Modifying Motronic 2.3.2 ECU hardware and software.

[vwnut8392]

im still trying and finding the rev limter on this thing with no luck. i read that the automatic AAN rev limiter is 6600, the manual AAN rev limiter is 7211 and the RS2 rev limiter is 7196. strange that the RS2 is lower than the manual AAN. anyhow, i used used the motronic.ws site where they suggest that if i take a what the rev limiter hex value is and divide it by 983600 it will show the real rev limiter value. EX 983600/hex=rev limit. seems simple enough so when i discovered actual values above i figured id work backwards by going with 983600/7211=136. now 136 is decimal which needs converted to hex and the hex value of 136 is 88. so i have searched high and low comparing the 551C manual file and the 551D automatic file hoping that 88 hex will jump out with absolutely 0 luck. am i doing this completely wrong? does the motronic.ws site have false information on it?

i have even tried to use what the motronic.ws site suggested to figure out the type 3 rev limiter and it give me nothing. i've been staring at this for almost a year now and cannot figure it out.

[bolec]

can anyone help my to calculate checksum?

https://www.sendspace.com/file/rdcezd

[prj]

It will work yes ... no reason to do it though, use RS2 base.

[-ice-]

Ok, i have seen the checksum routines. One checks from 0x3fff downwards and the other from 0x1fff downwards. The algrorithm is a bit confusing, it checks 0x00ff to 0x0000 first and then 0x3fff to 0x0100

Also discovered a RAM test, which tests every cell at startup. Very cute..

So if i have a 8kb Rom and copy this into 32kb eprom it will work? Im asking because I have a never used stage1 tuning chip with 8kb boost chip an i'm curious to try it out at least once (with my newer motronic of course...)

I guess the old motronics dont have A13 and A14 wired on the board.

Regards and thx for your help

[prj]

The software is exactly the same until RS2 came around.
With small modifications the newer software will run in the 8k chip (checksum range etc) and will work on the older ECU.

That said, the 551A should be avoided due to the extremely rare 87c64 chip.

[-ice-]

Hi,

Just a question concerning the "old" Motronics with 8k boost eprom (f.e. 551A). Is there ayny hardware difference on the circuit board in comparison to the newer versions?

Im thinking for example at fewer adress lines (i will check this with the eprom datasheets...)

Just looked at the boost board a little bit. It also seems to have a small x-ram on the bottom side.

Regards

[prj]

Good evening,

Interesting to see that the MAF voltage is converted to a frequency (by a discrete VCO Chip on the boost Board). This frequency is fed directly into the IGN processor and counted with a Timer.
So with more airflow the counter register is incremented more often. Not clear at moment is how this counter value is snychronized with the rest because its only read by an external interrupt serice routine. The question is, how long (or how many periods) does the timer count until it is reset?!
That are questions i study at the moment

Regards

IEX3 / IEX0

[-ice-]

Good evening,

Interesting to see that the MAF voltage is converted to a frequency (by a discrete VCO Chip on the boost Board). This frequency is fed directly into the IGN processor and counted with a Timer.
So with more airflow the counter register is incremented more often. Not clear at moment is how this counter value is snychronized with the rest because its only read by an external interrupt serice routine. The question is, how long (or how many periods) does the timer count until it is reset?!
That are questions i study at the moment

Regards

[prj]

Ok the map i'm looking at has it's maximum (high threshold) at 3000rpm. So setting the value to 0 should disable the lambda control.

This is correct.

Try it with standard maps and wideband. You will understand in some seconds.

There is nothing to try, he knows exactly how it works. And it works exactly the same on your ECU if you are editing the right map.
The only difference on your ECU is that fuel trim will remain active in entire range, even when open loop, and on his it won't, so on your ECU you need to also clear codes to reset learned fuel trims to 0.

No need for BS.

[Acki]

Try it with standard maps and wideband. You will understand in some seconds.

[-ice-]

My thought was, that every load value is greater 0, which disables lambda control.

But i haven't looked at the binary yet...

[Acki]

0 does not make the change you want.

[-ice-]

Ok the map i'm looking at has it's maximum (high threshold) at 3000rpm. So setting the value to 0 should disable the lambda control.

[prj]

Unneccessary questions. Read ME7 FR to understand "Dauerklopfen", and compare these two maps in binary.

[Acki]

At my v8 I have this map.
How do you mean for longer knocking (dauerklopfen) events? The enrichment? Lambda deactivation during knocking?