If you want a cheap scanner that will work, check out BAFX products on Amazon, I got mine for $20 around three years ago and it works great.

 

Ok, tben it has to be an OBDII system. Still surprizing that you don't have stored error codes. Try store scanner. At least that way you'll know if its a sc antool malfunctioning on you or the interface somehow is gone bad.

 

Naeos.....Thanks for that info on the BAFX scanner. However, I think your Montero is a 2002, and since my 94 is on "the border" of being either OBD 1 or OBD 2, it may not work. Guess I first need to drive it to the parts store and see what they say, and if their scanner works on it.

Hunter.....Yep, it very well could be just a defective scanner I was using.

Will post what I discover.

 

Ok, back to the No Proper Idle. I've been looking more into it, trying to figure out how to test our IAC. Among different things I found couple interesting videos explaining how Idle Control valves work. One is for a Toyota valve and a slightly different design than the one we have in our Mitsubishi, but I think it will be helpful to see the operating principle, mechanical breakdown and testing of the IAC.
Second video is for testing what looks like our style valve. It has 6-pin connector, so it will most likely behave similar to our IACs. I hope it will give you some ideas of what to check on your valve.



One more useful video from Scanner Danner. This guy is amazing in his troubleshooting of all sorts of electronics on cars. This is more related to what I think is going on in 1960StudebakerHawk's Montero - high idle is a secondary manifestation of some other issue:

 

Hunter.....Great videos you posted. I like the middle one showing how to test the 6-prong IAC......I will be doing this test soon.

I cranked up the Montero today, and she did not want to Idle when cold.....I had to feather the gas a bit to prevent it from stalling out. After driving and warming up, the idle was working.......would idle around the second "click" on the tachomenter, which I think is around 700 rpm. I drove to the Advance Auto to see if they would bring out their scan tool and try to read the computer codes. The guy said that due to this darn Korona stuff, they now do not allow this. I asked if he knew if I had the OBD 1 or OBD 2 on the 94 Montero, and the just said that "all cars starting at 1995 are OBD 2".....so, he assumed that my Monty is an OBD 1. But I think he is just thinking that 1995 is the beginning date for all vehicles, but I thought Mitsubishi went with OBD 2 in 1994......I need to verify exactly which one it is so I can order the correct code reader.

Another note.....After letting the Montero sit for only 10 minutes, when I started her up, she once again did not want to idle. I will eventually figure out this problem.

 

Hunter.........Just had another thought: The throttle body has coolant lines running up to the area where the IAC "idle control valve" is located. There is a bi-metallic spring (I think?) that is supposed to expand/contract which also allows more or less air to help with the idle. When I did the thorough Throttle Body cleaning, those 4 phillips screws were so tight that I just left it alone. I did verify that it was not clogged by spraying penetrating oil in the lines. Do you think that a "stuck" spring up in this coolant area would be enough to cause the idle problem? I personally doubt it, but wonder what you think.

Here is a pic of the Throttle Body base where the IAC mounts. You can see the coolant lines on the bottom, and then a brass-looking valve (or something) down inside where the IAC shaft goes in/out. Do you think that brass flat "thing" is another "valve", and if it is stuck it could prevent the IAC from actually working?



Here is another view.....4 phillips screws hold it to the throttle body:



In this pic you can see the factory white paint on another phillips screw that holds what appears to be an "adjusting screw" (to left of the yellow tape):

 

I know when I cleaned my throttle body I took out that little plastic flapper valve (dunno what it's called) and cleaned it thoroughly, it was so junked up with carbon soot that afterwards it idled better than it did. I memory serves me right, there's a spring or something in there as well. This system works in tandem with the IAC so it stands to reason it needs to be cleaned. I would have mentioned it earlier but since you mentioned you cleaned the TB I just assumed this was done as well.

 

I do not know is the bi-metalic spring/valve could be stuck. Anything is possible. If the screws holding the cap are super tight, you need to get manual impact screwdriver. With it, you can pop loose those pesky screws without mangling up the phillips heads. Take it apart and see what else you can clean/free up.

 

Naeos.......Yep, I wanted to remove that coolant assembly piece, but was too lazy to stick the TBody into a big vice so I could use an impact wrench/hammer to break those 4 phillips screws loose. DOHHHHH! But this coolant "valve" only sees incoming fresh air that comes through the IAC, so there should be no carbon built up in this one (I think?). But it still could be "stuck" and causing issues. Might have to take it all apart again.

On the other side of the Throttle Body is the EGR which does see a ton of carbon/oily crud come thru from the engine on its way to the Throttle body.....I did remove and clean that one.

 

Hunter......Yep, this will be on my "to do" list. But I was still hoping to verify if this rig is a OBD 1 or OBD 2, and then get a code reader that works......maybe it will tell me something.