F6C

Thanks. I'm just getting misfire codes across all cylinders and the overall misfire code, that's it, no other codes. Have replaced the MAF and then the cam actuators on both banks to no avail. Superficially it runs / feels fine most of the time and doesn't throw a CEL, but it's always logging some misfires in the background if you watch the live data and sometimes enough to trigger a solid CEL. Just occasionally, it triggers a flashing CEL and runs rough. Restarting the car has it running superficially OK again. Frustrating!

F6C

Just to clarify one thing - the fuel pressure codes will be in the DME, right? Not some other subsystem?

BLU997

Hi Hindsight,
sorry about the delay for this...

Fuel line removal: Loosen both fuel lines and unscrew the fitting nuts as far as possible. The fuel lines are flexible and can be fully removed once the HPFP pump has been unbolted and slipped out of its mounting location.

Fuel line refitting: Be sure to re attach both fuel lines to the pump (finger torque only) before slipping the HPFP back into its mounting location. Do not forget the special fitting lube or final tensioning of the fuel line fittings.

Coolant Hoses: Piinch off the smaller coolant hose that goes back to the tank, use a commercially available hose crimp tool from an auto store to prevent damage to the coolant hose.


Cheers,
Craig

abolsh997

Dear Hindsight2010,

thank you very much for the detailed information.

ebirck

Hi all,

I have a 987.2 Boxster S with symptoms of a failing HPFP, I bought a Foxwell NT530 to diagnose and see most of the same errors (e.g. fuel high pressure improbable), but I’m having difficulty figuring out where to see the HPFP set pressure. Trying to corroborate my data against what @BLU997 posted, Under OBD > Live Data I see “Fuel Rail Pressure” but no set pressure, and the rail pressure hovers around 550kPa which sounds more like the low pressure fuel pump pressure…

Are those sensors a 997 specific thing, or is there another update I need to download maybe?

fouckhest

Currently working through some similar issues on my 987.2 CS, are you getting any codes? My car continues to intermittently throw P0004 (Upper limit value exceeded), which oddly seems to only come during very lax/cruising diving, not spirited driving.

ebirck

@fouckhest Yup, most notably codes P1023 and P1026 which are "Fuel high pressure too low during starting" and "Fuel high pressure implausible", respectively. You can see my whole thread on it here

I never saw P0004. Not entirely sure what that corresponds to (I'm just figuring this all out myself), but the high pressure rail does seem to build pressure at idle / low-load for me. Probably because it can't keep up with the normal requirements, so only when it's not under load can it build to a reasonable pressure.

Are you self-diagnosing or did you get input from a dealer / shop? I'm pretty comfortable tinkering but lowering the engine has me doubting doing this myself; wondering how much to expect from a more experienced place.

fouckhest

Thanks for the reply @ebirck I will take a look at your thread.

P0004 is a signal too high code at the pump, there is unfortunately very little information on this code for the 987 cars. I've found where there was a service bulletin early on for pumps, but no solid info remaining at this time.

I am not self-diagnosing, when the code first appeared I took it to my local indy shop, they did all kinds of tests measuring values of the pump and said they couldn't find anything wrong. It has me leaning towards a wiring issue; the code appeared during light driving last weekend, so I put the car on the lift, removed the connector, sprayed it with cleaner and put some dielectric grease in there. Will hopefully get it out and drive it again soon and see if it come back.

BLU997

These are the two addresses to compare fuel pressure setpoint vs actual. You can make the 530 output a graph in real time.

ebirck

Thanks for the screenshot, is that under the "Live Data" section for you? I don't seem to have those on mine. Maybe I need to update the firmware? I already have the Porsche plugin (logo on the home page and lots of module-related tests)...

BLU997

Hi,
I'm away overseas ATM, so I can't put my hand on my NT530. I found the fuel pump functions by literally stumbling around in the menu tree on the foxwell.

I think I actually wrote small notes to help me remember which path i followed, then navigated out of then into the next section on a journey of discovery.

Researching this answer for you I also found an HTML excel that contains 4896 lines of Porsche menus for the NT530. 450 lines for 997

My best guess is DME/Live data.

Good luck!

Fast4fun

2009 3.6l 997.2. 72k miles. Starting has been getting longer especially after sitting for a few days. Now, when I turn it over after a few days, the idle stumbles and fails. Upon the second or third attempt, I’ll juice the gas pedal and it goes to idling just fine. It may stumble once as I begin driving but once underway it runs fine. It will restart the same day without issue. I ask if this is likely due to HPFP because I’ve been to the dealer twice with no resolution. I’ve had one ignition replaced and one battery replaced without any improvement. Since there are no codes thrown or check engine light, they don’t know what to do. Thoughts?

Fast4fun

Video Link of second attempt to start

Fast4fun

I found this which captures my symptoms perfectly.

https://www.planet-9.com/threads/981...essure.251372/

BLU997

If there is a large gap between the HP fuel set point and the HP fuel actual, there is a HPFP failing.
I bought a new HPFP online and changed it out at home, technical, but do-able for the enthusiast.
Fixed all my fuelling problems right away.
Good luck!



Get your tech guy to compare your high pressure set point vs your actual high pressure value.