Last week I did some VAGCOM logs and found out that I have huge difference between CPU requested and actual pressure (block 115) especially in low revs (2000-4000).

I have checked all pipes to intercoolers as well however could not find any leak :? . Have tried geniune new N75 and also new geniune MAF - still same - very poor boost in low revs, at peak I have about 1bar = 15 psi but if you check reading from Vagcom you can see that requested boost is much higher than actual.
Below are VAGCOM logs of blocks 003, 115 and 118. N75 is exactly same as before and pressure as well.

Any idea what could be wrong?


'003
Engine RPM Air Mass Flow

/min g/s
1640 9.92
1800 27.08
2000 31.5
2240 38.03
2520 43.11
2760 48.92
3000 59.33
3320 72.81
3640 84.33
4000 105.53
4440 132.14
4840 156.64
5280 168.61
5720 181.11
6040 185.31
6400 188.06
6720 187.5
6920 187.53
7120 173.78

'115
Engine Speed Load Cmd Pressure Press @ Intercool

/min % mbar mbar
2160 84.2 2230 1050
2400 88.7 2330 1130
2640 94 2370 1170
2920 101.5 2350 1230
3240 109.8 2370 1320
3560 118 2400 1440
3920 133.1 2450 1590
4280 151.9 2440 1770
4720 170.7 2370 1990
5200 171.4 2390 2030
5640 167.7 2400 2010
6000 170.7 2300 1980
6320 161.7 2240 1970
6640 151.1 2130 1930
6960 132.3 2050 1970
7120 60.9 990 1920

'114
Spec. Load Load Correction Actual Load N75 Duty Cycle

% % % %
127.1 125.4 12.8 0
127.1 125.4 72.9 87.5
140.6 138.8 77.4 87.5
166.9 165.7 84.2 87.5
178.2 176.1 88.7 87.5
182.7 180.6 91.7 87.5
185.7 183.6 97.7 87.5
188 186.6 104.5 87.5
191 189.6 115 87.5
191.7 192.5 127.1 87.5
191.7 194 142.9 87.5
191.7 195.5 161.7 87.5
191.7 194 169.9 87.5
191.7 192.5 165.4 87.5
186.5 185.1 160.9 87.5
172.9 171.6 155.6 87.5
165.4 164.2 150.4 87.5
159.4 158.2 141.4 87.5
159.4 155.2 142.9 84.7

diverter valve? test it if you haven't.

How can I test it? I believe it is HX hyperboost DV - it was on the car when I bought it.

pull it off, compress it, hold finger on nipple and let go. It should create suction and stay up.

I just test it, it stayed there....

credit to CincyTT - check block 032 with VAG COM. Fuel trims negative more than 5% indicate likely boost leak. http://www.ross-tech.com/vag-com/cars/fuel-trim.html

I didn't mention it but I have already done it.

There are logs:

'032
Idle Value Part Throttle Value

% %
0.4 -4.7
0.4 -4.7
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -3.1
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7
0.4 -4.7

I also have done 032 log and multiply by 14.7:

Group B: '031
Engine RPM O2S1 Voltage O2S2 Voltage x 14.7

/min
2240 0.945 0.992 14.5824
2440 0.953 0.945 13.8915
2680 0.922 0.914 13.4358
2920 0.906 0.899 13.2153
3240 0.899 0.899 13.2153
3520 0.883 0.883 12.9801
3840 0.828 0.828 12.1716
4240 0.789 0.813 11.9511
4600 0.813 0.813 11.9511
5000 0.805 0.813 11.9511
5440 0.805 0.805 11.8335
5880 0.797 0.797 11.7159
6200 0.782 0.797 11.7159
6560 0.797 0.797 11.7159
6840 0.805 0.797 11.7159
7000 0.797 0.797 11.7159

Any idea?

nobody?

bump bump