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p0172 code, MAF / MAP sensor?

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Old Sep 27, 2018 | 10:21 PM
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Default p0172 code, MAF / MAP sensor?

Hi all, was hoping for some insight.
I have a 2013 C2, 3.4L. 29k miles

2 weeks ago I did the Gundo hack. I have don't the same mod on my 996's and 997 with similar results.

Yesterday, I threw a code P0172 and the display said Fault engine control Possible to drive on.
P0172 translates to System too rich bank 1
I cleared the code and the same one came back later today after driving ~30 miles. The idle also seems a little more rough than usual.
Any idea on what could be causing this? Any relation to recently doing the Gundo hack?

Thanks

From what I understand there is no MAF sensor in this car, just a MAP sensor - is that correct?
Normally my first instinct would be to clean the MAF, but not sure what to do in this situation. Any thoughts?
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Old Sep 28, 2018 | 04:58 PM
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Correct that there is no MAF sensor, no wire in the flow path. Air mass is now calculated by the ECU using other data such as throttle position, air temperature, RPMs, etc. There is nothing in the intake path to clean... other than the air filter of course. Sorry, but I have no other solid input as to what would cause this other than maybe a leaky injector or a misfiring spark plug.
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Old Sep 28, 2018 | 10:26 PM
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arter's Avatar
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Clean, replace, or swap side to side the O2 sensor.?
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Old Oct 17, 2018 | 07:39 PM
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The car is also idling a little rough but when I bring the RPMs up a slight bit it is fine.
I tried some techron fuel cleaner without any luck.
What would be a way to determine if I have a leaky injector vs bad o2 sensor?
I would assume a bad spark plug would give a misfire code but I suppose its possible
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Old Oct 17, 2018 | 08:50 PM
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I can't really say that my earlier guesses are the cause. I can't really speak to the high pressure injectors used in our cars, but in my experience in "normal" cars a leaky injector also results in a hard initial start since pressure is lost when it floods the cylinder a bit while the engine is turned off. This can be detected with a fuel pressure gauge showing pressure leaking down when attached to an access point of the injector lines on normal cars, but I certainly wouldn't attempt to self-diagnose our injectors due to the extremely high pressures involved. If you don't also have a hard start I doubt this is the problem.

I agree with you that a misfiring plug would also almost certainly result in a more appropriate error code, so I was probably wrong about that. I think it is probably something you'll need to seek professional help with, unless you want to try the O2 sensor change like arter suggested above, which isn't too tough to do. You could possibly even just replace it since I doubt it is terribly expensive (famous last words for Porsche parts).
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Old Oct 22, 2018 | 04:22 PM
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The plot thickens...
So I couldn't help but think this situation had something to do with my cent Gundo hack.
I went back to the muffler shop and had the car lifted up - There appeared to be soot around the clamps between the side and center mufflers. This likely indicates a leak so we took off the clamps and re-tightened them on both sides.
I took the car for a long spirited drive after that and everything was going great for 30 mins.
Then out of nowhere I get the error: PSM Loss Possible to drive carefully & Start/Stop operation deactivated & Fault engine control possible to drive on. The car also started to misfire at this time.
I turned the car off then on and everything cleared. This has never happened before.

I can my scanner on the car and there were no codes present.
But there were a handful of pended codes:
p0172- system too rich bank 1
p1382
p0301 - cyl 1 misfire
p0302- cyl 2 misfire
p0303 - cyl 3 misfire

Not sure where to go from here...Does anyone have any thoughts?
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Old Oct 22, 2018 | 10:08 PM
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Here's my concern for you: Significant misfiring can fairly quickly ruin a catalytic converter and replacing that, on top of the cost of fixing the core problem, gets really expensive quick. On a road trip with a prior Corvette it developed a misfire in the middle of nowhere but I just kept going. The result was I ended up fusing the pellets in the converter thereby clogging up the exhaust flow and ended up having to buy a new one.

I'd recommend heading on over to a reputable shop with experienced Porsche mechanics and pay just the cost of fixing the core problem at this point.
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Old Nov 8, 2018 | 11:43 AM
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I disconnected/cleaned my MAP sensor without any luck.
Will try new map sensor and new spark plugs this weekend.


Just to confirm, the MAP sensor is under the front bonnet near the brake vacuum lines correct? as shown in this video:
I just found it a bit peculiar it is not located anywhere near the intake plenum/throttle body like it was in the 997. Is there another MAP sensor somewhere in this car?
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Old Nov 8, 2018 | 11:56 AM
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No, that video is completely wrong! Your intuition was right on that. It's monitoring the brake boost pressure. I looked up that part number out of curiosity. It appears to be a multi-purpose pressure sensor that is used on some cars for a MAP sensor and on others for brake pressure monitoring.

I'm trying to say this constructively: I'm of the opinion you should take the car to a certified Porsche mechanic or you'll end up doing experiments that are going to cost you more in the long run or end up doing harm to the engine with this continuing problem. There's no way a spark plug is causing multiple cylinders to misfire and the chances of them all failing together on one bank are close to nil.
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Old Nov 8, 2018 | 12:19 PM
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i doubt is the plugs or anything else. my guess would be the 991 is diff compared to the 997 and the 996 and the Gundo mod could be throwing codes in our exhaust system.
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