Modifying Motronic 2.3.2 ECU hardware and software.

[curamrdan]

With Vems, MAxxECU you can download free software and maps are widely available.

Im asking concrete on factory ecu to confirm my findings or find what i assuming wrong.
No basics how boost tables may look like in general.

[filip.krticka]

Can somebody show correct shaped request boost + wgdc boost maps ? Doesnt matter which software.
I dont know WGDC value conversion, just comparing boost and wgdc maps side to side -> more dc = more boost.
The AA softare make sense, but RS2 no. C software have reguested boost(16x10 table) last 5 rows same boost(just first left - highest? rpm collumn is different) but wgdc has same only last 2 rows, and last collum with dropped boost is not dropped in wgdc. B software has same wgdc table as C, but request is different.
Maybe axis are not same?

With Vems, MAxxECU you can download free software and maps are widely available.

[curamrdan]

Can somebody show correct shaped request boost + wgdc boost maps ? Doesnt matter which software.
I dont know WGDC value conversion, just comparing boost and wgdc maps side to side -> more dc = more boost.
The AA softare make sense, but RS2 no. C software have reguested boost(16x10 table) last 5 rows same boost(just first left - highest? rpm collumn is different) but wgdc has same only last 2 rows, and last collum with dropped boost is not dropped in wgdc. B software has same wgdc table as C, but request is different.
Maybe axis are not same?

[blackS2]

Dwell table values are based on the engine/crank angle. Higher rpm needs more degrees to achieve the same dwell time.

[curamrdan]

Intresting. Thanks guys.

[kymi]

Dwell table values are based on the engine/crank angle. Higher rpm needs more degrees to achieve the same dwell time.

[blackS2]

I will try to ask. Can anyone help me with conversion dwell table to msec and correct shape of it?

So far i have this , raw values with correct axis. It doesnt make me a sense if higher value means lower dwell , then its not correct to have smaller dwell at lower voltage.
If higher values mean higher dwell, then doesnt feel correct to have higher dwell with higher rpm. These are my toughts if i compare some dwell tables of other newer or older motronics.

Thanks.

This map is more complex than ignition or fuel maps. Its not simply converted by a constant. I could post the entire formula but it spent to much time on my own to solve this. It uses also rpm to convert the values, so you get different dwell times for the map value 157 at different rpm for example.

[curamrdan]

I will try to ask. Can anyone help me with conversion dwell table to msec and correct shape of it?

So far i have this , raw values with correct axis. It doesnt make me a sense if higher value means lower dwell , then its not correct to have smaller dwell at lower voltage.
If higher values mean higher dwell, then doesnt feel correct to have higher dwell with higher rpm. These are my toughts if i compare some dwell tables of other newer or older motronics.

Thanks.

[kymi]

Should there be any updates? If you need updates on this thread just ask if you have something on your mind.

[1gcrazy]

Just wanted to revive this. I was following along when VWNut was doing this a while ago. Looking to catch up but see there hasn't been much activity. Are there any updates?
I'm a bit more advanced in my ECU knowledge than before so hoping to understand a bit more this time around.

[vincentroyc]

There should be no problem understanding the 3d interpolation if you know 2d interpolation. When you look at the "read_3d_map_rpm" function, "read_map_value" interpolates every read and then those two map values will be interpolated. Things are stored in temporary ram_4x locations. Interpolate function returns the same accumulator it always does. No knowledge, no motronic, just pure code and math.

Ok so the main fucntion the reads 3D maps by passing in the map lookup table address to find the right map alsways return the final value via the A register? So after every lcall of this function A should be the final value interpolated right?

Also, i think that RAM_67 may be Raw ECT value and RAM_68 the IAT?

How are the knock sensor read. ViA ADC? Or is it a interrupt generated multiple time depending on knock intensivity?

Thanks

[kymi]

There should be no problem understanding the 3d interpolation if you know 2d interpolation. When you look at the "read_3d_map_rpm" function, "read_map_value" interpolates every read and then those two map values will be interpolated. Things are stored in temporary ram_4x locations. Interpolate function returns the same accumulator it always does. No knowledge, no motronic, just pure code and math.

[vincentroyc]

Now this sounds better. Keep on going!

Talking is cheap and it always helps. My wife just ignores my disassembly chat at home, but still talking to that "wall" has helped me a lot.

But one thing I can't seem to get to is how does the value is used at then end when interpolating in the maps I just don't understand where the values are put at the end to be used A lot of 3D maps are read by the same routine but I don't figure how the same routine knows where to put or how to return the final value. Any hint on that or general basic motronic knwoledge?

Also, I was thinking about it and knock sensor are not a sensor that has a vule maintained its more of an event, so i would have probably think it generates an interrupt, but are the values readable via ADC too?

thanks

[kymi]

Now this sounds better. Keep on going!

Talking is cheap and it always helps. My wife just ignores my disassembly chat at home, but still talking to that "wall" has helped me a lot.

[vincentroyc]

Sorry about this silence, I've tried to gather some ideas for this reply. First of all, you're working with non-rs2 boost binary. Most of us here use rs2 boost binary by nature or by prj's recommendation. This means that we have different map locations, sizes and function start addresses don't match.

Have you checked this post by prj? It will not be 1:1 with your binary, but you get the rough idea of the function address structure. If I had to guess, your 0x68C is knock detection and 0xE0C is boost control. Don't treat this as a fact, I'm just guessing (but I feel lucky). This will help you dramatically to link adc inputs, tables and real life variables.

RAM_6A is not the map sensor.

Bit hard to comment on the maps, as the addresses and sizes differ. I don't want to write assumptions of those. There seems to be a few points out of my low-priority todo list also, but I got to get my car runinng before I can confirm those...

Thanks for your reply, I was half on the right way. Sometime talking with someone helps because i think now i found the map sensor. I discovered the max boost check function and map that is 0x29f6 and the function cpl A and add the MAP value which
is held in 0x6D and uses the C bit to do some check if i am not wrong, is it?

Yes sorry, I am using the 551AA since my car is a 93 URS4. Important to mention.