Fighting with P2177 (running lean)

[larcic]

you are only running a little lean if at all. the 20%+ correction is probably what is giving you the cel. I think you get a cel when it goes above 20% but not sure. if you are 100% sure there are no leaks it could be fuel related...have you checked fuel pressure?...the ecu can correct for lean conditions(by adding fuel) up to 25%

 

[Finder]

Fuel logs (HPFP and LPFP) are in my top post. I don't see anything wrong there myself.

 

[larcic]

I'm not sure where else to look then...might need to take this to vw specialist...you could also try installing the stock intake for giggles to see if it makes a difference

 

[Finder]

I've ran this intake for a few years now without issues. It can't be it.
And yes I have a feeling I will have lots of "fun" with this for a while.
Thanks for trying..

 

[clockwise33]

Did you work on the car prior to this condition coming about?

 

[Finder]

Replaced the fuel filter and valve cover sometime in NOV-DEC, not sure exactly when but the car was fine after.
I started getting CELs in January.

I've had P2177 a few times last winter and two winters ago too (so only when cold) but I would clear them and be good for weeks. Never had it in spring-summer-fall. I always thought it might be just some frost on the MAF.

 

[clockwise33]

I have found that most of my gremlins over the years have come from aftermarket parts. Try to eliminate the Eurojet DV relocate and IE PCV block off as possible causes.

Also check the brake booster hoses that attach to the vacuum pump. It is common for these lines to crack with age. You will not find a leak in these hoses by smoke testing because there is a check valve preventing boost from entering the vac pump and brake booster system.

Link to said hoses: https://www.ecstuning.com/b-genuine-volkswagen-audi-parts/brake-booster-hose/1k0612041gm/

 

[larcic]

just because it started getting cel recently doesnt mean it wasnt always there...remember a cel wont come on until 20% partial but you want it to be less than 10%

 

[Finder]

I can put back the stock PCV but I can't remove the DV relocate as I run a K04 which doesn't have a DV port.
I've replaced all brake booster hoses no more than 2 years ago when I was chasing an EVAP leak, but I will have another look at them.

 

[clockwise33]

Try spraying the front and rear pcv and brake booster hoses with brake cleaner/carb cleaner at idle. You won't see leaks in either of these spots with smoke because there are check valves.

 

[Finder]

Ok, I will try this when I get home today.

 

[Finder]

So I've sprayed brake cleaner covering all areas from the top of the engine (I haven't went under the car to spray the turbo pipe, intercooler hoses..) but I couldn't find anything. No rpm spikes.
I scanned the car last night and found a new code though:
P310B/012555 - Low Pressure Fuel regulation: Fuel Pressure Outside Specification

I will try this tonight to see if it's the G410 sensor or the in-tank fuel pump.

 

[larcic]

nice, low fuel pressure from the in tank pump can cause this. have you replaced your fuel filter recently?

 

[Finder]

Some updates:
I tested the G410 sensor using the method I've found online and the pressure difference between the low side (6.5 bar) and high side (6.4 bar) is 0.1 bar which is within spec. I also have the latest sensor version (K). All this means the sensor is OK.

I've done intake smoke and pressure testing two more times this week, used the brake cleaner method again and I just can't find any leaks.
Yesterday I removed the intake, DV reroute piping, throttle body pipe and checked for cracks. Re-tightened everything back.
The P310B code never came back and it's been a week since. I know that the day before it happened it got really low on gas before I could reach a gas station, maybe the code got triggered then.
I don't think the in-tank pump is the problem, I went through another tank of gas and the code hasn't returned. Plus the fuel pressure on the high side meets the request based on my logs. I assume if the tank pump is bad I would see issues there, correct?
I would hate to spend the money for a new pump and not solve this as I already replaced 3 sensors for nothing.
Meanwhile I'm still driving with a CEL and fuel trim (long) at 22.3% :mad0259:

 

[Finder]

Here is the log for in-tank pump output (Group 103 field 0):

RPM Fuel pressure (mbar)
1840 4845
1840 4845
1840 4870.5
1840 4870.5
1840 4845
1840 4845
1840 4870.5
1880 4845
1960 4819.5
1960 4870.5
2040 4870.5
2080 4870.5
2160 4870.5
2280 4870.5
2360 4896
2440 4921.5
2520 4896
2600 4896
2760 4845
2840 4768.5
3000 4717.5
3080 4666.5
3240 4590
3360 4590
3560 4590
3680 4564.5
3800 4513.5
3920 4488
4040 4513.5
4200 4488
4320 4437
4440 4386
4560 4335
4680 4284
4800 4284
4920 4309.5
5000 4335
5120 4309.5
5200 4284
5320 4207.5
5440 4182
5520 4156.5
5600 4182
5720 4156.5
5800 4080
5920 4003.5
Pump duty cycle starts at 46.7% and ends at 83.5% during the run above.

Does anyone know if all these numbers are ok?