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-   -   Sick of high idle, please look at my idle settings (https://www.miataturbo.net/megasquirt-18/sick-high-idle-please-look-my-idle-settings-56148/)

thirdgen 03-09-2011 01:25 PM

Sick of high idle, please look at my idle settings
 
1 Attachment(s)
My car idles between 12-1400 RPM and I'm tired of it. Here is my current idle table. How do I get the idle to be closer to stock? Do I adjust the values in this table?
Attachment 19912

miatauser884 03-09-2011 01:52 PM

I've found that while my car is warming up below 130 degrees, it likes a lot of WUE. Like 12.0 AFR. The car definitely lets you know when it is happy at idle.

y8s 03-09-2011 02:01 PM

does the ecu do closed loop idle?

Braineack 03-09-2011 02:06 PM

It looks like he's electing not to...reasons unknown.

thirdgen 03-10-2011 01:10 AM

1 Attachment(s)
Attachment 19918
My .msq was always like this in idle settings ever since I went MS2. How do I get it to run closed loop? If I do run closed loop, will I ever see idle under 1000 RPM?

richyvrlimited 03-10-2011 03:19 AM

That dropdown box, change it to PWM Closed loop....

Yes you can, but prepare to get frustrated qucikly and often whilst you tune the idle.

miatauser884 03-10-2011 08:11 AM

Be prepared to read the MS3 closed loop idle tuning doc. Print it out and plan on 30min of idle tuning. Just do it. Don't try to tune a little here and a little there. It all works together. The msextra doc also gives a brief description of what each parameter does.

thirdgen 03-10-2011 08:57 AM

I'm here right now: http://www.msextra.com/doc/ms3/Idle_Control.html
thanks for the info!

Braineack 03-10-2011 09:00 AM

yep. takes penitence and a lot of rereading to get it good.


if anything, to lower your idle speed, you'd just need to lower to PWM DC% numbers in the table you posted.

the lower the duty cycle, the lower the idle speed. Just think of it as the amount the valve is cracked open. 0 = closed 100 = open.

if you lower the numbers and the idle speed doesn't decrease, you need to turn the screw on the TB and let less air around the butterfly.

hornetball 03-10-2011 11:18 AM


Originally Posted by Braineack (Post 699712)
yep. takes penitence and a lot of rereading to get it good.


if anything, to lower your idle speed, you'd just need to lower to PWM DC% numbers in the table you posted.

the lower the duty cycle, the lower the idle speed. Just think of it as the amount the valve is cracked open. 0 = closed 100 = open.

if you lower the numbers and the idle speed doesn't decrease, you need to turn the screw on the TB and let less air around the butterfly.

I wasn't sure there was an idle screw on the '99 TB, but since there is, keep the following in mind . . . there are three things that determine your idle speed:

1. Idle Air Control Valve Duty Cycle (already mentioned)
2. Idle Screw (already mentioned)
3. Spark advance in the idle region

That's it.

thirdgen 03-10-2011 11:58 AM

I always looked at it like this...If the car idled fine with the stock ECU, then why would I even think about moving the idle screw? It's all ECU related. Like mentioned above, 1 and 3.

hornetball 03-10-2011 12:01 PM

Ooops. One other thing . . . :

4. Vacuum leaks

Are your sure everything is tight?

Braineack 03-10-2011 12:42 PM


Originally Posted by thirdgen (Post 699759)
I always looked at it like this...If the car idled fine with the stock ECU, then why would I even think about moving the idle screw? It's all ECU related. Like mentioned above, 1 and 3.

so what happens if you reduce the idle valve's duty cycle?

thirdgen 03-10-2011 12:43 PM

No vacuum leaks for me. I've been there and know what that's about. It happened when I swapped in my 460's the first time, it's pulling at least 21 inHG at idle now.

thirdgen 03-10-2011 09:18 PM

I'm at work right now and I just thought of this. What if I warmed my car up and unplugged my idle valve wire? What if the idle doesn't change?

richyvrlimited 03-11-2011 03:38 AM


Originally Posted by thirdgen (Post 699972)
I'm at work right now and I just thought of this. What if I warmed my car up and unplugged my idle valve wire? What if the idle doesn't change?

1) Idle valve is fubar.
2) Idle output from MS is fubar.
3) Wiring between idle valve and MS is fuber.

Reverant 03-11-2011 04:40 AM

If you have a high idle, unplug your valve and the idle doesn't go any lower, then either the idle valve is faulty or you do in fact have a leak.

Braineack 03-11-2011 08:06 AM

What if, and I know this is a big if, you go hook up your laptop and adjust your idle settings?!

muythaibxr 03-11-2011 10:29 AM

If you can't control the idle speed with warmup only, switching to closed loop will do no good.

Make it so you can make the idle speed go up and down using the warmup-only table before moving any further.

Additionally, once you can do that, make sure you can drive around and have the idle return to a stable RPM without oscillation as well.

Ken

bearda 03-11-2011 10:34 AM


Originally Posted by Braineack (Post 700079)
What if, and I know this is a big if, you go hook up your laptop and adjust your idle settings?!

+1.

Play around with the idle valve test mode and get a feel for how it reacts to different pulse widths. Take a data log of a warmup from completely cold to when the thermostat opens, just idling without moving. That should give you a feel for what coolant temps cause you to idle high, and where you can pull down the pulse width values on your warmup curve.

Not all idle valves are the same. Figure out what yours likes.


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