MoTeC Global Forum

Hi
On my Ford small block v8 controlled by an m84 ECU I have an Edelbrock 3878 Throttle Body which comes with a "Hitachi Linear IAC Motor (Pulse Width Modulated)" idle control valve. I have the engine running fairly well but skipped configuring the idle control valve built into the throttle body since I couldn't figure out where to find the configuration parameters. Is such a valve a fairly standard control valve for that you'd have settings for? I have no other info about the part number of the control valve unfortunately. It has two input leads - +12V and a PWM input.

Thanks,
Kurt DelBene

Provide 12V power to the IAC valve and connect the PWM input to an M84 AUX OUT, then configure the M84 - Adjust->Auxilary Output Functions for PWM Idle Control -- set up parameters as required (start with 200 hz, Output Mode = 0), then use Adjust->Functions->Idle Control to tune the PID after setting up the Idle Aim RPM.

Hi Daviid. Thanks for your reply. I'm not sure I'm tracking your suggestion. If I configure the Aux output to be PWM Idle Control, then here are the parameters I am supposed to set:

Proportional Gain
Integral Gain
Derivative Gain
Dead-band
Activate TP
Activate Ground Speed
Activate RPM
RPM Filter
Air Con Increase
Power Steering Increase

There's no help available when I hit F1, and I have no documentation on the Hitachi idle control valve. I was looking for some help on setting these parameters, at least as a starting point.

Thanks!
Kurt

I don't have the answers for your particular vehicle, but I can tell you how to do the work. See these webinars on PID tuning:

PID Parameters Explained: http://www.youtube.com/watch?v=16Clfh5eBzg&hd=1

Tuning PID: http://www.youtube.com/watch?v=SefKQb9y_B4&hd=1

Helpful Hints on Idle Control: http://www.youtube.com/watch?v=H-zHSvZ7PSg&hd=1

To Tune the PID, with the engine at normal operating temp you set the Target IDLE RPM, then start by setting the Proportional, Integral and Derivative gain to zero, Setup the Adjust->Idle Control-> Normal Position Table to initially have an axis for Target Idle RPM (later you will want to add engine Temp). Now you can change the Target Idle RPM and tune the Normal Position Table to the values that will achieve that idle. With this baseline (open-loop) setup. Then change the target RPM and see how the system responds.

You can then add a small amount of integral gain, and play with proportional gain to allow you to set any idle RPM you want and achieve it quickly. You iterate on this to make sure you can support the full range of target idle RPMs you might wish to use.

There is a small amount of help shown for each parameter on the Setup screen, and the other tables (such as AIM RPM - start with that one) have additional help with F1.

David has done a good job of describing the process needed to get the idle control working, so I will not add to that.

As far as having some base numbers for this sort of setup, the issue with providing this information (the same as with Cam Control setups) is that two seemingly identical engines may require quite different numbers, and starting with the incorrect values can actually take longer to get working compared to following the process laid out by David above.