Audi RS2

[AVP]

can you explain to me why it is going to retard a lot for ignition based timing?

[AVP]

in the acceleration amount values, is it the higher the number = the more fuel is added on pressing the accelerator pedal?

[AVP]

im going to try to recalibrate the TPS as well today and if idle does not respond i may go for the IAC/diode solution and play around with those settings.

i have noticed also that when stationary and on idle, if i press the accelerator and release it, that is also when the small dip in revs as well as 'missfire' like feeling is there. On datalogging i think it gets too lean on that time.I get lamda values of 1.5 something. So which way should i change the acceleration enrichment table to compensate?

here are some more tables:

here on the accel.enrichment the accel amoun (0) was 0.7 and i have used 0.3 but havent tried it yet.

[rob@vems.co.uk]

can you explain to me why it is going to retard a lot for ignition based timing?

If the current RPM is higher than target then the ignition based idle will retard in order to reduce the engine speed.

in the acceleration amount values, is it the higher the number = the more fuel is added on pressing the accelerator pedal?

Acceleration Bins is how quickly the pedal is pressed, and the Acceleration Amount is the length of time added to the injector's PW to add more fuel.
The recommended Acceleration Bins values are:

• (dv/dt) 1
[1](dv/dt) 5
[2](dv/dt) 20   
[3](dv/dt) 40

im going to try to recalibrate the TPS as well today and if idle does not respond i may go for the IAC/diode solution and play around with those settings.

TPS calibration is never a bad thing to do, although unless the TPS is over 2% (look at: Extras->Idle Settings and you'll see that TPS value for idle threshold(%) is set to 2)
calibrating it will not have any effect.  It should be 0% when the throttle is resting on the throttle stop.

[AVP]

right,
after calibration tps off was : 0 and TPS WOT was 255. So i entered those values on the basic settings screen.

today i tried the idle settings of the diode,but again i could not get the damn idle to settle @ 900 or 800rpm. Also when i turned the advance based idle off, it still didnt do much. On my spark table on idle i get the 2nd bin lighting up where i have 30.75 advance angle and that makes the idle with around 20deg. of advance as it sits between 700 and 1200rpm. However when i reduce that value to 18.75 for example i do get the idle to sit lower, BUT i get higher EGT on that setting.

Now how can i actually get the idle to listen to the commands i set???

I also made the change on the acceleration bins,

tell me something: is the highest the number, the faster the acceleration pedal responce? is that how it goes?

Also, is there any correspondence among the 4 bins and 4 accel.amounts? would the value of the 1st bin correspond to the value of the 1st accel.amount?

I managed anyway to get it a bit better on soft pedal depression,but on gear change,it still bumps no matter what numbers i have tried,

i also noticed that with the pedal depression on idle and stationary, while making those changes, it seems that EGTs are getting quite lower, which is not something that is happening with the motronic on similar circomstances!

[rob@vems.co.uk]

Those numbers sound incorrect to me, have a read of this:
http://195.159.109.134/vemsuk/forum/index.php/topic,600.0.html

Is the throttle properly closed, or is it open a bit?  If its open, with the best will in the world you're not going to a low idle, if there is an idle adjustment screw you should:
Ensure that the ICV is closed.
Turn off the ignition based idle.
Reduce the idle speed using the adjustment screw.

This will then make cold idling difficult as the engine will not rev high enough - so you'd then need to get the ICV working properly.

Until you have the TPS spot-on you'll not be able to get the acceleration enrichment even close.
When you map the car you dont want acceleration enrichment on anyway.

Tuning is a very complex subject because of the huge number of variables that are in play, don't underestimate the amount of learning and experimenting that you'll need to do.

[AVP]

the issue here is the fact that the throttle body has not been tampered with or altered in any way from factory. So to have the screw altered should not be the solution, since others that have been using VEMS on 20V 5cylinder turbo engines, never had to go through that procedure themselves to achieve good idle.

When the throttle is completelly closed, it clicks.That is how motronic understands and receives that information to control idle.However on VAGCOM with closed throttle you always get a reading of 8 deg. angle for some reason, without that interfereing with how idle is managed by motronic.

Initially, mark had used numbers 23 and 240 for TPS. Calibration gave me 0 and 255. So why would those 2 numbers from calibrations be wrong?

on idle and on main screen the TPS gauge shows 0. ISnt that what it should show?


here is also a config file i have.im not sure if this was done when i did the calibration:

 MegaTune-generated Linear Throttle Calibration
; Written on 2009-05-15T18:57:42+01:00
;
;   Low ADC = 0    High ADC = 255
;
THROTTLEFACTOR:
         ; ADC
   DB     0T   ;   0
   DB     0T   ;   1
   DB     0T   ;   2
   DB     1T   ;   3
   DB     1T   ;   4
   DB     1T   ;   5
   DB     2T   ;   6
   DB     2T   ;   7
   DB     3T   ;   8
   DB     3T   ;   9
   DB     3T   ;  10
   DB     4T   ;  11
   DB     4T   ;  12
   DB     5T   ;  13
   DB     5T   ;  14
   DB     5T   ;  15
   DB     6T   ;  16
   DB     6T   ;  17
   DB     7T   ;  18
   DB     7T   ;  19
   DB     7T   ;  20
   DB     8T   ;  21
   DB     8T   ;  22
   DB     9T   ;  23
   DB     9T   ;  24
   DB     9T   ;  25
   DB    10T   ;  26
   DB    10T   ;  27
   DB    10T   ;  28
   DB    11T   ;  29
   DB    11T   ;  30
   DB    12T   ;  31
   DB    12T   ;  32
   DB    12T   ;  33
   DB    13T   ;  34
   DB    13T   ;  35
   DB    14T   ;  36
   DB    14T   ;  37
   DB    14T   ;  38
   DB    15T   ;  39
   DB    15T   ;  40
   DB    16T   ;  41
   DB    16T   ;  42
   DB    16T   ;  43
   DB    17T   ;  44
   DB    17T   ;  45
   DB    18T   ;  46
   DB    18T   ;  47
   DB    18T   ;  48
   DB    19T   ;  49
   DB    19T   ;  50
   DB    20T   ;  51
   DB    20T   ;  52
   DB    20T   ;  53
   DB    21T   ;  54
   DB    21T   ;  55
   DB    21T   ;  56
   DB    22T   ;  57
   DB    22T   ;  58
   DB    23T   ;  59
   DB    23T   ;  60
   DB    23T   ;  61
   DB    24T   ;  62
   DB    24T   ;  63
   DB    25T   ;  64
   DB    25T   ;  65
   DB    25T   ;  66
   DB    26T   ;  67
   DB    26T   ;  68
   DB    27T   ;  69
   DB    27T   ;  70
   DB    27T   ;  71
   DB    28T   ;  72
   DB    28T   ;  73
   DB    29T   ;  74
   DB    29T   ;  75
   DB    29T   ;  76
   DB    30T   ;  77
   DB    30T   ;  78
   DB    30T   ;  79
   DB    31T   ;  80
   DB    31T   ;  81
   DB    32T   ;  82
   DB    32T   ;  83
   DB    32T   ;  84
   DB    33T   ;  85
   DB    33T   ;  86
   DB    34T   ;  87
   DB    34T   ;  88
   DB    34T   ;  89
   DB    35T   ;  90
   DB    35T   ;  91
   DB    36T   ;  92
   DB    36T   ;  93
   DB    36T   ;  94
   DB    37T   ;  95
   DB    37T   ;  96
   DB    38T   ;  97
   DB    38T   ;  98
   DB    38T   ;  99
   DB    39T   ; 100
   DB    39T   ; 101
   DB    40T   ; 102
   DB    40T   ; 103
   DB    40T   ; 104
   DB    41T   ; 105
   DB    41T   ; 106
   DB    41T   ; 107
   DB    42T   ; 108
   DB    42T   ; 109
   DB    43T   ; 110
   DB    43T   ; 111
   DB    43T   ; 112
   DB    44T   ; 113
   DB    44T   ; 114
   DB    45T   ; 115
   DB    45T   ; 116
   DB    45T   ; 117
   DB    46T   ; 118
   DB    46T   ; 119
   DB    47T   ; 120
   DB    47T   ; 121
   DB    47T   ; 122
   DB    48T   ; 123
   DB    48T   ; 124
   DB    49T   ; 125
   DB    49T   ; 126
   DB    49T   ; 127
   DB    50T   ; 128
   DB    50T   ; 129
   DB    50T   ; 130
   DB    51T   ; 131
   DB    51T   ; 132
   DB    52T   ; 133
   DB    52T   ; 134
   DB    52T   ; 135
   DB    53T   ; 136
   DB    53T   ; 137
   DB    54T   ; 138
   DB    54T   ; 139
   DB    54T   ; 140
   DB    55T   ; 141
   DB    55T   ; 142
   DB    56T   ; 143
   DB    56T   ; 144
   DB    56T   ; 145
   DB    57T   ; 146
   DB    57T   ; 147
   DB    58T   ; 148
   DB    58T   ; 149
   DB    58T   ; 150
   DB    59T   ; 151
   DB    59T   ; 152
   DB    60T   ; 153
   DB    60T   ; 154
   DB    60T   ; 155
   DB    61T   ; 156
   DB    61T   ; 157
   DB    61T   ; 158
   DB    62T   ; 159
   DB    62T   ; 160
   DB    63T   ; 161
   DB    63T   ; 162
   DB    63T   ; 163
   DB    64T   ; 164
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   DB    66T   ; 169
   DB    66T   ; 170
   DB    67T   ; 171
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   DB    67T   ; 173
   DB    68T   ; 174
   DB    68T   ; 175
   DB    69T   ; 176
   DB    69T   ; 177
   DB    69T   ; 178
   DB    70T   ; 179
   DB    70T   ; 180
   DB    70T   ; 181
   DB    71T   ; 182
   DB    71T   ; 183
   DB    72T   ; 184
   DB    72T   ; 185
   DB    72T   ; 186
   DB    73T   ; 187
   DB    73T   ; 188
   DB    74T   ; 189
   DB    74T   ; 190
   DB    74T   ; 191
   DB    75T   ; 192
   DB    75T   ; 193
   DB    76T   ; 194
   DB    76T   ; 195
   DB    76T   ; 196
   DB    77T   ; 197
   DB    77T   ; 198
   DB    78T   ; 199
   DB    78T   ; 200
   DB    78T   ; 201
   DB    79T   ; 202
   DB    79T   ; 203
   DB    80T   ; 204
   DB    80T   ; 205
   DB    80T   ; 206
   DB    81T   ; 207
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   DB    81T   ; 209
   DB    82T   ; 210
   DB    82T   ; 211
   DB    83T   ; 212
   DB    83T   ; 213
   DB    83T   ; 214
   DB    84T   ; 215
   DB    84T   ; 216
   DB    85T   ; 217
   DB    85T   ; 218
   DB    85T   ; 219
   DB    86T   ; 220
   DB    86T   ; 221
   DB    87T   ; 222
   DB    87T   ; 223
   DB    87T   ; 224
   DB    88T   ; 225
   DB    88T   ; 226
   DB    89T   ; 227
   DB    89T   ; 228
   DB    89T   ; 229
   DB    90T   ; 230
   DB    90T   ; 231
   DB    90T   ; 232
   DB    91T   ; 233
   DB    91T   ; 234
   DB    92T   ; 235
   DB    92T   ; 236
   DB    92T   ; 237
   DB    93T   ; 238
   DB    93T   ; 239
   DB    94T   ; 240
   DB    94T   ; 241
   DB    94T   ; 242
   DB    95T   ; 243
   DB    95T   ; 244
   DB    96T   ; 245
   DB    96T   ; 246
   DB    96T   ; 247
   DB    97T   ; 248
   DB    97T   ; 249
   DB    98T   ; 250
   DB    98T   ; 251
   DB    98T   ; 252
   DB    99T   ; 253
   DB    99T   ; 254
   DB   100T   ; 255

[rob@vems.co.uk]

I see what you are saying - if the TPS calibration showed the throttle as being 8% open then the Idle control will never come in, because the the threshold is set to 2% (as I wrote in a previous post).
The calibration wizard never seems to work properly - that thread explains how I calibrate a TPS.
You want the VEMS to read 0% when the throttle pedal is up, and 100% when the throttle pedal is down.

[AVP]

Thanks for that Rob.

i fixed that now!

under tuning/acceleration dotrate/% you get the scale you need to tune for accel.enrichment.

i seemed to be able to fix accel.enrichment faster through there,but all changes i made there, were not impleneted in the settings window after that. Should they be there,or is tuning something you see real time and once you are happy with what you have,you go back to the window and put the new values in?

vasilis

[rob@vems.co.uk]

Don't forget to Burn to ECU after your changes.

[AVP]

good think you mentioned that. it seems that when i do changes, ECU responds withough me having to burn to ecu. I do press the button,but i can see the responce from the engine even before i do that.

so is the burn to ecu always needed?

[AVP]

also, quick question:

i realise what PID means,

can someone tell me what the integral increase/decrease means, as well as the deadband for integral and IAC? (rpm)


thanks

[rob@vems.co.uk]

The best explaination I've seen is this:
http://en.wikipedia.org/wiki/PID_controller

[AVP]

after a little more time playing around i noticed that when car is warm and idle is fully controlled by ignition timing (IAC ref table 71C = 0) as i said before the EGTs are higher than what i would like them to be.

even after a short drive, the car goes to neutral or stops and EGTs are all the way up to 580C to 600C when really they should be around 100 degrees less. On motronic i would only see for a short time 550 max after a long drive,so i think i should dig into the IAC controlled idle more although ignition based idle seems easy and steady.

I have noticed that the more i use the IAC on warm engine, the more tuning it needs BUT the lower the EGTs fall.

Finally, since motronic always has about 8deg of TB open when the accel pedal is not pressed, i thought of trying something else. If i increase the amount the IAC is contributing to idle through the ref table, and give a bit of TB angle into it, the idle seems to rise a bit.AND EGTs fall.

there is a pattern there and i will look into it more...

[rob@vems.co.uk]

Make sure that the TPS is right for the VEMS, while its a good idea to compare the two systems, they will have different readings and different features.