Joined: 20 Jun 2017
|Posted: Wed Jun 28, 2017 4:02 am Post subject: M3.3.1 motronic (413 and 506) tuning and XDF update?
|I have a bit of an odd set up with a M3.3.1 ECU running an M20B25 with the vanos disabled in the .bin (resistor replacing the solenoid to avoid fault codes) it's running and driving so I am now starting to get into the meat of the tuning.
I have been looking at the ECU and software for about 2 years now on and off while doing the conversion and car resto.
I have attempted to disassemble the binary file, I think I managed a reasonable disassembly but getting any useful info from that is currently a bit beyond me, maybe a discussion for another thread?
I have a fairly good understanding of the hardware and tuning side so I am not totally lost but there are a few things puzzling me:
1. It seems people are not adjusting the "transitional compensation" in anyway on these ECUs, standard wisdom for standalone systems is to get the VE tables right with any acceleration enrichment off and then add it after.
I understand that a lot of people are working with quite mild engine changes so maybe it is not needed for those. In my case I certainly need to work on it.
Do I minimise it in the 4x6 table so it is not messing up my part throttle tuning?
Would it be better to work with what I have, reduce the transitional fuelling to hit ~12:1 on acceleration and then tune the part throttle aiming for ~14.7-15.7 at cruise? looking at about 10:1 accelerating and 13:1 cruise at the moment on the slightly adjusted M50 map.
2. The new 506 XDF is really good, a huge thanks to evilM3666 for this.
I think from all the studying of this ECU I have done there are a few things that can be added:
- TPS voltage transfer map (32x1) - Based on the transition compensation map being 0.4 volts to 6 volts and the functional range of the TPS being .45v open and 4.5v closed, this table seems to be a map of throttle opening vs voltage.
Could the scale (Y axis) on this map be 6-0.4= 0.175 steps?
This would give the right volt values to match the throttle openings.
Charted in tunerpro it looks like this:
To me that seems to match the operation of the TPS but I am going to double check with the ADS diagnostic system VS the map trace on the ostrich.
Does that seem right?
Last edited by Hairyscreech on Wed Aug 09, 2017 3:08 am; edited 1 time in total