To help me understand, what if you have different cam shafts. At 80% throttle at 4000RPM let's say the engine is breathing 15% better from the extra lift and overlap. How would the ECU compensate for this?
On an aftermarket ECU, the KPA value would be slightly higher in this scenario and I would have to add more fuel at this moment in time compared to before with the stock cams for this load/VE and RPM.
I'm not quite sure what you're asking - but if you monitored rpm, load and AFR (with a wideband) then the RPM and load values would show you which cell in the fuel table to adjust, and the WB would indicate the adjustment to be made.
Good question... and one that I don't have an answer for just yet.
I haven't really worked through much of the peripheral code yet, because without either a schematic diagram or an actual ECU to trace I have no idea what's connected to what or which external sensor/input is being addressed.
There would have to be a counter of some form, unless it used true crank angle windowing which would greatly reduce the false knock events.
I might take a look at my M1.3 ECU when I get a chance - if I can identify the knock routines in that ECU, I can probably work backwards from there to locate the M1.7's...
How did I miss that one? You're absolutely correct - it's a MAP based system.
It's also a 35 pin ECU (meaning it's most likely the same hardware generation as the ML4.1) and it has DFI... I have to get one of these ECUs to have a look at I think!
The MAP sensor is in-built, but it shouldn't be a big issue to change the code to use an external sensor.
I'll have a closer look at the wiring info in that pdf and see what I can dig up on the ECU hardware, but I'm thinking it may be possible to port the MAP and ignition code to the ML4.1 - which would let you get rid of the AFM and distributors :blink:
The diagnostic tool I have (an old Fiat Examiner) does not support the MP3.1 ECU but I have managed to connect to the ECU with the choice of a Alfa 164 ML4.1 ECU to read some sensors, rpm values (4cyl.vs 6cyl.) and AFM was crazy but the sensors I wanted to watch was OK.
I've had a quick look, and it appears that the MAP kPa might be at address 43h - which is not an address that a tester would look at for a 164.
This pic looks like a VE map to me - but ignore the actual numbers, the scaling was a rough guess so I could display the curve shape.
But here's the interesting bit - I suspect that the ECU still operates from a load based model :blink:
It appears that the VE map is used to come up with a load figure, then fuel and ignition reference the load for their map lookups.
So instead of having an AFM transfer curve, it has a VE table to do the same function.
The actual part throttle fuel tables are all set to 1:1 in the bin I'm looking at, so assume they are sort of dummy tables because the VE map by itself is enough for the fuelling.... but the fact that there's 1:1 tables in there makes me think the firmware for this ECU was made by taking an existing AFM codebase (M3.1, ML4.1 etc) and hacking MAP support into it in place of the AFM functions.
If that's the case, I should be able to find signs of this in the code.
This is exactly what I was going to do, and if I'm right in what they did and I can work out the AFM code used and isolate the changes for MAP, then an ML4.1 MAP conversion would be a piece of cake!
... but I've spent less time looking at the code than I have typing this post, so I could be way off the mark so I'll go and do some homework before getting too carried away
Unfortunately the 145's ECU uses a masked ROM like the M1.7, so I'd need to get hold of an ECU to extract the on-cpu functions before I could have a serious look at this.
I found one on ebay, but $200 is too much for me to spend on what is really only a hunch at the moment
If anyone comes across a cheap 0.261.200.695 ECU (working or not) please let me know.
I also see that there was another Alfa MP3.1 ECU - the 0.261.200.658 that was used on the 33 1.7, possibly the last of the sport wagons?
I guess that was MAP based too then, unlike the ML4.1 33 1.7s that used an AFM?
After a fairly hectic long weekend of programming, I've now ported pretty much all of 160S's extra functions to the 75/SZ 3.0 12V ('141 ECU) like simplified single map tuning, improved datalogging etc.
I'm still tidying up the xdf for it, but once that's done I'll do the same for the 164 3.0 12V ('117 ECU) and then the 33 ('142/147).
I also managed to double the speed that my Plug-in downloads data from the ECU, but was having lots of dramas with data corruption so will have to re-visit that another time and stick with the 'slow and steady' approach for now
I lost count of how many hours I wasted trying to sort that out.
I'm now thinking of maybe making my RT firmware's communications protocol a little more cooperative - not so different that it wouldn't work with an Alfa Tester or other diagnostics tools, just tweaked a bit to allow faster transfers.
This would mean my Plug-in would have to detect whether it was connected to a stock or RT firmware before switching to the faster mode, but I think that should be ok...
I've been spending a lot of time lately improving the usabillity of the RT system - making the plug-in more resilient, and tidying up the user interfaces.
Here's a couple of datalogging pics, it's slowly getting there...
still progressing faster than I can follow. I am a bit confused here: does the V6 engine of the 75 work on the Motronic ML4.1 ? I thought it was the M1.7, maybe I missed something.
Another question about the versions of the ML4.1 for the 75 TS: is there any difference in the hardware (0.261.200.108) for the 604 and 191 chip versions ? In other words, what happens if we put a 191 chip in replacement of the 604 ?