3.6 CC. Cranking but not starting

[seanmau5]

Mine fires up if I pump the accelerator too, but unfortunately (or fortunately, depending on how you look at it) I’m not the kind of person that can just live with an issue like this. No I didn’t do a scan while it was running rough like that, because while I had the cord that I had borrowed, the stupid car wouldn’t do it. The day after I return it and bingo [emoji849][emoji849] I’ve not used any of the foam cleaner before, but I did just buy a can of liquimoly that I’ll run through it this afternoon and then on Thursday I’ll remove the intake and inspect. I find it so odd that it’s only when it’s hot outside and based on the research I’ve done, this is a common issue that I refuse to pay VW a diagnostic fee to tell me there is ‘nothing wrong’


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[00100100]

Any updates on the situation?

[seanmau5]

Sort of. I definitely think it’s an evap or tank venting issue based on all my situational testing.

Plenty of warm days, I’ve left the fuel filler cap loose so it doesn’t create a seal and the car starts first time, every time. Also, check out this link. On warm days only with the fuel filler cap sealed this happens. Release fuel filler cap and noise stops.

YouTube

[seanmau5]

Spent a bit more time on this today.. Particularly focusing on the charcoal canister.

The venting noise in the video in the above post is coming from the pressure retention valve which connects the tank breather line to the charcoal canister. This isn’t an electronic valve hence no errors - I believe it works based on pressure and has a diaphragm in it that allows air flow dependant on this pressure. There are 2 soft rubber o-rings and one harder plastic o-ring inside the valve that don’t seem to be sealing properly and allowing air to be sucked into the canister past the seals and causing the noise.

Unfortunately I don’t believe I am any closer to solving the no start issue..

[00100100]

It is very odd indeed! Best of luck.

[Bozfromoz]

I have a similar issue with a golf mk4 that I just bought to play with. It definitely sounds like you have spark so most likely it’s your fuel delivery. You said low pressure had been found. I would suggest on a day that you can’t start it grab some 8$ starting fluid from Supercheap Auto and spray into to air intake. This should start it. Check for any leaks in the fueling lines , Check voltage on fuel pump. Then check fuel filter. Finally check injectors. You can do this test with obdeleven. It sucks if it’s your daily driver but if it’s not it can be fun !!!!!

[seanmau5]

So this has now thrown a CEL and my fuel use is nowhere near as efficient as the 11L/100kms that the display reads. Certainly using a lot more fuel than the average would suggest. I’ve had no starting issues for months because I’ve simply left the fuel filler cap loose. I’m going to buy one of those $40 charcoal canisters off eBay and put that in and a new genuine n80 valve.


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