So, is ISC Steps at Request 16 like "STFT" and 08 and 0A are like "LTFT" but for ISCV demand instead of injectors? Or is ISC Steps more like IPW maybe, since it's an exact measure not a "plus or minus some amount" measurement? I guess I'm trying to think how I'll use this to set my ISCV values to get my idle ironed out. Since I am switching from a totally different engine's rom to the Tephra stuff, what I'm starting with was way way off.

Also...you'd like ISCV Demand Trims to be close to 0 I'd assume, right?

 

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So I loaded those defs into evoscan (running 9417 V7) and logged them.

The ac off trim moved from -8 to -10
The ac on trim was static at -56

So, if I read this correctly, I need to pull 8-10 ISCV steps from one of the ISCV tables, question is, which ones???

Logs attached, ac off, ac on, both with some free rev MAF induced low RPM stumbling at the end of each log, just to remind me it's still present.

 

I believe what you logged was percent though, so you don't need to pull steps, you need to pull percent if I'm not mistaken. How the heck was the ac on trim -56, if the min max ought to be +/-16?

 

The factory starting value in my ROM is -1.2%, so assuming its the same for a 9417, then -8% to -10% suggests that the ECU pulling lowering demand from the factory starting value. The -56% indicates to me that MUT 0A has been modified because the ISCV demand trim algorithm bounds the value to be -16% to +16%.

 

So the ISCV AC on and Off have changed from Load to TPS? Is that correct mrfred?

 

Not sure what you're asking.

 

I logged my iscv demand and got -7% to -11%.

Would it be easier to just close the biss down in order for the iscv to open up more and bring the trims closer to 0%? or should i tweak the tables?

Also, how can i reset the trims without unplugging the battery?

Attached is a log i just took.

 

Looks like these

Are now Throttle Percentage where before they were Load.

 

Mattjin had those tables incorrectly defined.

 

Ok thanks. I was trying to go through and make changes to my 9653 xml based off the changes you made to your posted rom.

 

Wondering which table i should be tweaking in 9653 rom. Im getting idle surge on decel. Basically clutch in and coasting down. Once below im guessing 5mph the idle stabilizes. This is definitely speed dependent. Once below 5mph (my best guess) the idle is where it should be. Moving faster than that it surges to 1500 or so then back down. As soon as im below a specific mph it drops to where it should be.

 

I've been logging ISCV trims, and it's really helped me to sort of iron it out, but only for the fully warmed up values.

I have one question that may help me iron it out at "not fully warm" levels. What is the temp axis on the idle stepper table? I know the def says "temp", but is that temp C, or F, or something else (like a different kind of temp scaling), because one of the guys I interface with regularly pointed out that 100degrees is pretty cool if it's F, but that's what my definition say sit is.

 

Units for temp on the axis of the Idle Stepper Lookup table will depend on what definition you are using. Note that Mitsu does not choose to control the temperature dependence of ISCV using this table and instead use one of the tables in my defs.

 

So I started messing with the ISCV demand readings on our 95% bone stock evo 8 to get some base numbers.

• AC and all electrical items are off
  
• Target idle is 850rpm
  
• Base ISC Step at operating temp is 7

The first thing I tried to do was set the BISS with Evoscan to 850 rpm per instructions someone posted from some service manual. Doing so would force the idle to rev up to about 1000 rpm when the actuator was disabled but there was not enough ISC adjustment to bring the idle back down but it stopped around 930 rpm(I waited until the ISC Steps in evoscan wouldn't go any lower).

So I decided to adjust the BISS without activating the actuator test in evoscan until I was reading 0% ISCV Demand. Once it reached 0%, I then activated the evoscan BISS actuator test and it reads 750rpm on the nose. I'm assuming this is actually a better BISS target than 850prm?

I also noticed that the ISCV Demand % would adjust itself every 30-60 seconds.

With ISCV Demand at 0%, my ISC Steps at idle with all electrical accessories off (including the radiator fan) reads 22 steps, just as a reference for anyone else.

I'm not sure if any of this is useful to anyone but I figured I would share.


-Jamie
(aka Jack_of_Trades)