I finally found what I think is a decent code reader, which does both OBD 1 and OBD 2......hopefully it works on my 94 Montero:

Innova 3140g Code Reader, ABS, Bluetooth & Live Data-OBD2 Vehicles OBD1 Coverage

 

That looks like a really nice code reader. It will do live data too, which helps a lot more than just knowing you got a PXXX code set.

 

Hunter.......Well, I got this Innova 3140G, and it was supposed to read OBD 2 and OBD 1........but it does not work on Mitsubishi vehicles. You would think that they would list on the box what OBD1 vehicles it will work with. So now I am back at square 1 in locating a code reader for these pre 1995 Monteros.

Does anyone have a code reader that will work?

 

Idle Air Control valve update: After installing the $127 IAC from Rock Auto, all was fine for a couple months. But with less than 250 miles driven on the Montero, this IAC valve failed. I just ran a test on it, and there was no Ohm reading between No. 2 & No. 3 terminal. No clue what caused its early death. Could the computer be sending too many volts to it, causing it to fail?

 

*********************Like a good horror movie, the killer says "Im back!"*********************
Update on all these IAC problems:

My 94 Montero was running fine with the "loaner" factory Mitsubishi IAC from my other 94 Montero. She was starting up and idling good the entire time for a couple months. Then, suddenly the "no idle" issue returned about 2 months ago. When starting up (engine cold), there was absolutely no idle.....the engine rpms would just fall back to 0 and the engine would die. After driving the car for 10 minutes on the highway and she was fully warmed up, she would idle fine. So, I have been just feathering the gas pedal after start-up to keep her running.

Today I had a few minutes to dig into the IAC once again. I removed the "loaner" IAC, and did an OHMS test on it. All pins read the correct 30 ohms, except for the same two pins that failed on my first IAC. These pins were reading only about 5 ohms. I just installed a new IAC, and now have that "high idle" problem......she idles around 2000 rpm. So, I will disconnect the battery and then just start driving it and hope the computer will re-learn this IAC, and the idle will gradually return to normal.

Question: It seems odd that the same two IAC pins would be failing repeatedly. I am going to predict that the new IAC will also fail, and it will be a failure accross these same two pins. If so, does that point to an ECM problem.....maybe sending way too many volts to the IAC, and burning it out?

 

Yes, kind of looks like some issue with control voltage. What can be causing it? No idea. Could be PCM, or can be an intermitent short somewhere in the harness.

 

Hunter.....Thanks for your feedback again. I think the ECM (engine control module) is behind the passenger kick-panel.

I forgot what PCM is......is that Powertrain Control Module? Where the heck is that creature located?

I had been thinking of getting another ECM and swapping the old one out......you think that should be my next step, as opposed to dumping tons of money into new IAC units?

 

ECM = PCM. Different name for the same animal. At this poibt it might be worth trying a replace me,t, but I'm still struggling to figure out how is it possible for ECM/PCM to send significant over voltage to a single component. There is no volrage step up (increase) in the computer brain. You'd think if over voltage was the culprit, other components would be affected.
BTW, did you ever test voltage output from your alternator? Voltage regulator is the only component that can produce "incorrect" voltage output.

 

Hunter......Okay, PCM is same as ECM....thanks for clarifying as I cant keep up with all the gizmos in these electrical systems. Since those ECMs are pretty darn pricey, I might just try removing one from my other 94 Montero and installing to see if it makes any difference. If it solves the problem, then I will have to look for another ECM.

Last time I checked the alternator output, I think it was around 14volts. I will have to check again. Sure would be cheaper to replace the alternator as opposed to the ECM. But even if its the alternator, its still seems strange that the same part of the IAC is going bad every time.......of the 6 pins on the IAC plug, it is consistently the same 2 pins that are showing failure when measuring their Ohms.

 

Hey man, im with you, same issue, yesterday my monty started to drop dead if i take the foot out of the gas pedal, if i put the gas and keep it pushed over 1k revs it works just fine, as soon as i remove the gas... it goes dead, it started suddenly. If you find out what was the problem you will be the hero! ill try to start testing tomorrow as i had to leave home... but hopefully it is just to replace a part.

i was doing some window regulator replacing tho, so maybe i did a short... dont know. Do you happen to know which would be the best SCANER tool to check this vehicles?

Cheers!