MoTeC Global Forum

Hello!
I'm using Motec M800 ECU in my STI'07.
Please, help me to calibrate idle controlling function.
The main problem is:
- when heat fan activates, RPM falls down to 100-200, and idle compensation works too slow.

Secondary problem is:
- how to control lowest RPM on the way. For example, - driving car aprox 100kmh, press clutch. In this moment, RPM falls to 100-200.....and only then, motec gains TP.

My idle setup:


Aim RPM = 1000
Aim RPM Comp = 0
Min Output = 3
Max Output = 12

I have a 302W and i found that i had to set the normal position first with all PID settings at 0, then set the lowest for P to get the engine to "hunt". from there i stabilised the idle by increasing D to smooth out the "hunting". Then I was introduced to allow for cold running/start and power steering etc

My Settings:

Proportional 0.16
Intergral 0.150
Derivative 0.35
Dead band 30 rpm
Activate TP 3.0
Ground Speed 4.0
Activate RPM 1400

Try this pdf, it's a Motec item i found a few years ago.

Great thanks ! Will correct PID of idle today.
And what to do with idle on-the-run ? My secondary problem ?
As I understand, it is Overrun Fuel Cut function?

The on-the-run idle should also be fixed with a correct normal position because when the engine rpm drops below the activate rpm, the ecu will open the idle valve to the normal position, which will supply the engine with close to the required air to idle. This initial air supply dramatically slows the rapid drop in engine rpm giving the ecu time to react.

You might want the activate rpm higher than what i have, because for me, it is that low to smooth the transition from overrun fuel cut to idle during engine braking.

If it is a DBW car the "on the run" idle should be controlled by the translation table, not the idle control. You have an activation speed of 15km/hr which is basically fine.

You do not have very much Proportional gain so if it take ages to pick up the idle after the fan goes on it is probably just relying on Integral gain mostly.

The idle control is a system which includes the fuel and ignition as well so there is a lot to get right. Don't just copy PID settings from another engine (although the offer is appreciated) as the system is different.

Great thanks, Mark!
I corrected my idle configuration, it is almost fine.
To control fan functions I've used normal position compensation. X axis = ET, Y axis = Inj 6 (fan) 0/100.

I would expect a Subi to have vastly different settings with idle due to the engine power output at idle. My V8 only drops by ~80 rpm when i hard lock the steering and it has no sense for A/C, P/S or any other load fluctuations. I have found that with the normal setting set and no idle compensations, i can drive off without throttle on flat ground and change into 2nd(manual-still no throttle). Only cold start gives me problems with idle. I need the idle at 1200rpm to start and run on a dewy morning.