Fuel pump prime when drivers' door opened?

[gillm]

yep thats how they work , infact most vag cars do if not all

[ub7rm]

^ as above, all the VAG cars I've been in do this and its noticeable.  My mk4 GTI did it, my wifes 1.2 polo does it and my 05 GTI does it.

[john_o]

afaik its also in the service manuals as a warning to avoid triggering it while working on the fuel pump

[john87]

well for some reason mines doesn't do it. The hire car (seat ibiza) I had last week did it..

just to be sure, I'm gonna lift the back seat tomorrow and listen at the pump while I get someone to turn the key, as it's supposed to do a further 'blip' of the pump after the initial door-open priming. If I hear nothing, I'll be sure to mention it at service time, next month 

[ub7rm]

I wouldn't have thought the car would run at all if the pump wasn't working and there would certainly be fault codes...

[vwrascal]

I hear the it prime, like a quiet 'whine'! Have cold start problems occasionally 

[Teutonic_Tamer]

How obvious is this sound? I could hear it quite clearly on the Ibiza, a sound like water passing through a kinked section of garden hose, for about a second or two. Nothing in the GTI though 

Maybe the Ibiza (being a cheaper make - dons nomex suit  ) has less soundproofing than VWs . . . .

[Teutonic_Tamer]

I have a hunch that I'm on to something here...

Be careful when you get off it then! 

I've had cold start problems ever since I've had my GTI, where the engine stutters then finally fires up...sounds like a bubble of air going through the fuel lines.

I'd be curious to find out if all those who can hear the in-tank pump priming have ever experienced this delayed cold start issue?

My GTI occasionally stutters or hesitates on startup (usually when its been left for more than a day or two) - but I always hear the fuel pump prime when I open the drivers door.  I also hear it do the same on my RS4 - and that is the same - starts instantly when used regularly, but if it hasn't been used for a fortnight or more, the starter can sometimes crank for about six seconds before the beast awakens.

Try removing the rear seat squab - because the low pressure lift pump is basically under the rear right seat - and then see  if you can hear it.  Or how about trying a 'double prime' - unlock the car, open drivers door, shut door, open drivers door again . . . and see what that does.

Personally, I'm not convinced at all that the low pressure lift pump is the problem - this does NOT provide the necessary pressure to activate the injectors.  The electric lift pump is designed to pressurise the fuel lines to 6bar, whereas the mechanical HPFP will give around 110bar - and it is this 100+ bar figure which is needed by the FSI system.  If your lecky low pressure lift pump didn't work, then it is doubtful your engine would run at all.

Finally, the electric low pressure lift pump is DTC enabled - it will log and store fault codes - so scan your car with VCDS.