Ford Idle control valve and Motec

[andygtt]

Hi all.

I have recently put a Motec M800 on my noble... works great except at idle.

Noble removed the ford idle control valve and decided to control idle/ anti stall using the ignition in the ECU... due to the soft stock ST220 cams and heavy flywheel this was ok and was able to work.... Unfortunatelly I have fitted some slightly wilder cams and have lightened the flywheel/clutch by 10kgs... hence its lumpy around idle and stalls easily.

So I want to fit the ford idle control valve back in, its back on the car, I have 2 wires to it which both go into the ECU. the valve takes a positive and a negative that opens it.

Off the car the idle valve is open as a default with no wires to it... however when on the car with it running it is clearly shut by the vacume and the car idles ok, put a positive and negative to the valve while running and it opens and the car revs due the valve opening.


So onto the bit I need help or advice.... I now need to control this within the ECU, anyone have any advice as to were and how I may going about getting examples of how to manage it, I have set the ECU to run the idle control table and using the negative (so positive is always on negative switches or pulses).

Do people just play with these things, or is there a chart or setup somewere with examples etc.... I kinda don't know were to start?

I know many will think I am mad wanting to do these things myself, but I didnt know how to make vac bagged carbon till I tought myself to do it this year... and Im a software consultant by trade so the software itself doesnt scare me.. I just need to know were to start lol

Any advice gratefully received

[SuperchargedVR6]

I would start off just using the PWM table to begin with and see what kind of percentages give the kind of idle speed you want. Then you can start playing with PID to get the closed loop idling to work.

From memory, I used a zetec valve on my 3.0 motor and it needed around 40% PWM to hold a 900rpm hot idle. IIRC, I used a control frequency of 200hz, but if you can find any manufacturer specific info on it, I would use it!

In a nutshell, open loop idle will just open the valve a set amount. This usually results in an idle which is too fast in winter and too slow over summer, and also too slow when the motor is heat soaked (i.e. coming back to it after paying for fuel).

Closed loop will always (try to) maintain the desired idle speed and works so much better in a road car, once you get it setup. Getting it there can be a long and tedious road unfortunately, which as you say, will just be a lot of experimenting on your part.

Try and add a bit of fuel and timing to the cells below the idle speed. This can help with engines that stall easily by bumping the revs back up again if they drop below the target. I also like to open the valve way above idle speed too, just to ensure there's enough air when you come out of over-run.

That's about it really.... good luck!

[stevesingo]

This is a data sheet from Mtec for the M4/8 ECUs but has good info for wiring, frequency and min/max duty.

http://www.motec.com/filedownload.php/v13.pdf?doci...

I will look on my Motec ECU manager when I get home from work for a better idea of the full set up.

If you shoot me an email, I can look at your cal file and edit a copy with some baseline stuff.

I also habe a motec document on PID tuing which is a good read.

Steve

[stevieturbo]

The dedicated idle function on the M800 is closed loop PID's only

I hate PID's lol

But in essence, you need to set a decent base idle with no valve open first, ( ie set your base idle using the throttle ) and for the most part the idle valve is used to lift the idle speed when cold and to help stabilise. Whether it can compensate enough, or react fast enough to give you a smooth idle with the light flywheel etc is another matter.
Ford valve will want around 300Hz from what Ive read

With regards to the PID's, really it is a case of trial and error.

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

[andygtt]

Thank you all so much this is exactly the info I was hoping for

I estimated the control frequency of 180, I used aux1 as the 12power and aux 2 for controlled negative set to 2 PWM idle control and set to high polarity.

so it seems I was on the right track... will reset to 160hz frequency and then play with the table as at the moment its blank lol


currently the throttle body is set to leave the butterfly open a smidge to control idle... hopefully I can do it better

[Thom]

You should be able to adjust your PID settings so that the adjusting screw on the TB is made redundant (=fully screwed in).

Edited by Thom on Friday 23 November 13:21

[stevieturbo]

andygtt said:

Thank you all so much this is exactly the info I was hoping for

I estimated the control frequency of 180, I used aux1 as the 12power and aux 2 for controlled negative set to 2 PWM idle control and set to high polarity.

so it seems I was on the right track... will reset to 160hz frequency and then play with the table as at the moment its blank lol


currently the throttle body is set to leave the butterfly open a smidge to control idle... hopefully I can do it better

Any such valve will receive an ignition based 12v, then any -ve controls from the ecu. Only one output is needed for a basic valve.

Throttle opening should always dictate the base idle speed anyway. Hook up the valve, set it's output duty to zero ( or target idle speed well below your desired target ), then adjust the blade to give you your base idle, or slightly lower.
Then reset the parameters or target idle speed, and raise the duty to achieve your desired idle speed.