worked fine for the last 6 months. No large vaccum.

How does the tank introduce new air when the fuel gets used? I thought the evap line draws air out of the tank? How come it does this at 1/4 of tank?

The n80 works fine. I can look on block 70 vagcom and I can see % open being used. Oxygen sensor control % is always 0.

In terms of the pipe which goes from the canister to the fixed hardline im not sure how the connector works. EDIT. Ive found that this is a speed fitting like the one found on the fuel filter with the tabs.

[ROH ECHT]

The leak detection pump pressurizes it all to detect pressure contained as well as pressure drops. It generally codes when failing though.

This is likely the best VW EVAP system description; https://blog.fcpeuro.com/heres-how-a-volkswagen-audi-evap-system-works

[Dunkdafunk]

Interesting. Never seen an evap leak detection pump. It is housed with the fuel tank? Il have a read of the link. Noticed that it relies on engine temp. And I think my thermostat may be dodgy, since it takes a while to sit at 90

[ROH ECHT]

It's behind the rear arch liner near the fuel filler neck. Rear side of the arch.

On the topic of the thermostat...You may need a replacement. I just replaced mine. The temp was taking longer to reach normal operating temps. When I watched the gauge the temp would almost get there and then drop a bit before finally, after more time, reaching normal temp.

[Dunkdafunk]

Cheers. They seem quite pricy on ebay  1K0 906 201 C 
Il have a look under the arch tomoz.

How long did it take you to do the thermostat? Easy enough to do? Any tips?

I think I read somewhere that it should hit 90deg on idle in a short amount of time, like 5 min from cold or somethin. And when driving it should be at 90. Mine takes ages to get to 90, never really stays there for long either. But I only noticed it through having oil sludge in jan/Feb, and higher oil consumption, so i kept checking the engine temp.

[ROH ECHT]

Cheers. They seem quite pricy on ebay  1K0 906 201 C 
Il have a look under the arch tomoz.

How long did it take you to do the thermostat? Easy enough to do? Any tips?

I think I read somewhere that it should hit 90deg on idle in a short amount of time, like 5 min from cold or somethin. And when driving it should be at 90. Mine takes ages to get to 90, never really stays there for long either. But I only noticed it through having oil sludge in jan/Feb, and higher oil consumption, so i kept checking the engine temp.

Yeah...pretty sure your thermo is stuck open and opening too soon. I didn't just do the thermo so everything was removed on mine because I did a new oil filter housing/assembly, the thermo, positive cable for the battery, and injectors. So I was removing most of it. To only get at the thermo, you can try watching this "watch me work" guy. He adds notes, but I wish he would talk, LOL;

[Dunkdafunk]

Cheers RON ECHT

I lifted the rear near offside arch but couldnt find the evap pump.

After letting the car warm up to 90 deg, and trying to keep it there with higher revs, I found the tank much better to manage vaccum. So it does seem that the evap system needs the thermostat to be working properly.

I've done the thermostat today. Followed the video. Thanks mate. Yeh i noticed how silent the video was lol.

Couple of tips for anyone who wants to do the thermostat on a tfsi bwa.

Use a flexible long reach locking hose clamp. Awesome tool.
Have ready some pilot bits to line up the alternator holes.
Have ready the right size locking pin for the belt tensioner. 3mm Allen key will do. Might be good time to replace old belts.

Large vaccum in tank seems much better.

[ROH ECHT]

You removed the arch liner where the fuel filler neck is and no leak detection pump was found? It should be tucked up near the filler neck;

Yeah, many of the guy's vids he says nothing, and some he does talk.

[Dunkdafunk]

Thanks for the leak detection pump vid. Yeh I've got a 2006 bwa golf mk5 and there's not a pump there. Must be a different set-up? The thermostat now stays at 90 all the time once warm. Seems to have sorted the large vaccum

[ROH ECHT]

Yeah, must be different. I'm sure it has one...as the white tube you mentioned should go to it. But where is it?, is the question.  Good news on the temps though.