Hello mah dudes, trying to staying sane during all this shit that is going on right now I decided to revisit a project that I always wanted to see running: True VAG ME7.5 speed density. The simplest way for this, is to read the pressure into the intake manifold and write it to ps_w.

First thing: Yeah, I have a MAP in the intake.

The shitbox I am working on is a 2001 S3 8L with a HKS2835 (GT3071R with a T2 housing) and I am using the 8N0906018AH/360322 software.

I will be using the rear 02 sensor for interfacing with the MAP.

I will post all the development I did so far for you guys to criticize, none of this software had been tested on a running engine, but everything works fine on the bench. Attached to this post are the modified bin and a damos for this software version.

So, we need to read the voltage from the ADC pin, filter this shit, converter it to a pressure value and write it to ps_w.

Luckily, Bosch already did most part of the hard work for us in the code of GGDSAS, so I will just copy and paste some shit that I know that works and modify it a little bit. The function located @8A1C00 converts and filters the signal. The original Bosch function is @8618F8. Call @861A44.

The function @8A1B70 initialize the values when the ECU is started. Call @861874.

For reading the ADC, the function located @8A1A94 is used. Call @822A68.

The function @8A1B00 is needed to zero the accumulator. Call @822920.

For copying the values to ps_w, I modified the bgsrm-bps function in the original code. We also need to calculate dpsfg_w if we want to keep BGRLP enabled. I also modified the call to bgsrm-bps (located @822920) to land at the right place.

I am currently waiting for some parts to make my shitbox run again, as soon as they arrive, I will test this file on the car.

If someone want to port it to the 2.7t bin to speed up the development, I will gladly help. However, I will not spoon-feed you.

Why are you so triggered with the mafless word? 

Fuckin' mint!

I wrote this code a long time ago and never figured out how to make it sample cranck sync. Today I realized that it was simples than ever: ps_w calculation is already running in the sync raster, so if I sample the ADC at this point, its done.

Is it simple as that or am I overlooking something?

Forget to mention: The conversion time is under 5μs, so we shouldn't have problems waiting for the ADC with that jnb instruction, but if necessary, I (think I) have solution for this.

For filtering, I think a simple lowpass filter will be enough. I mean, its good for the MS6, so...

Couple of cents from me. First, can't you really find a spare ADC input on your ECU? On my ME7.9.10 I found and tested one spare linear ADC 0-5V channel connected to the "outside", and two with bias resistors for temperature sensors (yes, I know these are pretty much useless for MAP).

Pulsations  - I never actually studied how my factory speed-density ECU samples the MAP sensor, not too difficult to look it up though. And in all other ECUs I worked with I did not pay attention either, just assumed it's done right, but... on my previous car the MAP sensor was mounted external to the manifold and had a physical dumper on the vacuum / boost connection line. I experimented with removing that dumper a couple of times, and there were clearly differences in the signal that the ECU was receiving. So perhaps, just perhaps, there could be a physical solution in your case?

There is probably a spare port on the ECU, but there is no difference in doing this, only extra work.


Can you post the disassembly of the ADC been read and the filtering process?

Can you post your bin? Do you have a DAMOS/A2L for it? 

Why dumb if the original loom reach the sensor and have the same pin as the new connector? Just need to repin a single wire in the ECU connector for supplying 5V and its all good to go.