Finally! I got a CEL for my 2012 Cayenne Base (3.6L V6).

I have experienced extended cranking when I started the engine (Especially when the engine is cool)

P0089 popped up on the dash but I dis reset the code twice.

I thought that it would be battery problem since it's over 5 year so I recently replaced it with a H8 AGM battery.
However, Cayenne still experiences the same symptom.

I didn't see CEL today but I checked the fuel pressures to figure out what's going on. As shown in the photo, the scanning (OBDII & iCarsoft POR II) results show the error code (P0089) with a brief description.

What I have observed is summarized below:

1. "Fuel Low Pressure Actual Value" drops rapidly when the engine is shut off. (it's dropped from 83psi to 35psi within 1 min.)

2. "Fuel Low Pressure Actual Value" maintains the similar value to "Fuel Low Pressure Setpoint" during the engine's running.

3. When I put the key in ON position (Not started yet), "Fuel Low Pressure Actual Value" was quickly up to the set point. (It seems that the fuel pump works well.)

4. Fuel High Pressure Setpoint and Acutal Value: There is huge gap (3.5MPa vs. 0MPa) but I am not sure if this is normal or not.

Based on researches, P0089 would be related to:

1. Fuel Pressure Regulator (FPR)
2. Fuel Filter
3. Fuel Pump
4. High Pressure Fuel Pump
5. Fuel Line(s)
6. Something else

From 958 Cayenne, there is only ONE Fuel Pump under the right rear seat (beneath the fuel regulator).

Since I don't experience any misfire, lean and/or rich conditions yet, I plan to start repair(s) - replacement of a FRG & a fuel filter first.

I still want to check this with the Cayenne experts here in this forum. Any expertise or recommendation would be extremely helpful! I am sure that this would be beneficial to other folks here.

Thank you!

Attached Pic 1: Summary of the problems with fuel pressures
Attached Pic 2: Fuel Components for 958 Cayenne (no more two fuel pumps)

 

Over the weekend, I tested the Cayenne a little further.

I monitored fuel pressures "during driving".

1. The fuel pressures were dropped from 72.5psi to 38-50psi (fluctuating) AFTER the engine warmed up (about 7 minutes later).

2. Although CEL was not on the dash yet, P0089 code can be read through the scanner. This CEL code was triggered as soon as the fuel pressures dropped (38psi ~ 50psi) during driving.

3. I drove more than 40 minutes next day and the CEL warning sign was finally shown on the dash.

4. I deleted the code by using the scanner again. No bad symptom yet.

I am not sure if a bad fuel pressure regulator and/or a clogged fuel filter can cause this type of symptoms.

Any expertise?

 

Isn't the '12 V6 direct injection? If so - there is another fuel pump. Mechanical one, probably running off the back end of one of the camshafts.

 

As far as I know, there is a high-pressure fuel pump next to the engine. Based on the CEL code P0089, I am trying to check the low-pressure fuel components first. I hope that I am on the right track. Thanks Deilienberger!

 

I found the culprit!

The following is the procedure to solve the problem.

1. Replaced fuel filter and fuel pressure regulator --> Same problem returned

2. Replaced the fuel pump --> Solved the problem!

I used a VDO fuel pump which is Porsche OEM fuel pump, i.e., identical to Porsche fuel pump but almost $200 cheaper.

Summary of the issues associated with the bad fuel pump.

1. Fuel pressure drops only when engine is hot --> Signs of bad fuel pump
2. When the key is turned off, fuel pressure starts dropping rapidly. This means that a check valve in the fuel pump has a problem because it doesn't hold the pressure.
3. P0089 was gone after the fuel pump was replaced.

It's not easy to do replace fuel components so replace fuel pump, fuel regulator and fuel filter at the same time if they are over 4-5 years old.

My Cayenne runs well again and no more extended cranking to start.

Hopefully this helps for others!