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-   -   Life without ISC. What's it like? (https://www.miataturbo.net/general-miata-chat-9/life-without-isc-whats-like-54002/)

Reverant 12-02-2010 11:59 AM

You're doing it wrong.

Braineack 12-02-2010 12:00 PM

What he said

How long is your crank to run timer? Is your cranking idle PWM table too high?

miatauser884 12-02-2010 12:13 PM


Originally Posted by Braineack (Post 664257)
What he said

How long is your crank to run timer? Is your cranking idle PWM table too high?

Here are my settings

Should I have selected IAC closed loop instead of PWM closed loop?

https://www.miataturbo.net/picture.p...pictureid=1393

Braineack 12-02-2010 12:59 PM

Post the CL idle valve settings and CL idle PID settings.

The coolant based cranking table is what PWM% your idle with will be positioned while you crank and where it will sit before the PID closed loop kicks in. If your idle is shooting up too high after intial start, you should lower those values. Also double check your RPM targets aren't too high.

miatauser884 12-02-2010 01:05 PM

https://www.miataturbo.net/picture.p...pictureid=1394

I just changed my "crank to run taper" from 5s to 2s. I have not tested this yet.

Reverant 12-02-2010 01:17 PM

Increase crank to run taper to 4 or 5s.
Same for PID ramp to target time
Increase PID lockout rpmDOT - try 100.
Increase PID disable RPMdot to at least 500
Your dashpot adder is high, try 1% or none at all.

jbrown7815 12-02-2010 01:19 PM


Originally Posted by Braineack (Post 663846)
When I left my Internet Scrabble Club I regretted it. I felt alone and impudent. They refused to let me rejoin.

:bowrofl::bowrofl::bowrofl:

Faeflora 12-02-2010 01:23 PM


Originally Posted by Braineack (Post 664215)
why?! have a thing for sweaty balls?

Damn you megasquirt freaks GTFO with your jibjab and all

I want a low mount ramhorn vband artech manifold.

miatauser884 12-02-2010 01:27 PM


Originally Posted by Reverant (Post 664281)
Increase crank to run taper to 4 or 5s.
Same for PID ramp to target time
Increase PID lockout rpmDOT - try 100.
Increase PID disable RPMdot to at least 500
Your dashpot adder is high, try 1% or none at all.

OK, I made those changes, and will test at lunch. I'll reduce the coolant crank duty% if this doesn't work. My target RPM when cold is 1100rpm.

Braineack 12-02-2010 01:41 PM

yeah if you look at your settings the max the MS ever try to allow your valve to go is 40% when in PID mode, so you initial cranking duty table looks like it would cause high RPMs.

The rest dimitris suggested to change probably have little effect, just the delay before the PID code kicks in. I use 3% dashpot adder, I like the idle to drop 100-200RPM above my target and settle in.

For RPMdot lockout, just turn the RPMdot gauge on, watch it at idle and change the value to be 10 points above it. I see 80 on my gauge, so I use 90.

miatauser884 12-02-2010 03:03 PM

So far so good on my drive at lunch. I started the car and immediately started driving. The idle settled fine. I'll have a better idea tomorrow when it is colder, but the car had been off for 5 hours so it normally would have hung the idle open.

I used to have the idle valve set to 98% After datalogging I saw that my IAC never opened past 41% or closed below 21%, so these are the values that i set for max and min. I guess increasing the max to 100 won't hurt anything.

Braineack 12-02-2010 03:15 PM

well. go to idle valve test mode and find the range in which it acutally works. You don't have to plug in the actual numbers, reducing the window like that will increase your resolution/sensitivity. When it's cold or going uphill in first gear you might find you need more than 40%. I think I have mine set to 60% but it doesn't go open any further after that point so that's the full open point.

miatauser884 12-02-2010 04:18 PM


Originally Posted by Braineack (Post 664344)
well. go to idle valve test mode and find the range in which it acutally works. You don't have to plug in the actual numbers, reducing the window like that will increase your resolution/sensitivity. When it's cold or going uphill in first gear you might find you need more than 40%. I think I have mine set to 60% but it doesn't go open any further after that point so that's the full open point.

Ok I set the step size to 100 int he idle valve test window. I'll check it out before I leave work tonight. I've never used this before. Will it run through the check with the ignition on since the IAC valve is on, or does the car need to be running?

Braineack 12-02-2010 04:21 PM

yes, run the car. go to idle valve test mode, and plug in the number you want to sit the valve at. if you put in 0, the valve will be fully closed. Increase it until your idle speed acutally rises. Then you know this is the lowest dc% number that acutally works the valve. Keep going up until you find the highest value that increases the engine speed. Then you know what the max dc% is.

You'll have to restart the car in order to go back to normal idle.

miatauser884 12-02-2010 04:52 PM

What base settings do I select "home" or "run"? Do I set both to zero initially?

https://www.miataturbo.net/picture.p...pictureid=1395

Braineack 12-02-2010 05:23 PM

once you turn it on, change Move to home or vise versa. then you change the iac step value 0-100%.

miatauser884 12-02-2010 05:29 PM


Originally Posted by Braineack (Post 664412)
once you turn it on, change Move to home or vise versa. then you change the iac step value 0-100%.

What do you set "iac home steps" to? 0 or leave it at default 160?

Braineack 12-02-2010 06:32 PM

that doesnt pertain.

miatauser884 12-02-2010 09:49 PM

your t, once plugged in it became obvious. I started at zero. My idle was higher than normal. As I increased from zero the idle dropped to normal. Then when i got to 17 it started to increase. It increased all the way to 98, but stopped dramatically increasing after 82. I set my min value as 17 and my max value as 82.

shuiend 12-02-2010 11:07 PM

That is where my IAC is remotely located. It is on the drivers side right next to the headlight. The lines are a bitch to run to it.
http://www.boostedmiata.com/gallery2...202_152413.jpg


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