A4 running force motor off MAP?
03-24-2006, 01:40 PM
#1
A4 running force motor off MAP? Im running a speed density tune and wonder if with the MAF in failure what the force motor has to go off of. I wondered if I could get the force motor to run off of the MAP. I have a big cam so I would need the idle and WOT MAP pressures to know what to make the high and low torque settings for the force motor. Anybody doing this and how would you go about it. Im assuming this requires the pro version which I dont have.
Thanks!
Thanks!
03-24-2006, 04:05 PM
#2
TECH Senior Member
The PCM looks up force motor current based on calculated engine torque.
Calculated engine torque is computed from airmass which is influenced by VE table (in SD mode) and also by RPM, MAP, IAT, ECT (i.e. it is not influenced by MAF alone or MAP alone).
So as long as your VE table is good, then your calculated engine torque should be good, and so your force motor current should be good; you should be good to go.
In SD mode, the PCM derives DYNAIR from the VE table (using RPM, MAP, IAT, ECT...).
Log DYNAIR, Delivered Engine Torque, Force Motor Pressure and Current, and verify that the engine torque is tracking DYNAIR, and that the TFMPRS pressure tracks engine torque.
Calculated engine torque is computed from airmass which is influenced by VE table (in SD mode) and also by RPM, MAP, IAT, ECT (i.e. it is not influenced by MAF alone or MAP alone).
So as long as your VE table is good, then your calculated engine torque should be good, and so your force motor current should be good; you should be good to go.
In SD mode, the PCM derives DYNAIR from the VE table (using RPM, MAP, IAT, ECT...).
Log DYNAIR, Delivered Engine Torque, Force Motor Pressure and Current, and verify that the engine torque is tracking DYNAIR, and that the TFMPRS pressure tracks engine torque.