Whine at fuel cap. Air in system? 1996 A4 1.8se petrol non-turbo ADR auto

[warptechno]

Hi All,

Have been getting what can only be described as a whining noise coming from the fuel cap area when the car is running. Also a sort of 'gurgle' noise from around the fuel pipes just below drivers door.

Will be getting under there tommorrow when I have more time to investigate the pipes, but does anyone have any ideas? The car runs fine, no loss of power and doesn't seem to be losing fuel in any great amounts if at all. Where is the fuel pump located?

Cheers in advance as always. Car is in title.

[warptechno]

Having driven a few more times, the fuel gauge seems to drop really quickly once the car is up to optimum temperature. If you turn off the ignition and let it sit for a minute or two and start the car back up it seems to show the correct fuel level again. There is definately a strange noise amost like air releasing when you turn the ignition off though.

Any ideas anyone??? Don't want to shell out for a new fuel pump if it's not the root of the problem.

[green A8]

Has your car got air con fitted? That will make the noise you are describing when the ignition is turned off, nothing to worry about. The only time I've ever heard a gurgle type noise from the bulkhead area was on an A6 just before the PAS rack blew it's seals! So I hope that's not what you can hear. It might be wise to check the PAS fluid levels and for any signs of leakage.

As to the rest of your problems, I'm sorry I haven't got a clue. The only time I had a fuel pump stop working, that's exactly what it did. No warning, no strange noises. It (and the engine) just stopped! Not all that funny. I was doing about 70MPH (honest, Officer) on the Motorway at the time!

Sorry I can't be of more help. Perhaps someone else will add their opinions, and advice.

Kind Regards.

Paul.

[warptechno]

Cheers for the reply Paul. I know it can't be the air con as mine isn't working, (leaking from one of the seals!)

I know now that when the whining noise starts the fuel gauge starts to drop to empty. If I loosen the fuel cap then it sounds like air escaping and the whining noise stops. Does anyone have any ideas??? I've looked into posts discussing a faulty evap which can cause these symptoms. I ran a scan last night and nothing is logged in VCDS.

Has anyone had these problems or dealings with the EVAP? Don't want to be driving about with a fuel cap loosened off!!

Cheers guys

[warptechno]

UPDATE

So I had a good look at the EVAP yesterday and it certainly appeared to be working, had the car running for around 10 minutes to get the car up to temperature. EVAP making a ticking noise and sucking noise and fuel pump whine not evident.

Drove into work this morning (20 minute drive) and it has started again. Fuel level dropped on gauge in dash (due to the fuel tank collapsing I suspect) and whine from fuel pump and sucking noise from fuel cap. I popped the bonnet and it sounds like the EVAP had stopped functioning (no ticking noise). I disconnected the hose going into the EVAP from the fuel tank and the symptoms immediately stopped. When I reconnected the hose to the EVAP it started ticking again and everything sounded normal.

Am I right in thinking that a simple swap of the EVAP will sort this or is there a sensor which controls it at fault here. Clutching at straws at the minute, due to this problem not throwing up any fault codes on VCDS.

Anyone any ideas???? Cheers folks