mdk100

I posted this on another forum, but have found several discussions over here about the HPFP. It appears this was an issue on the 2009 997's, but I'm wondering if it has been an issue on later years. I went from a 997.1 Carerra to a 2012 GTS (having not enjoyed driving the 991). However, there are some things that dissatisfy me about the GTS, which I've primarily attributed to lack of low end torque.

The 997.1 base Carerra would really pull away from a stop, but I've stalled the GTS several times, particularly on "normal", not "sport" mode. I've driven manuals for decades, even in the hills of San Francisco, and have never killed a car like this GTS, so I don't think it's my clutching.

The car can be slow to start in the morning and has a very erratic idle on first start for a minute or two. There also seems to be a power dip right below 3K rpm, then it howls.

I found this thread discussing the HPFP, which actually sounds similar to what I've noticed:https://rennlist.com/forums/porsche-...re-08-gts.html

From 997for40:
"HPFP symptoms @ least in my case.

3-5 sec. delay in firing up
engine vibrates when it actually starts
erratic rpm reading then settles down to normal
won't take full throttle when it hits 2700-3K rpm (bogging down)
overall runs like crap "

Anyone have any experiences with later year 997 HPFP issues? I hate the thought that this is "just the DFI engines". Other observations?

jeffrec

I own a 2009 C2S and have reported similar issues with the car appearing to hesitate slightly between 2700 and 3000 RPM, and fortunately for me I have not experienced any of the other issues you refer to. My car starts on queue, idles a bit high for about 30 seconds when cold, and then settles down to about 800 RPM at idle. One thing I have discovered with my clutch is that I have to give it a bit more gas than I would think to start on a hill. BTW, if you are a member of PCA you can do a search on technical Q&A regarding the hesitation at 2700 RPM and the answer I received was that this is normal for this engine. Overall I love my car and really don't have any complaints. And one more data point, assuming that you follow Consumer Reports, the 2009 model year was rated much better than average (excellent).

Wayne Smith

Does this matter?

When I was looking for my car I debated with myself ad nauseum about whether I wanted MT or PDK. I still do. PDK won the deciding battle, but I don't think that matters. Either I am in traffic/commuting in which case I am under 2500 rpm, or I am having fun. Fun mode from a stop allows first to take me to 5K and I never see below 4K again. There is so much dv/dt in first that I have never noticed a 2700 to 3K lag.

My Supra Twin Turbo had a major short coming below 1900 rpm as the first turbo spooled up, and a hole from 3800 to 4K as the first dropped out and the second spooled. Maybe I've just trained myself to ignore and work around the valley. The Supra required some effort to do this. Assuming the 911 valley is there, it seems pretty harmless to me, unless it shouldn't be there ...

BTW: As a newcomer, I continue to be amazed and impressed at how aware many of you are to the nuances of these cars. It's incredible what you see in the posted pictures (do I need a bigger screen?) and what you realize as you drive (have I gone numb?). I do enjoy your observations and your sharing of knowledge. Thanks.

CosmosC4S

I think you got a Lemon......

beden1

I bought my 2012 GTS cab with MT after selling my 2009 Corvette Z06. I've had cars with manual transmissions for over 45 years. I did stall the car a couple of times when I first started driving it but have not since. I have found that I need to give it a bit more gas at start-up/take-off from stop as compared to my Z06, but since the throttle response is so excellent, it did not pose a problem for long. I think you need to practice and get in tune with your car's feedback.

I have not had a problem with the HPFP, but did have the main CPU replaced, as the car would stall out from being starved for fuel at speed and would have a hard time starting again. It took the dealer and Porsche three plus weeks to figure it out but it's been fine since. This happened when the car had around 1,500 miles on the odometer.

I did not have the issues you list, and from following a BMW forum, it sounds like your car may in fact be having a HPFP problem.

Schpee007

The HPFP on my 2009 C2S was replaced under warranty. I did not own the car when the replacement was done. I can say the car exhibits none of these symptoms now.

beden1

i checked with a friend of mine who owns a 2010 BMW and had a nummber of fuel pump issues. He felt your symptoms sound more like what he had in his car when the LPFP (low pressure fuel pump) needed to be replaced.

When his HPFP was having problems, the car went into protection mode with diminished power so he could at least drive it to the dealer.

powderzone

I can't comment on the HPFP but regarding accelerating off the line...there is a lot of downforce on those rear tires in a porsche relative to wheel hp so I find that giving a little shot of throttle before releasing the clutch helps.
And dumping the clutch is a sure fire way to boost your maintenance budget and stall.

beden1

Yes, that's what I do now that I think about it. A little blip of the gas pedal does the trick.

stefang

Well, I have an '09, which had the HPFP replaced in '11 and it just failed again. I had many of the same symptoms and obviously the later pumps were still susceptible. I was told the one I just put in was redesigned. Since your's is under warranty, I'd go to a dealer and have it checked. Mine had secondary codes pointing to HPFP when I brought it in, but no CEL.

Petza914

I don't know about the 997.2 cars but in the 997.1 cars there's a switch built into the clutch pedal assembly that changes the way the engine runs as the clutch is being released to prevent people from stalling their cars and to reduce clutch wear for those that don't know how to properly drive an MT car. In my car it would cause this stumble as I pulled away from a stop. Bypassing the switch by connecting the two wires that feed it resolved the issue for me and the clutch and engine now feel and react much more directly, like a cable actuated clutch. Others have done this same mod - some with good results and others with not so good (warning lights, etc) but I don't have any of those issues. I simply drilled out the dead end portion of a wire tap scotch-lock, put both wires in it, crimped it with the pliers, closed the lid, and I was done. I'ts completely reversible by removing the tap and recoating the tapped wires with liquid electrical tape.

A search here and I think on Planet-9 (it was originally discovered by a Boxster or Cayman owner) should turn up the info you'd need to pursue this. You might give it a shot and see if if makes the car behave more they way you want it to when starting out.

wheeler

That's an interesting take. There is a switch on the .2 car as well, as it knows if you don't have it pushed in when trying to start the car. Perhaps part of the hill holding clutch mechanics? I have noticed a few times I've had the clutch pushed in and it won't start and I have to pump the clutch once again to trigger it. I do think "normal" driving mode (for those with the sport button) is dumbed down quite a bit for people that are either new to a manual or haven't driven one in a while. As sport mode is extremely touchy and it's easy to "buck" the car if you give it TOO much gas in sport mode when leaving a light. To me "normal" mode is probably dumbed down TOO much. The throttle response is hilarious. Just go out to your .2 car, let it idle and tap the throttle quickly. Tap...rev....tap....rev. For a car that has INSTANT throttle response once you're moving, the delay from a dead stop is comical. To me this is what screws up the take off from the light more than anything. We all know how to drive a manual, it's a feel and muscle memory thing. This throttle response is so off, that it screws up your natural throttle blip and clutch release that I use on every car, truck or bike I drive. So yes, that extra throttle blip before you leave a light helps, but if you're not paying attention and try to quickly put it in gear and take off with traffic, it will try to stall every time. I've learned that even if I'm getting honked at for not paying attention to the light, I HAVE to take my time leaving...that or romp on it! :-))

I responded the OP's thread on 6speed. The problem is real, it has nothing to do with "working your clutch technique" or getting a lemon. I can hop in my buddys 996 GT3, 07 Cayman, 11 boxter spyder and pull away like I'm driving honda civic. My 09 S has a very flat bog and delay in normal mode right off the bottom. I also have the hesitation/miss from time to time at 2800 rpm. For PCNA to say that's "normal" or "some cars just do that" is BS. In normal mode unless you're really trying make a smooth shift from 1st to 2nd or running it up to 5k rpm to put your shift point above the 2800 rpm range, then it almost always results in a rough shift. Not so much in Sport mode, but that typically shoots you a little higher in the rpm range to get past that 2800 range.

Is any of this a HUGE deal no. Is it annoying...YES. The 997.1 cars do not drive like this in any way shape or form. Leads me to believe it's a DFI thing. It would be nice if they could figure it out with a simple remap, varicam timing, something, but it appears if it doesn't throw a code, they're not going to address it.

Petza914

That clutch switch would also come into play on every gear change. Have you just finished a shift at the RPMs where you say the lag occurs. With the switch enabled, it felt to me like the clutch wasn't engaging quickly enough; disabled, it drives like a cable clutch instead of a hydraulic one - jerky if you mess up the timing, but very smooth and direct otherwise.

wheeler

So there are two wires that go into the clutch switch? You just join those together? Sounds like you are jumping one wire to the other and leaving them connected to the switch as they already are?

Bruce In Philly

This was not the case on my 2000 Boxster S. I was having launch problems and it was the clutch switch. The only manifestation of a problem was launch from a dead stop and I had no other symptoms whatsoever.

I pulled the bad switch apart, and one of the metal "sides" had a hole worn straight through. Replacing the switch returned the car to normal operation.

The way the Porsche tech diagnosed the problem was using the Porsche computer which showed a fault on that switch. This fault, however, was not severe enough to light the dash. The tech assumed (actually guessed as he really didn't know) that the traction control system was being temporarily confused. The TC system has ignition retardation and then gas cutting in its algorithm.

By the way, this switch has nothing to do with starting the car... this is a large plunger switch that sits under the dash (sort of) and is only tripped when the clutch pedal is completely up and at rest against the stopping metal plate (where the switch resides). It is a $20 part.

http://www.pelicanparts.com/techarti...l_Switches.htm

Peace
Bruce in Philly