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Fighting with P2177 (running lean)

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI

Finder

Ready to race!
Location
Canada
I believe it is at idle or cruising...what is the engine rpm at freeze frame of the code?

P2177, possibilities are...
1)Engine misfiring
2)Faulty O2 readings
3)Air leaks in the intake, post MAF
4)Low fuel pressure
5)Fuel injector failing
6)MAF sensor faulty
...so, you can eliminate 1, 3, 4, and 6 correct? Then you're left with 2 and 5. I'd choose to swap in a new O2 before injectors. If you do the new O2 and find nothing is corrected...you likely need injectors. When off and cleaning them, did you run them in for testing? If you believe them to be fine...then number 5 is now eliminated and you are left with just the O2. :thumbsup:

It is happening when cruising yes.
Code went away in the spring as fuel trims dropped below 20. Car still is running lean (currently at 12) but no CEL anymore.
1) no misfires
2) O2 sensor was the second part I replaced
3)possibly, but nothing showed up during several smoke tests and pressure tests
4)never had low fuel pressure and I have replaced all fuel pumps, sensors, filter (huge waste of money)
5)I don't think it applies as I'm not getting misfires. I have pulled and cleaned the injectors recently when I cleaned the intake valves.
6)MAF was actually the first part I replaced when all this started.

The car runs OK now as I guess it can compensate pretty well at 12 LTFT. We'll see what happens when it gets cold again.
 

tedted

Newbie
Location
CA
my p2177 went away! it was my front 02 sensor. Car drives much better now! I still am getting the +20% in my LTFT though...

see yall in the p0171 thread!
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
2) O2 sensor was the second part I replaced
Which O2? 1st or second one? ←Sorry, :yikes: but need to know if you replaced the wrong one since not specified.

My LTFT is recently been at 12% to 13%. My low pressure actual drops below 4 bar, to 3.5 bar, from 6k rpm to redline. Just installed the torqbyte pm3 today...gonna see what the pressure data shows with the oem lpfp before swapping in my TTRS lpfp. Since this began...my high pressure request has dropped from 140 bar to 110 bar. But before I did the pm3 install, I took all WG preload off and max boost went down to 20.5 psi...this allowed the high pressure request to go up to about 125 bar. We'll see if pressures get restored and the LTFT drops even more from where it's been.
 

Finder

Ready to race!
Location
Canada
First O2 sensor, obviously :wink:
 

tedted

Newbie
Location
CA
My p2177 is showing up again, which is weird because it didnt for a week or so and instead a p0171 was showing up. LTFT still gets maxed at 25% within 10-15min after clearing a CEL.

1)Engine misfiring--- havent had a misfire in months

2)Faulty O2 readings--- readings are fine (have a new front 02 sensor)

3)Air leaks in the intake, post MAF--- local mechanic has been smoke testing for almost a year and hasnt found anything. (the code first popped up when they did the k04 install and we've been chasing it since)

4)Low fuel pressure--- stays above 4bar

5)Fuel injector failing--- can I do a vcds to check this? I dont misfire

6)MAF sensor faulty--- replaced with a new one (another issue is I only pull in at max 230G/s and k04s are supposed to pull way more?)
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
I do not know of a way to check injectors. They can be pressure tested at some automotive machine shops such as NAPA, but that still doesn't test for proper spray volumes and patterns. I'm going to replace my injectors soon...and then take the old ones in for testing and rebuild...unfortunately, the solenoids do not get replaced when this is done. So if they aren't spraying properly, you're screwed...but 4 to rebuild and test is just $100.
 

tedted

Newbie
Location
CA
My vcds shows p2177
My Torque app shows p0171


If my LTFT goes up to 25%, my STFT balances +/- and my AFr stays at 14:1 does that mean my B1S2 (2nd 02 sensor) should be showing a high value like more than .5v constantly? Right now at idle it bounces from .1v-.7v
 
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ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
My vcds shows p2177
My Torque app shows p0171


If my LTFT goes up to 25%, my STFT balances +/- and my AFr stays at 14:1 does that mean my B1S2 (2nd 02 sensor) should be showing a high value like more than .5v constantly? Right now at idle it bounces from .1v-.7v

Generally, the V's in the post-cat O2 fluctuates/"pulses in waves" from 0.5 V to 0.7 V...but will go down in the waves from 0.5 V if lean or up in the waves from 0.7 V if rich. Yours is likely lean @ idle as well.

The LTFT of +25%..is this @ Idle(group 032-block 1) or Off Idle(group 032-block 2)? I assume it is block 2 because we've spoke via email. This means there is an imbalance while driving around. Could be a bad injector or pre-cat O2 sensor if lean...would include coils, plugs, or compression if correction was for running rich. But, if seeing a lean condition @ Idle as well...this could also be a cause for a lean correction when Off Idle...possibly ruling out those other possible causes for lean when Off Idle. Another situation is incorrect injection timing...but you'd need to take that up with the tuner. What is your correction in group 032 block 1? I believe within ±1.5% is the optimum range...need to go out and hover over the block on the laptop in order to get this range.
 
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tedted

Newbie
Location
CA
from the last log I did, the 032// block 1 goes from -1.3 to 1.9 during various runs, so that looks close enough within range.
block 2 goes up to 25%

going back to the P codes, its weird because each obd scanner picks up their respective code but they dont pick up each others (aka, vcds doesnt pick up p0171 and torque doesnt find p2177)

I have already replaced the front 02 sensor. The only 2 things left to do replacing parts wise is the booster hose that paul@ dapauto talks about here https://www.youtube.com/watch?v=67TjF-sXxkA and the rear 02 sensor (but i dont think thats necessary for this code).

I want to take the car back to the shop who installed the k04 (which got this whole CEL started) but they cant get me in until next month.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Data in group 032 block 1 shouldn't jump around...if you are just having it sit at idle(why data in block 1 is for "@ Idle") and looking at the correction data. The value may change as you sit there watching it, but it takes time to do so...again "@ Idle". Group 033 block 1 will fluctuate up an down as it idles...but that value will only change drastically as it idles if needed and the data in 032 block 1 will adjust.

Once you see the data in group 032 block 1 near zero when idling...and the data in block 2 is +high, this suggests no vac line leak, but rather an insufficient fuel delivery or an exhaust leak...which is very likely and possible.
 

tedted

Newbie
Location
CA
im watching vcds right now.
032 block 1= -1.3%
block 2= 24.6%

033 block 1= -2.x% to 2-3%
block 2= 1.4x

I also checked every single scan I did since getting k04'd and it seems the p2177 comes on around 2500-3k rpms (durr right "off idle").
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Still thinking if there's a leak between the turbo and 1st O2 sensor. Need to eliminate this. When installed the K04, who did it and have you inspected the DP to turbo? Is there any cracks in the DP welds...is everything tight?

The rich at idle but then lean when off idle suggests either a leak in exhaust or poor fuel delivery. Doesn't mean it can only be a plugged injector.
 

Finder

Ready to race!
Location
Canada
Decided to scan my car again yesterday.
There was no CEL but I did found three P2177 faults (intermittent), last freeze frame was 2 weeks ago at 3072 rpm.
LTFT is at 18.
Looks like the "fun" is about to start again. :mad0259:
 

tedted

Newbie
Location
CA
I notice not alot of you guys run a DV relocation kit? (or at least I dont see it in your sigs)

I have a APR k04. I am using the unitronic relocation kit and a cts turbo block off plate.
 
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