OP - anything remanufactured on this vehicle is likely from China. The Cayenne is one PICKY vehicle: you simply cannot scrimp on anything. Break out the Credit Card and buy the OEM dealership HPFP. I experienced the same exact issues on my old 2009 GTS 6MT.

 

damn.. i had a very expensive year....
electrolysis damage to the running gear and through hulls on my bertram... $12K
trans in my ram 3500 crapped the bucket with only 50K miles.
blew the engine in my caymans at VIR last month...

tried to cheap out on the pump, figuring it would work but maybe not last as long.

 

Curious if you fixed your issue and if so, what was the solution?

I'm having a similar experience with my '08 S. At first I was certain is was the HPFP. I was getting long crank, no power / engine surging at RPMs above 3000, and the P1026 code. Having read the horror stories of the cheap e-bay parts, I decided from the get-go to buy a Porsche part from a reputable source online. It took me a couple of weeks to find one that was reasonably priced and readily available. The only ones I could find were remanufactured pumps, even from the dealerships.

It took me a few weeks to get the time to install the rebuilt pump, but after install, I was still getting the same symptoms as if the HPFP made no difference. I assumed that the HPFP was a good part so now I've also replaced both of my in-tank fuel pumps, the fuel pressure regulator, and the fuel filter...I figured the car has 110k on the originals so worth doing, even if it wasn't causing my issue.

Well, still no improvement so I took it last week to a local indy to have them check it out. They verified the in-tank pump system is working as expected but the HPFP isn't putting out any additional pressure. They too were assuming the pump was good since it was just replaced so they proposed they remove it and inspect the camshaft lobes for wear for a mere $665 (labor only). Uh...no thanks...let me know if anyone thinks that could be the issue but no one else that has posted about their HPFP ever mentioned a worn camshaft being the root cause.

At this point, I'm wondering if I simply got a bad HPFP, even though I bought a Porsche rebuilt part. The downside is the reputable supplier I purchased from is currently showing a late March ship date so I'm hoping there's another something I can or need to try before exchanging it.

 

What is considered a long crank?

I do not have a solution but some input that will not help, but some cause for thought. I ask about crank time because my 08 S was taking maybe 3-4 seconds at times to crank. I had the "low pressure during start" code on the Durametric. It has been going on for a couple months. I would open the door and the pump would run. After closing the door and leaving for an hour I would open again and the pump would run again. If really cold out the crank for be a bit longer and after start would run rough for a few seconds, then smooth out. After that it seems to run well.

I was/am putting off doing the pump hopeing for a cheaper fix. A couple days ago I replaced the coil packs and new plugs since I have no good service history. The code for the pump went away and I seem to have a shorter crank, perhaps only a couple of seconds.

I know you said you posted that you changed the coil packs and plugs but just wanted to throw my experience out there. Will check to see if the low pressure code comes back but following this to see what else might cause that long crank.

 

My long crank is about 5 or more seconds, sometimes longer.

FWIW, I first got the P1026 code several months ago but, other than the long crank first thing in the morning, the truck ran fine and cranked fine the rest of the day. I cleared the code and it didn't return until a few months later. The code might have been pending but I never checked until the MIL came on again, but at that point, the truck was running very roughly with low power, etc.

If the coil packs were failing, I would assume you'd get misfires and likely on a consistent cylinder (e.g., a P301, 302, etc codes vs just P300 for multiple cylinders). Perhaps that's a poor assumption.

 

Thanks for the reply. I do not think mine has been quite that long. I also have never gotten a CEL. I decided to change them all since I did not have any history and t has 105,000 on it. Was taken good care of it seems, but I did have a misfire on #5 code when I went to reset the service interval after I did an oil change. Never came back (yet) though, so I figured they had to be fairly old.

Hope you can get it sorted, can be maddening, and expensive, to keep trying without success.

 

Closing this out, hopefully permanently, for those that may come along later with the same issue. I returned the HPFP I bought in exchange for a new one and with the fresh replacement installed, the truck runs like a dream. Starts better now than when I bought it so I had no idea how it was supposed to start up. It's almost like an instant on button when you crank it. I highly suggest anyone with a similar issue after replacing their HPFP, don't rule out too quickly that your HPFP may be a bad part that wasn't properly rebuilt (even if purchased from a reputable supplier and it's a Porsche rebuilt part).

Next on my list is fixing the squealing A/C blower...

 

Same here, I ordered one from Amazon because it is quick. Later I found it is weak and replace with OEM one. I also changed the censor.