Need Help- Rough Idle Engine Dies

[mharris65]

Let my son take the Cayenne to prom while I was out of town. Of course, it chose that moment to have a major issue. Engine started running very rough. Died several times. We had the car towed home. Now it starts up fine, but idles very rough and will die after a minute. If you try to rev the engine in neutral it will make about 3K RPM before sputtering a bit and quitting.

I could really use some idea of what this is before I take it to my mechanic. Strangely, It was just in the shop two days before this incident having the rear drive shaft replaced. Could any of this be related? The car threw two codes which are gone now P2177 and P2179. Both related to "lean of peak at idle". There are no other warning lights or codes displayed.

Thanks for any help the members can provide.

04 Cayenne Turbo

Edited May 11, 2012 by mharris65

[wvicary]

Test the fuel pump pressure and volume. The Cayenne uses two fuel pumps with the main pump and filter unit being located under the left side rear seat, the secondary assist pump located on the right side.

[mharris65]

Thanks to a little more research on this forum and the great tip of removing the fuel pump fuses one at a time, I was able to isolate the problem to the primary fuel pump. It's running fine now on the secondary pump. Does anyone know if it is okay to run on this pump for a while? I'm not going to be able to get to the fuel pump replacement for at least a week.

Wvicary, thanks for you comments. I assume right and left refer to exactly that as you view the pumps from the rear of the car. In the diagram online it sort of seems like the pump are fore and aft under the seat. Can you just confirm that the primary is the left pump (Driver's side) under the rear seat?

Thanks for the help and thank goodness for this forum.

[wvicary]

View is always referenced from the driver seat ( left hand drive ) facing forward. The primary pump is the left pump and recommend changing the fuel filter module with pump replacement. Sorry I've no idea about operating solely on the right pump but would get the defective unit replaced asap.

[hahnmgh63]

If your gonna drive it for a while keep your fuel tank over 1/4 of a tank if running on just one but when your ready to change it stay close to home and run it down a little as less fuel will make it easier.

[UTRacerX9]

How many miles are on the car? Just curious as to how long it lasted before failing.

[mharris65]

The truck just passed 90,000 miles. Seems like the drive shaft and the fuel pump picked the same week to expire.

[hahnmgh63]

Seems like there have been a lot of Fuel pump failures in the last few months. I just put my '06 on the lift last night to check the driveshaft (no reason, just taking a look) but I'm afraid if I look at it then it will fail, and that with all of these Fuel Pump failures that I'm jinxed :)

P.S. Hennessy just sent me the new '09 coil packs so I'm sure my old '05 ones won't fail anytime soon.

Edited May 12, 2012 by hahnmgh63

[ekstroemtj]

I had exactly the same issue after I replaced my coils and plugs. Believe it or not, after disconnecting the battery for some time the car run fine again. I would give it a try.

[mjohn45]

My 2006 Cayenne (V6) keeps dying at idle especially when stopping at a light.  I seem to be able to avoid it by keeping the accelerator slightly pushed in while holding the brake with the other foot.  The car has drive by wire so it seems to limit the revs until I release the brake. I replaced the ignition coils about 6 months ago and I did have a very rough idle and one broken coil.  I have looked through these fuel pump notations and I was thinking of checking the pressure on the lines.  I noticed that there are fuses to pull for the primary and secondary pump, is there anyone here that knows the system well enough to suggest next steps?