My guess is that what the ECU defines as idling is determined by TPS and whatever else. Can anyone clarify the conditions under which the ECU determines the engine is idling? I ask because I am wondering if TPS position is an aggravating factor in me getting this Hypertune TB in sync with the idle settings.

 

TPS contains potentiometer and switch. It is necessary the switch is closed at idle (throttle not pressed) and potentiometer is within values. Service manual defines adjustment of TPS – switch should be closed using 0,6mm gauge and voltage range for the TPS potentiometer circuit 0.68v to 0.72v. Idle control is also influenced by engine temperature, at cold engine there was FIAV (fast idle air valve) at least for DSM and I think it is there also for newer 4G63. And of course ISC (idle speed control valve) bypasses more air if engine is cold.
DSM idle control is described from page 156 http://xor.cz/Mitsubishi/DTM.PDF

 

I didn't realize the Mitsu TPS was a switch-type, so that tells me something I didn't know. I'll check for those voltage ranges in the service manual. Thanks!

 

Ted, is this what you are looking for? I posted this in a local thread yesterday:

 

That's it. Thanks!

 

Does the EVO use the idle switch? I've logged idle switch in Evoscan and have not been able to see it change states.

Also, does the desired idle TPS position correspond to roughly 13% in EVOscan? My car was setup to read 13% from the factory. I have it reading 3% right now as I adjusted it a while back trying to get the idle switch to change states.

 

Actually, that helps too. If the factory idle TPS is around 13%, that might save me from having to take voltage readings. As it is, mine is set at around 17%, which may be too high.

 

Yup, usually 12.6% to 13.2% or so ...

 

to be exact my TPS in Mitsulogger at idle logs in at 12.157

 

I don't think the Evo uses a TPS switch.

 

I didn't think so either. Anyway, I am going to attempt to synchronize TPS and TB physically first at the WOT position, then tweak the idle stop using 12-13% indicated TPS position. We'll see if that gets me to where I physically need to be to tune the rest of the idle settings electronically.

 

Is the 13% offset just something that is reflective of the range the ECU is looking (~0.6V-4.7V) for vs. the idea that EVOscan thinks the range is 0-5V?

 

It would seem that either the ECU or Evoscan converts the TPS voltage to TPS position (%), so any given reported position should correspond to a referenced voltage.

 

Its done in EvoScan.

 

Not just Evoscan. It shows up on handheld scantools as a similar percentage as well. It seems fairly primitive to be displaying a percentage of 0-5V rather than actual throttle position movement, something we would expect in the 1980's but not these days.

The ecu definitely learns its new position and uses it in its map calculations. My auto has always had issues with the torque convertor lockup, which is TPS mapped. I needed to move the point of transition a couple of percent but cannot find the map anywhere in the rom, so I resorted to adjusting the TPS sensor a small amount (still in spec though) but it had no effect. It still learned the new offset and applied it to its tuning effectively putting it back to where it was.