Hi,

In 1.9lt Diesel Car, Alfa 159, I'm adjusting the VNT maps. But before I start I need one thing if you know it. When VNT controller unit gives up controlling boost. It set "%50" to duty cycle and fu...ks up my vnt setting precedure... I know the start up value of N75 valve is = %75. Could you share me what is this VNT% of limp mode setting. I want to set it to %10 or %20 to save me. While I'm trying to set VNT on high speed. At a random time it sets to %50 and boost goes to 3.7 Bars. I don't want that...

Also I set the boost limit to high. SVBL to 3801... Now you are saying don't push 3.8 Bar in to this engine. And I'm telling you I'm not. I'm trying to set the boost to 1800mBar. But with new turbo it is not easy... to set the VNT maps in 1 minutes.. And some times it overboost about 200mBars, And I'm trying to get some datalog about desired boost + Actual Boost + Rpm + N75 duty, and after a while it sets to %50, why it is doing this. How can I cancel it while I'm trying to adjust the VNT maps?

hello,
there is more complex than just vnt maps.
You have PiD controler / positive "windows", negative "windows, maximum limits,
minimum, limits, iq dependant controls, limiters and so on. You are probably hitting upper window and PID kicks also in
than you can feel deviations on power...you need to remake complete logic of your turbo regulation and adjust it after you make
pid less conservative.

So you are saying, the map location to setting %50 VNT is on PID area of boost control. I've learned only that there are some boost and IQ areas that switches VNT maps and PID constants, Like if I'm under 1000Mbar boost & 30mg IQ, it is using Section 1, and there is a section selection maps also But before that I have to find this %50 setting area, thanks for the heads up.

well not so easy like it sounds.. the PID will not have instantanous reaction to avoid oscilation on output value, the mechanical part will be a lot slower. When you set 50%, the n75 take a bit time to move to position, the new position of vnt will produce boost, this boost will take long time (almost 1s in my case) until reach MAP sensor and tell to ecu "wow..its too much" (spike).

At high rpms you have to go slow with n75 values because will create huge spikes. IQ also affect turbo spool. It will take time and need feel the car response to adjust nicely.

https://youtu.be/vjpGcLSRPAM

Here is the first time i use boost gauge. And realize that problem.

I've found those addresses about VNT control ( PCR_Monitoring ) I think they are related about those shutoff.
Somebody said to me $1E33CC should be responsible for that shut-off value. But it is not %50 or 4096 nor near that value.

1. In its firmware MOD, include errors that are withered in the mask of the table, so that the car can write on what swears.
See PCR_pBDesATMax_MAP

I did not understand you, sorry my english has limits :roll: :cry:

You have EGR and FAP removed. And erased the error table, a few extra.

PCR_Monitor: "Pressure Charging Regulator Monitoring and Shutoff"
map 1x1 149CAA
default value 12 for relative position of boost pressure actuator
map 1x1 149CAC
default value 18 for relative position of boost pressure actuator

found in fiat chroma edc16c39 DAMOS