[987kmns]

Glad to hear the new HPFP cured the problem!

[thedude2u]

Hello all. I`ve been monitoring this thread for some time as I have recently had the HPFP replaced on my 2008 CTT. I had the same symptoms. Rough idle, hesitation/jerky acceleration, and eventually stalling (scary when driving!). There was no noticeable smoke with any of these conditions, but I`m sure it could be possible given the rough running conditions.

Normally this is a job that I would take on myself. The OP did a good job writing up the swap and it looks easily within reach of the average shadetree mechanic. However, my wife and I were moving across country and my tools were in storage over 2000 miles away. So I swallowed my pride and took the car to the dealer to have the pump replace at ~$2k.

The pump replacement seems to have fixed all of the issues. I haven`t experienced any crank/idle/stalling issues since. However, I have a new problem now that I think may be related to the pump install. The engine/transmission now seems to be surging a low/part throttle and the upshifts have become very harsh. When I am cruising around town (low engine load) and going on/off throttle, the engine seem to apply to much power and then too little causing the acceleration to oscillate. It honestly makes you kind of queasy after awhile.

Is there a calibration procedure or software update that is supposed to be done as part of the HPFP replacement? I don`t have any active codes currently (at least visible by OBD). I don`t have Durametric currently (thinking about buying a kit) so I can`t monitor the current rail pressure to see if it is out of spec. It just seems coincidental that these symptoms started happening right after the pump replacement. It`s driving my wife and I crazy!

Any ideas? Anyone else with similar symptoms?


P.S. I know I`m not living in VA currently, but I thought I would post since this is one of the better HPFP threads I found online. I`m originally from Roanoke and graduated from VT. That counts, right?!?!

[boxs]

MY CAYENNE STOP ON THE HIGHWAY
I plug it to diagnostic tools and i have this message (camshaft pos. sensor bank 2 range )
I had change the camshaft sensor on both side and the engine still not running
Rough Sound smells Gas .
Do the engine skip a tooth ?
Helpp !!!

[Dr K]

We've gone international. Unfortunately, Boxs, I can't help you. Good luck, though.

[Parenn911]

Great thread, excellent write up!

[missing951]

Hi I am experiencing somewhat of a different problem. I have 2008 Cayenne V6 which also has a HPFP for its direct injection system. I keep getting a CEL (check engine light) that comes and goes. No drivability issues, no power loss although it runs a bit ragged at startup.

The code that comes up consistently with my Durametric is P0674:

P0674:
Fuel rail pressure sensor - inappropriately high - Upper limit value exceeded, test conditions are not-completed, fault is currently active and is not causing a DTC light.

Sometimes also accompanied by

P1057:
Warm up catalyst efficiency below threshold bank 1 - Value below lower limit value, test conditions are not-completed, fault is not currently active and is not causing a DTC light

I have replaced the Fuel rail pressure sensor, but unfortunately I don't have an appropriate fuel pressure gauge to measure the actual values. The V6 ECU does not report the fuel pressure like it does on the V8s for some reason so I can use the Durametric to get the actual values.

Could a failing HPFP cause a too high pressure condition? I was thinking the nonsensical too high reading had to be an electrical fault of some sort thus the replacement of the sensor. I have not dug into the wiring harness or anything like that yet because it will be a nightmare to get to. A previous post mentioned that it is the check valve in the pump that tends to go(preventing it from building pressure) rather than the mechanical pump itself. Is there a built in relief valve as well?

I've been stumped by this for some time but since there was no change in drivability (just the CEL) I have let it linger. Any thoughts?

[nasocbr]

Hi all,

I have the same problems with my HPFP and I am planning to replace it soon.
How can I get the photos from the DIY instructions on the first page?
I am a bit concerned about this "clutch" and mounting.
Is there a calibration procedure or software update that is supposed to be done as part of the HPFP replacement? i don't have Durametric or any other software.

Thank you

[tmiller02]

ditto.... any idea where the pictures are?

[Jazzbass]

Photobucket used to be a free image host but about a year ago they turned off free hosting and broke millions of bbs posts like this around the world. Hopefully the original poster will edit his post with images uploaded here directly.

[987kmns]

Pump drive:



Pump drive with clutch and stopper for illustration purposes only. The clutch and stopper are attached to the camshaft first as shown below.



The following photo shows what the camshaft looks like with the clutch removed (I'm using a mirror to see).



Now, with the clutch and stopper installed.



Finally, it is time to reinstall the pump. The low pressure fuel hose gets connected first. Then, the electrical connector as the pump is lowered into place. I found that it helps to roughly orient the pump drive the same way as the notches in the pump clutch. Jiggle the pump into position. Install all the bolts and shield and you are done. Here is the finished product.



Old pump PN:



New pump PN:



I hope this helps. I wouldn't say that any of this work is very complicated, but it does require patience as the space between the pump and firewall is very small and you have to work by feel most of the time. The job took about an hour and half to complete the first time and 55 minutes the second time.