Electronic Stepper Control is actually quite easy ... Idle Control (which is what this thread is really about) is actually quite hard.
I'm grateful this thread is talking about this ... its giving me inspiration enough to probably pull the Hitachi SH2 spec on the EVO's computer and see what means there are for a full out OS replacement.
~j.

 

Its so nice to have the armchair commentators chime in. Have you even looked at the idle stepper control subroutines?

Idle control is idle stepper control based on the target idle value (and everything else that Mitsubishi has in the stepper control subroutines). The target idle routines are relatively simple with very normal target idle values under all conditions. The problem is that the stepper value shoots to the moon under certain conditions despite a normal target idle value and doesn't come back down.

 

Ahh Fred ... always so bright and cheery ... here's a

I've been close on the idle stepper control subroutines. I was hoping to spend some additional downtime for the last couple months digging into the EVO computer, but then I went from 0 hours on ironically a SH3 small satellite processor to 12 hours. I could tip my hand towards not seeming like an armchair commentator, but why throw all my cards out to an ***-u-ming and seemingly hostile crowd?

Regardless, most of the EVO control routines seem to be close to simple PID loops. I.e. target values to hold, just like you've said. I suspect something as simple as a gain value getting out of control (in PID loop), or it could be something as simple as a corrupt digital value getting popped in there.

You know, this is an amateur based forum. Did you expect a few 'armchair commentators' to not chime in?

Cheers!

~j.

 

I don't mean to come across as hostile, but its annoying to have someone come out of nowhere and make some off-the-cuff statement about idle stepper control being "easy", especially when they offer nothing substantial to explain their statement. Since you have been working on the idle stepper control subroutines and truly think they are easy, then you are the man because I know that if that stuff were "easy" for me, I'd have most of the entire engine control program disassembled by now. So, do you plan to share your idle stepper control disassembly results? Will you be done soon? I'd like to know because I don't want to waste my time disassembling this stuff if someone else is already doing it and is going to share the results.

 

Mr Fred, do you have the error maps for the idle control? I found them a while ago, and they trim the number of steps based on how far rpm is from target on what must be a timer (didn't look for it).

The system is similar in a way to the O2 closed loop system. The idle control remembers a trim amount. You can notice this if you have done a hard reset and all trims are zero. The car may idle low and over a few minutes it will slowly pickup and stabilise as it learns the trim offsets. One day I will have to track down if the trims can be viewed somewhere in the MUT table, but who has time these days :-)

Related to the Idle Control routines, What does MUT 1E log? It shows up in alot of subs.

 

MUT_1E is a bit array and many things are inside, this is what I could find out
--------------------------------------------
Bit position definitions (15-0, L-R)
--------------------------------------------
0: Coolant Temperature in range
1: Manifold Absolute Pressure in range
2: Unknown
3: Unknown
4: Is Immobilizer confirmed
5: Unknown
6: Unknown
7: Unknown
8: Unknown
9: Unknown
10: Unknown
11: Unknown
12: Unknown
13: Unknown
14: Unknown
15: Is in idle

 

Thank you, thank you, thank you ! ! !

 

any more info on this?

 

I could use some info as well... All i've learned is something about SS clutch lines and restrictors and some about a stepper table? Still confused on what is actually the real fix

 

I may have found a 1D adjustment that could be a solution to the throttle hang. Looking through one of the decel fuel cut subroutines in 88590015 I found there is a 1D RPM adjustment that is set at 4000rpm by default. I also noticed that most people say the throttle hang is above 4000rpm.

Now, the trouble is that my car does not have any throttle hang issues, so I cannot easily test this. So I am putting this up purely for interest-sake. So if someone can test it and give feedback...

<table name="Decel Fuel Cut Upper RPM Limit ???" category="Misc" address="1198" type="1D" level="2" scaling="RPMStatLimit"/>


If it does not work, then disregard it. My suggestion is to try setting it above your rpm limit so it has no effect.
If it does work however, it will be very helpful for those wanting to ge anti-lag working because you would need to have decel fuel cut disabled above a certain rpm for it to work.

 

I took a quick peak at my disassem, and this 1D item is part of the speed limit subroutine. Doesn't have anything to do with decel.

 

 

Hmmmm. OK. I saw the Speed Limit above it, but it also appears a couple of lines above the decel cut map so it looked like a good candidate.

I tested my own car today to see if there is an upper limit to the decel cut, and mine pretty much cuts at any rpm from the rev limit down, so it is not making it easy for testing.

 

Has anyone just replaced the TPS sensor out of the zillions of folks that have this issue?
I can't find anywhere in all of the posts about this where there is actually a solution. Its driving me nuts. Or revving me nuts....

M

 

I've been experiencing what I thought was this same issue of raising RPMs between shifts. When I've working through the gears quickly, I noticed that between shifts, the RPMs would still go up. Well, on the first page some guy mentioned that it was due to the fact that the clutch wasn't being engaged all the way (pressed in all the way) and that those with this issue needed to learn to drive better.... well, he was right; at least in my case. I went out tonight and had the same rising RPM issue, but then I consciously pressed the clutch all the way to the floor and viola - no more rising RPMs between shifts.... At least it was a simple fix!

Now I still have the "throttle hang" where the RPMs seem to slowly drop, but I believe this is unique to the 06-06s as an emissions thing. Doesn't bother me at all.