I have a 955 Cayenne Turbo. It started surging and then the engine would die yesterday. I ran my Durametric and had an air pressure code and cleared it. (I found my gas cap loose and tightened it, then it ran fine. My pig drove fine the rest of the day, and I drove 50 miles to work with no issues this morning.
I started it to come home.
Starts with no problem, but a few seconds later the idle drops, I have no power and it dies. I start again and it drives like 20 feet as normal, then dies again.
No change with fuse 13, and then fuse 14 pulled.
No change with my (new MAF sensor) connectors pulled
Oil cap pulled...it dies real fast.
I didn't notice any vac leak sounds, but engine is just barely able to run for about 2-3 min in park, then dies.

All new as of today:
Starts fine and a few seconds later starts stumbling and will not accelerate at all. PSM failure light comes on and the triangle with the circle light is on. Then the auto level notification says it is off and it won't turn on.
The grey sensor in the front of the throttle body is constantly making a running sound, like super fast clicking, until I unplug it.. even with engine off, it is clicking. I'm hoping this is the problem. I'm not sure what that is right now, but I think it runs down to the diverter valves. Perssure regulator? Anyway, I also got a key not identified warning when I went to lock her up tonight.
Codes everywhere. Barometric pressure exceeded value, X-Boost exceed limit????? Never seen that. PSM failure...on and on, but the rest are fairly common codes I have seen that are for little things like tow electric signal is high. No check engine light. Also no check engine light when it is barely able to idle.

Any informed ideas? I hate my local Porsche shop. They suck.

Not sure where to go from here. probably cry all night first. lol

 

Forgot to mention I get a DME? failure code too. Could it be the computer?

 

Hmmm. How old is the battery? When they are failing all electronic hell can break out.

 

E-throttle calibrated, but never reached "14" as durametric says. it is at 11

 

battery is 3 wks old Bosch AGM. Listed as a Porsche replacement and has power to keep starting the pig over and over

 

OK. Is my boost control valve suppose to be clicking very rapidly with the engine off? Could that be causing my car to run so poorly? I did have a boost code that I have never seen. has anyone had an issue with this part, and any symptoms?

 

N75 valves are known to fail.

I would check the voltage @ the battery while the car is running and @ cranking.

Maybe disconnect the battery and and adapt the throttle body after you reconnect it before you start.

Sometimes with vehicles as electrical dependant as the cayenne, you can set a lot of codes in the window of time that the engine is running below idle speed and when it stops. While it's struggling to stay running the voltage can drop because the alternator is not charging. These Cayennes cannot run on battery alone even for a short while. Not like the old days.

 

Should still run with the oil cap off, however you will notice rougher running and a change in idle. I'd bet you have an emissions leak.

 

OK... My electrical sys was malfunctioning because I only had 500RPM's and everything went crazy when I plugged in my Durametric. I found a loose connection at the primary fuel pump relay and fixed it. My primary pump is all clogged up and the filter is very nasty. I pulled no. 14 fuse and now my car can run and drive running on the secondary pump only. Now that my car can run, I plugged in the Durametric and checked everything. I cleared my codes and it is running great on one fuel pump now and all, well, most of my electrical syst. is now acting fine. Crazy how one little thing can reek havoc on everything with these cars. I just ordered everything to replace both fuel pumps, relay, FPR, Filter, seals, and I'll be getting this all in this wk end if all goes well. Pelican parts total $750.00. My Local Porsche shop wants over $1200 for the same parts. My N75 valve is making strange sounds, but boost is perfect. Maybe I just never noticed the valve making noises before. haha. I'll update after everything is replaced.

 

Oh. Forgot to mention. My E-throttle calibration will still only say 11 on the bottom number after calibration. Does it have to be 14, per Durametric? How do I manually change this setting? I don't want to be guessing. Thanks for any input.

 

Put in new fuel pumps, filter, and pressure regulator. She is running and idling great now with fuse 14 back in. But, It's a Cayenne, so when I connected my battery again, I have one wheel that will not level the suspension....sigh. To tired to mess with that today. Back to fixing my suspension again this wk end. Happy she is running really well though and the other electronic issues just stopped on their own. This car is possessed. Fast as hell for a SUV, but gremlins love living in these cars. haha

 

make sure your oil cap is tight and the seal is cool, if not it will feel like your engine is coming apart.

 

LOL read above before posting randomly.

Anyway. The car is running great, but just a quick note. Be sure to zip tie your fuel lines up as much as possible if you tackle this project. Pelican Parts has a great write-up, but they didn't mention to be careful to keep the fuel lines up. Now my gas gauge is stuck. I think I blocked the bobber. Just focused on getting all the lines in the right position, but looks like I have to go back in to free up my bobber/float.

 

Yep. The bobber was hitting a fuel line. It is on the driver's side. Fixed....well now my faulty suspension workshop problem has returned because I had to disconnect the battery. Durametric can't read data, so I'm stuck with the pig leaning to the left now and jacked up in the back. ahhhh