AKN: Partial Power Outage Affects Service

Hello everyone,

'I am experiencing some performance issues with my AKN (presumably a type of equipment). This manifests as follows when accelerating:'
Around 2400 RPM, the turbo kicks in, and acceleration is momentarily good. However, just below 3000 RPM, you can clearly feel the decreasing power (as if the power is being reduced), after which acceleration improves again.

I hope I logged the correct data...

Thank you.

Saturday, August 21, 2004, 07:59:38.
4B0 907 401 C 2 0000SG D61

Group A: '008
Group B: '009
Group C: '011
u/min Injection amount Injection amount Injection amount Injection amount Injection amount Injection amount Injection amount u/min Absolute pressure Absolute pressure Working cycle
TIME TIME TIME
MARKER STAMP /min mg/R mg/R mg/R STAMP mg/R mg/R mg/R mg/R STAMP /min mbar mbar %
1.23 766 0 31.7 22.3 0.37 0 0 0 99 0.8 766 1040 1030 74.2
2.61 766 0 31.7 22.3 1.67 0 0 0 99 2.11 766 1040 1030 74.2
3.94 766 0 31.7 22.3 3.06 0 0 0 99 3.5 766 1040 1030 74.2
5.25 766 0 31.7 22.3 4.39 0 0 0 99 4.8 766 1040 1030 74.6
6.65 766 0 31.7 22.3 5.75 0 0 0 99 6.19 766 1040 1030 74.2
7.95 766 0 31.7 22.3 7.07 0 0 0 99 7.51 766 1040 1030 74.2
9.37 1253 19.8 38 22.9 8.44 0 0 0 99 8.87 905 1183 1030 89.6
10.75 1531 25.7 39.2 24.5 9.87 18.8 0 0 99 10.3 1183 1265 1153 84.4
12.17 2065 0 37.3 36.7 11.24 26.7 0 0 99 11.73 2390 1459 1652 48.1
13.49 1415 48.3 38.9 25.4 12.6 9.4 0 0 99 13.05 1763 1081 1397 55.2
14.81 1926 51.1 37 35.1 13.92 55.2 0 0 99 14.37 1694 1928 1408 82.1
16.25, 2761, 46.1, 38.6, 45.8, 15.31, 48.6, 0, 0, 99, 15.75, 2459, 2020, 2193, 42.6
17.64 3596 43.6 38.9 36.7 16.69 45.2 0 0 99 17.17 3341 2101 2489 32.4
18.95 2413 47.1 38 37.6 18.06 0 0 0 99 18.51 3248 1244 1275 45
20.31 2877 44.9 38.9 43.9 19.39 46.4 0 0 99 19.81 2738 2040 1928 49.3
21.63 2204 0 37.6 27 20.75 33.6 0 0 99 21.18 2877 1183 1591 46.2
23.01 2018 0 37.3 22 22.08 0 0 0 99 22.5 2065 1091 1071 50.1
24.39 1949 0 37.3 21.6 23.44 0 0 0 99 23.89 1972 1081 1051 51.3
25.83 1926 42.4 37 27.6 24.88 3.1 0 0 99 25.36 1902 1316 1102 71.8
27.12 2065 49.9 37.3 39.8 26.25 50.5 0 0 99 26.7 1995 1989 1571 61.2
28.45 2227 48.6 37.6 43.6 27.58 49.6 0 0 99 28.01 2158 1999 1989 51.3
29.76 2390 47.7 38 46.1 28.88 48.3 0 0 99 29.34 2343 2009 2264 42.6
31.09 2552 46.7 38.3 38 30.22 47.4 0 0 99 30.64 2506 2020 1785 52.5
32.4 2714 46.1 38.6 40.2 31.52 46.7 0 0 99 31.96 2668 2030 1856 55.6
33.73 2877 45.5 38.9 41.4 32.86 45.8 0 0 99 33.28 2830 2040 1989 56
35.04 3039 45.2 39.2 42 34.16 45.5 0 0 99 34.61 2993 2050 2091 51.7
36.37, 3202, 44.9, 39.2, 41.7, 35.51, 44.9, 0, 0, 99, 35.92, 3155, 2071, 2091, 52.1
37.74 3364 44.2 39.2 41.7 36.8 44.5 0 0 99 37.31 3318 2101 2111 52.5
39.23 3526 41.1 39.2 41.1 38.24 44.2 0 0 99 38.75 3457 2122 2132 50.1
40.67 2645 0 38.3 28.9 39.72 0 0 0 99 40.16 2900 1734 1346 68.3
42.04 2575 0 38.3 27 41.1 0 0 0 99 41.58 2598 1153 1214 48.9
43.34 2390 0 38 25.4 42.49 0 0 0 99 42.92 2436 1132 1163 50.1
44.69 2204 0 37.6 23.5 43.8 0 0 0 99 44.24 2227 1091 1122 50.1
46.05 2134 0 37.6 22.9 45.16 0 0 0 99 45.6 2158 1091 1091 50.1
47.43 2065 0 37.3 22.3 46.54 0 0 0 99 47.01 2088 1091 1081 50.1
48.88 1995 0 37.3 22 47.92 0 0 0 99 48.37 2018 1081 1071 50.1
50.17 1949 0 37.3 22 49.31 0 0 0 99 49.75 1949 1081 1061 52.1
51.48 1926 42.4 37.3 22.3 50.62 0 0 0 99 51.07 1879 1081 1061 55.2
52.83 1926 50.8 37 35.8 51.92 51.1 0 0 99 52.38 1902 1979 1408 75
54.12 1067 0 34.5 24.2 53.24 0 0 0 99 53.68 1601 1081 1326 55.2
55.5 2575 0 38.3 24.2 54.59 0 0 0 99 55.08 2227 1091 1040 50.1
56.94 2088 0 37.3 24.2 55.96 0 0 0 99 56.44 2204 1091 1163 50.1
58.3 2134 49.3 37.6 30.1 57.38 0 0 0 99 57.82 2111 1989 1132 70.2
59.7 2482 47.4 38 43.6 58.81 48.6 0 0 99 59.26 2343 2009 1816 53.3
61.01 2854 45.8 38.9 38.9 60.12 46.7 0 0 99 60.56 2714 2040 2315 41
62.42 3271 44.5 39.2 40.2 61.5 45.2 0 0 99 61.94 3132 2071 1897 52.1
63.82 3642 43.6 38.9 40.5 62.88 44.2 0 0 99 63.36 3526 2122 2081 54.4
65.24 3851 0 38.3 35.1 64.3 43.3 0 0 99 64.74 3874 2122 2142 50.9
66.68 1763 0 36.7 22.6 65.74 0 0 0 99 66.18 2413 1132 1214 50.1
68.04 742 0 31.7 21.6 67.12 0 0 0 99 67.6 789 1020 1071 76.1
69.44 742 0 31.7 22 68.48 0 0 0 99 68.99 742 1040 1040 75
70.8 742 0 31.7 22 69.85 0 0 0 99 70.36 742 1040 1030 75
72.1 742 0 31.7 22 71.25 0 0 0 99 71.7 742 1040 1030 74.6
73.48 742 0 31.7 22 72.55 0 0 0 99 73 742 1040 1030 74.6
74.83 766 0 31.7 22 73.95 0 0 0 99 74.4 766 1040 1030 74.6

Hello,

I'm having a bit of an eye twitch right now, but if I put that aside for a moment...
I couldn't quite decipher the exact numbers, but I think the last digits represent 'load' and 'set pressure,' and I would say that it has a significant overshoot.

16.25 2761 46.1 38.6 45.8 15.31 48.6 0 0 99 15.75 2459 2020 2193 42.6
17.64 3596 43.6 38.9 36.7 16.69 45.2 0 0 99 17.17 3341 2101 2489 32.4

Around approximately 2400 RPM, the turbo kicks in. Acceleration is temporarily acceptable, but just below 3000 RPM, you can clearly feel the decreasing power (as if the power is being reduced), and then acceleration improves again.


Hi Rene_S,

The turbocharger needs to start boosting much earlier. At 1500 RPM, the turbo should be developing its full torque. Unfortunately, your log is completely missing the mass airflow (MAF) values. Please provide another log with the following values included.

LMM, keyboard control for the VTG solenoid valve, boost pressure, and injection quantity.

This was all measured in the third gear, over a wider range of engine speeds.

hello Rene_s

In my case, the boost pressure is approximately 2050 mbar when measured at around 1700-1800 RPM.


If you only use group 11 for logging, the resolution will be better.

In the third gear, you should be able to see in the graph when the actual value lags too far behind the target value.

I suspect the EPW valve; if it's stuck, that could also explain the overshoots.


As a test, you can try swapping the valve with the one from the EGR system, but the connections are slightly different.

Good luck, Rainer. (A4, AKN)

Hello everyone,

Finally, the solution: A few weeks ago, I discovered air bubbles in the pre-filter leading to the ESP (Exhaust Gas Recirculation). My mechanic said at the time that this wasn't a problem, but if it got worse, I would have to replace the entire ESP unit.
However, this didn't put my mind at ease during the current troubleshooting process. So, I bought a new filter, and while installing it, I noticed that the fuel hose had been crushed by the inner part of the hose clamp.
With a shortened hose and a 20 km test drive, the problem seems to be resolved.

However, I cannot explain the error code 575, 'limit exceeded,' in this context. The error memory was empty after 20 km, and I will continue to investigate.

Okay, one more thing: What color is the N75 valve in your car, gray or black? According to the wiring diagram I have, the connector with the rt/ws and ws/rt wires should be plugged into it. In my car, it was plugged into the AGR valve (N5???). After I replaced the hoses, the Audi started running like my Mondeo with 300,000 km (approximately 186,000 miles).