Fuel Trim Problem

[WadGTI]

Hi folks,

Everytime I get rid of a fault another comes back in its place..really getting me down now 

Anyways, I have one fault only on the engine block which is perhaps good.
 
1 Fault Found:
17536 - Fuel Trim: Bank 1 (Mult): System too Lean
        P1128 - 35-10 - - - Intermittent

I have cleared the code (came back). done a TB reset (then cleared code) and has come back. The car does have power though and boosts. I also got a refurbed bosch MAf last week as I had MAF code too. Anyways I have took some readings on blocks 002 and 032 on VAGCOM tonight.

I won't post all off it as there lots, but the ones I think are important are -

 
Group A:   002         
   Idle speed   Engine load   Inj. period   Air mass in
TIME   700-820 rpm   15-25%   2.0 - 4.0 ms   2.0-4.5 g/s
STAMP    /min   %    ms    g/s
0   720   15.8   2.04   2.31
0.4   720   16.5   2.04   2.47
0.8   760   16.5   2.04   2.42
1.2   720   15.8   2.04   2.33
1.6   720   15.8   2.04   2.36


52.61   5080   108.3   14.28   107.72
53.11   5440   115   14.96   120.58
53.51   5760   124.1   16.32   136.06

From what I can tell from online is that 136 is about right for the AUQ (bhp x 0.

The 032 codes readings are strange though!. Everytime time stamp has the same value from start to finish.

Group A:   032   
   Idle O2 Adapt   Run O2 Adapt
TIME   -10-10%   -10-10%
STAMP   %   %
0   -2.1   21.1
0.4   -2.1   21.1
0.9   -2.1   21.1
1.31   -2.1   21.1
1.81   -2.1   21.1

At a guess, is my o2 sensor buggered?. These logs were taking with the fault code still stored and all readiness tests at passed. The car was overfueling for a while and thinking it had maybe damaged the sensor.

Thanks folks

[WadGTI]

Any suggestions guys as I can pick up the o2 sensor(s) today.

Thanks

[rio_gti]

any motorfactors but go bosch 

[WadGTI]

any motorfactors but go bosch 

Thanks Rio. Have been on ECP website and can get the bosch sensor for £72 all in which is a cracking price as VW and TPS wanting £140+ for it.

Just hoping that the above symptons point towards the 02 sensor as I have been spending too much money on it recently and fund are getting short.

THe timing belt fund is gone too lol 

[WadGTI]

One of my mates is going to test my emmisions after work.

Does any know if this will clearly point in the direction of the o2 sensor if its faulty?

Thanks
Liam

[WadGTI]

Ok....so I had the emissions tested and it passted everything. (this was with the fault code still stored and it was not in learn mode).

I took a run out just now and measured the following. Can anyone tell me whats going on here??

Sorry guys, I tried to edit this to make it more readable but it just aint doing it.

Group A:   032            Group B:   002            Group C:   033   
   Idle O2 AdaptRun O2 Adapt              Idle speed   Engine load   Inj. period   Air mass in      PreCat O2 Reg   PreCat O2 V
TIME   -10-10%   -10-10%           TIME   700-820 rpm   15-25%   2.0 - 4.0 ms   2.0-4.5 g/s   TIME   -10-10%   0-1V
STAMP   %   %         STAMP    /min   %    ms    g/s   STAMP   %    V
1.14   0.9   2.3                         0.34   760   15   2.04   2.25   0.72   -5.5   1.48
2.55   0.9   2.3                         1.65   720   15   2.04   2.22   2.15   0   1.56
3.76   0.9   2.3                         2.95   720   15   2.04   2.25   3.35   -6.3   1.58
4.96   0.9   2.3                         4.16   760   15   2.04   2.28   4.56   -6.3   1.5
6.18   0.9   2.3                         5.36   720   16.5   2.04   2.42   5.76   -0.8   1.56
7.59   0.9   2.3                         6.68   1120   30.1   3.74   5.61   7.17   0   1.58
8.88   0.9   2.3                         7.99   1320   41.4   5.78   12.33   8.48   10.2   1.22
10.1   0.9   2.3                         9.28   2120   39.8   5.44   17.03   9.7   15.6   1.54
11.3   0.9   2.3                         10.5   1600   51.9   7.14   17.97   10.9   3.9   1.66
12.51   0.9   2.3                         11.7   2040   33.8   4.08   8.39   12.1   10.2   1.54
13.81   0.9   2.3                         13.01   2000   12.8   0   5.36   13.41   0   4
15.03   0.9   2.3                         14.23   1960   25.6   4.42   10.89   14.63   0   0.74
16.23   0.9   2.3                         15.43   2000   12   1.7   4.89   15.83   0   1.54
17.44   0.9   2.3                         16.63   1880   13.5   0   5.14   17.04   0   4.2
18.74   0.9   2.3                         17.94   1760   19.5   3.4   6.81   18.34   0   0.42
19.95   0.9   2.3                         19.15   1800   36.8   4.42   13.17   19.55   8.6   1.6
21.15   0.9   2.3                         20.35   1960   18.8   2.38   5.67   20.75   2.3   1.34
22.46   0.9   2.3                         21.55   1920   36.1   5.1   15.25   21.97   7.8   1.6
23.66   0.9   2.3                         22.86   2360   71.4   10.54   36   23.26   20.3   1.7
25.09   0.9   2.3                         24.08   3200   84.2   11.9   52.53   24.59   21.1   1.58
26.38   0.9   2.3                         25.6   4480   99.2   14.28   84.44   26   17.2   1.16
27.6   0.9   2.3                         26.78   5440   109   14.62   114.61   27.2   5.5   0.92
28.9   0.9   2.3                         28   6360   112   17.68   133.11   28.42   0   0.04
30.21   0.9   2.3                         29.31   4440   13.5   0   9.44   29.81   0   4.14
31.42   0.9   2.3                         30.61   4560   12   0   9.44   31.01   0   4.18
32.72   0.9   2.3                         31.92   4040   12   0   9.53   32.32   0   4.22
 

[WadGTI]

I found this on vortex -

Block 033 - Pre-Cat Oxygen Sensor Control

 - Go to Block 033. The value in Field 1 represents the pre-cat oxygen sensor control. The value should fluctuate at least 2% in the -10 to +10% range.

My readings shoot above 20 as above.

Just to add here, there is no leaks in any part of the exhuast system, charge pipe looks good, From what i can tell/hear no vacc leaks (other that getting a smoke test which I am planning on doing shortly), the car has boost, pull very well. The o2 sensors have never been changed ever by the looks of them too.

It has just came to my that the SAI leaks or is loud either way when on (cold start). Could this act like a vaccum leak even when off?

Thanks

[WadGTI]

Some boost figures

Engine Speed   Engine Load   Spec. Boost   Actual Boost
700-6800 RPM   15-150%   990-1800 mbar   <=1800 mbar
 /min   %    mbar    mbar


30.89   4240   93.2   1630   1560
31.69   5000   107.5   1670   1590
32.68   5880   123.3   1630   1650
33.5   6480   115   1570   1590
34.31   5840   11.3   1020   1190
35.31   4640   12   1020   1060


From what I can tell, its boosting aorund 9 psi (ish) around 6k revs?

[Wazzzer]

system too lean is usually an air leak in after the MAF...

and yes it's hitting around 9psi. Is that with your foot flat to the floor?

[WadGTI]

system too lean is usually an air leak in after the MAF...

and yes it's hitting around 9psi. Is that with your foot flat to the floor?

Thanks Wazzer. Yeah your right.

I found 2 leaks  - pcv breather that goes into the tip  (the plastic extension on the pipe was torn at the seem) and one of the vac reservoir pipes that I blocked off for the n249 bypass was still leaking. - Used the spray bottle method and was surprised with the results lol

Picking up new breather tomorrow and the full n249 removal tomorrow. Hopefully will be air tight now and will get better maf readings

Only thing is, I'm not sure if I can run the following vac line (Manifold -> N112 -> CheckValve/SAI)??

My current vac setup is DV -> T Piece -> FPR/Manifold - Runs great and have no fulter - Good Noise too. Not really wanting to mess with this vac line as it works well in my view.

Yeah, 9 psi on WOT run.

Cheers