2005 CS cannot idle

[Ricky1]

Here we go... after owning it for less than two months the CS cannot hold idle and stalls. It starts up properly then about 10 seconds later rpms slowly goes down and stalls. Battery seems to be good. I've started it for about 10 times (not in a row) and the starter sounds strong. If I rev it up to about 2500 rpm after starting it, again, after about 10 seconds the engine slowly stalls. It doesn't cut out right away.

Any ideas? Its sitting about 3 blocks from my house right now parked on a side street. Good thing its not farther away. Fuel filter? Fuel pump?

Seems like some of the electronics is wonky... when I start it there seems to be stuff moving around behind the dashboard, vent flaps or something and says my radio is off.

:blush: :blush: :blush:

[JFP in PA]

Could be a fuel pressure issue (the 2005 has an integrated fuel filter in the pump assembly, so it cannot be changed without doing the pump). Easy to test (there is a fuel pressure test port on one fuel rail that you hook a gauge up to for testing). I would get it flat bedded to somewhere where it can be tested.

[wvicary]

Sound like the primary (left) fuel pump is failing. As started, you'll need to test the fuel pressure of each pump independently.

[Ricky1]

Right side fuel pump was the problem says Porsche Service. Porsche strongly recommends changing both pumps even if one is still working. Says they never ever replaced only one pump before. Porsche also said my warranty company wasn't a good one since the warranty would only cover one pump and not both. Warranty contract says "fuel pump" not "fuel pumps" plural nor "fuel system".

Anyways, it has two new pumps and other stuff like a new regulator and filter. The Cayenne now is more reliable before this service along with a new fuel filter. The following photos are of the parts I requested I get back from the dealership... a "unusual request" from a Porsche owner according to them. Well one pump was still working, right? Anyways, here are photos of the fuel pumps and other parts. Something that I would have liked to see ahead of time myself. I also dismantled a fuel pump assembly down to the motor and impeller itself. There is a CZ site that is selling the motor and impeller for about 105 Euro.

All Parts

Top of pump assembly... has VW stampped on top

Bottom of Venturi Tube... has VW and Audi circles

Venturi Tube, again VW and Audi

One fuel pump assembly... individual parts

The pump itself with side opening for impeller.

ps. After moving the impeller with a small screwdriver and applying 12 volts to the pump that was at fault, the motor spun up and ran. It did not run smoothly at its operating position (impeller end down), nor horizontally, but did ran smoothly "upside down". My guess is the bearings or bushing that bears the weight of the spinning parts of the motor itself are worn out. Suggestion to Porsche... make your fuel pump motors run in a horzontal position. But then no automobile is suppose to run forever... without maintenance. Since this incident was my first dealing with a Porsche dealership and seeing all the cars going in to the service bays, I pretty sure the dealship makes more money from servicing than selling Porsches... yep, I am new Porsche owner.

Edited May 24, 2013 by Ricky1