GlenC

2008 Cayenne S starts and runs fine. Fuel high pressure setpoint and actual values match. After driving 20 miles, shutdown and leave car for a while and when I return, car starts normal, idles for 5-10 seconds then gets rough and ultimately dies. HP fuel pressure drops from setpoint like being starved of fuel. Fuel pressure, key on engine off, about 5bar. Now history: 135K miles Cracked fuel filter - Replaced Engine would die at 1/2 tank.... bad LP fuel pump - Replaced Both VDO (138K) Then in a few hundred miles the problem mentioned above started happening every few hundred miles Replaced fuel pressure regulator - problem happened again Replaced High Pressure Fuel pump and Sensor Problem still exists ....

Interesting read.. I am having a problem with my 2008 Cayenne S Had a fuel filter crack and leak, so replaced that. About 3000mi later started having fuel pump problems (at 1/2 tank it would shutdown while driving) Ultimately when it shut down, I could pull a pump fuse and it would run on one, not the other. With 137K miles, I replaced both pumps. Everything seemed fine. A few hundred miles later, I drove the car 20 miles to a friends house. A couple hours later, we went to leave, started normally, but in about 5-10 seconds, started running very rough and shut down. 3-4 restarts the same. About 4-5 hours later, I went to leave, thinking I'll need to call AAA, however it started and ran normally. It was normal for the next few months and few hundred miles. Now about 200 miles later, the problem has become very frequent. I did manage to get it to run, started driving home, however noticed it would falter if I tried to accelerate ...... drove 20 mi home no issues driving easy. Today, checked Durametric and code 1025 was there. Started and ran, HP setpoint = 40, HP actual was about 36-44. Graph of actual value was like a wavy saw blade.... 1 mb fluctuations in the values as values went above and below the setpoint. Cleared code 1025 and it returned. The Fuel high-pressure adaptation values 1-5 range from 0.9 to 1.25 Fuel high-pressure adaptation range 1 = 1.0 Went back out to drive car with Durametric running. Cleared the 1025 and CEL went out. The fuel HP values seem to closely follow the setpoint. This time there was no faltering while accelerating, everything seems normal. The difficult part is this may act normal for >100 miles or <20 miles, I won't know until it happens. Anyone with the Durametric, How smooth is your actual HP Fuel value and how much fluctuation compared to Setpoint? Unfortunately, I have a family trip planned, towing the Airstream, in 8 days.... I need to find the problem. At this point, I'm leaning towards replacing the HPFP....

I'm looking for the wiring diagram for the Cayenne Turbo seats. Since my back does well in my '14 Cayman S and '08 Cayenne S seats, I purchased a pair of used '16 Cayenne Turbo seats to put in my '75 GMC Motorhome I am restoring and would like the wiring diagram to utilize seat functions other than just power and ground..... I will not be connecting the air bags. Thanks

Just had to replace mine, '08 CayenneS. It developed a crack and started to leak after 134K

It's been so long ago, I forgot I even did this.... As I recall, I had to take off passenger side air flow sensor and the intake pipe, the loosen the belt then a very tight space to get at the sensor. Sorry I don't remember more.

Thank you for the idea, it got me out of a bind and was $0 ...... Car was in at my local dealer last week and they saw the fix.... they were surprised when they saw it, but agreed it was better than spending $2k or so for the shaft replacement.... I have over 8K on the fix and sort of forgot about it....

My 08S with 108k gave me the sudden banging Wednesday during acceleration... thought I ran over something, til it happened again.... Searching the internet.... driveshaft support! Put it into Special Terrain Mode and crawled under to check, yep, shaft loose.... Normal driving and there is no sign of anything being wrong, drove 50 miles home on Fwy before starting repairs.... I'm starting to think my trips to Yosemite are cursed!!! Last year, 1st trip, a coil pack failed (second one) about a half hour out of Fresno on a Saturday morning..... found a replacement and was back on road later that afternoon... (after I got home, replaced remaining 6 coils). A couple month later, back to Yosemite.... leaving the park the first night, the melting snow and darkness hid a big pot-hole.... sudden blowout! (ultimately new control arms and 2 new tires).... The next day, cones in place.... 5 cars had blowouts while I was changing my tire that night! Planned a trip to Yosemite next week and Drive Shaft Support failure.... Fortunately I replaced the Thermostat, Water Pump and repaired the loose tubes in thermostat housing last month. Since I'm limited on time, I decided to go with the hose repair method. Can't really see any reason this won't last for a long time. This shows the rubber support failure: This is where I cut off the rubber support from bearing and housing, leaving the rubber that was attached to the bearing and housing. I had some 3/8" air hose that was just about the right size. I cut pieces 1" (25mm) long and tied together with SS Safety Wire. I think I actually used a total of 13. I tied them around the bearing first, then slipped the housing on at the top first, then used a screwdriver to compress each piece of hose at the bottom to fit into the housing. Once I got the housing in place, I used safety wire to hold the hoses into the housing. I figured the safety wire was a longer lasting product than cable ties. The fix works, no noise, no vibration on hard acceleration.....

I just discovered that my failure in the thermostat might not be the thermostat but the wiper seal that's inside the thermostat housing. Information on some of the other forums got me to looking inside the thermostat housing and after a trip to the dealer looking at a new housing there is in fact a seal or wiper pressed into the thermostat housing that seals against the sleeve on the thermostat. The lip of the seal is totally gone on my housing and if I put in a new thermostat I would come up with the same problem again. Now it's time to find a replacement seal I'm going to try and find a PTFE wiper seal Sent from my SM-G920V using Tapatalk

Next step is to replace the O-rings on the coolant pipe in the rear of the Thermostat housing

Finished installing pipes in thermostat housing.... One pipe installed and epoxy spread on inside of housing for second pipe... I used the radiator hoses to hold the pipes in the proper position while the epoxy cures. Spread epoxy on pipe before installation... Both pipes installed I'm quite happy with the results..... and saved $300++ Glen

Yesterday I got the pipes & housing cleaned and ready to install pipes....

Guess I'm going to epoxy the pipes back in, both were loose..... Glen Sent from my SM-G920V using Tapatalk

Great help! Thanks! Got into my '08S and found the pipe loose on the thermostat housing.... guess I'll try cleaning and using epoxy to reinstall.... the epoxy I use for golf clubs seems to work fairly well.... Sent from my SM-G920V using Tapatalk