Fuel pump, fuel lines, fuel pressure ?

[ekstroemtj]

Just had the fuel pumps and the filter replaced. Car runs great, even the problem with the idle dip at stops went away. A was so happy but now.... I feel if the fuel level in the tank is going lower the car is acting strange again.

When i take the car from the shop we went for a xmas holiday. First 200 km great performance at any idle and any speed. No problem to hit 250 km/h. Very smooth at all. After about 1/2 tank i would say, suddenly again strange acting again. It feels like there is no fuel for some seconds. I was realy affraid something seriuos again. At lower speed i feel it even more than a higher speed. Any idea what could happen? I feel its in some way related to the last job at the fuel tank. But maybe i am wrong.

Cayenne S 2004

[ekstroemtj]

Update

Just drive with tank full. Same strange behaviour.

This car acts like a small child. Every day complaining about something else :-)

[bigbuzuki]

Here is a table showing the pump logics.

Starting procedure: left and right pumps on

Fuel tank qty >60 L

right pump on.

High load: left and right pumps on.

Fuel tank qty < 60 L

left pump on.

High load: left and right pumps on.

Did you also change the fuel regulator with the pumps and filter?

[ekstroemtj]

Thank you for explaining me how the system works.

About the Part which you mentioned ....... Where is it located?

Regarding the invoice of the Last Job i can Only see:

Right pump replaced.

Filter replaced.

Left pump checked. Only replaced a wire Which was Not sitting correct.

Thank you

[bigbuzuki]

The fuel filter is located under the left access cover which gives access to the left fuel pump.

The fuel regulator is located under the right access cover which gives access to the right fuel pump.

There is plumbing that is disturbed when changing the pump and filter.

It possibly may be causing your issues if it has not been securely reconnected.

[ekstroemtj]

Thank you very much. We will check if this is the cause of the problem. Nice sunday

[deilenberger]

The fuel filter is located under the left access cover which gives access to the left fuel pump.The fuel regulator is located under the right access cover which gives access to the right fuel pump.There is plumbing that is disturbed when changing the pump and filter.It possibly may be causing your issues if it has not been securely reconnected.

Seems to be this month's theme on problems.. :help: