I changed my battery on my Mits. Montero Sport 1998. The car is not idleing and I've put about 5 batteries in this car now so I know this is a common thing. The last time I took it in the mechanic said you have to go through a complex reset procedure in the car whenever you change the battery so that the car will relearn its idle position. He explained to me then but I don't remember it. I do know it was something like you turn on the hazard lights and the parking brake and the main headlights on and other stuff and you have to turn the AC on full blast, do x for so long, y for so long, and viola. It was crazy...even the mechanic said it was the crazest thing of any of his car reset procedures. The car has to have an "up-idle" position for the A/C and it has to calibrate this when the power is removed from the computer.
I hate to have to spend $100 everytime I change the battery. Does anyone have this procedure...I can't believe Mit. did not put this is the owners manual. I want to print it out and tape it to my manual.
Right now, unless the A/C is on full blast the car won't idle.
I read alot of threads on the Internet with people having the problem and no-one seems to be writing what the procedure is. The mechanic says the key is the procedure...if that doesn't work, then, and only then do the clean the throttle bottle.
Last Edit: Aug 23, 2010 9:44:53 GMT -5 by codeaholic
Post by codeaholic on Aug 23, 2010 10:26:19 GMT -5
There is a computer reset procedure that allows the computer to relearn its idle position "WITHOUT" cleaning anything or taking a single screw out.
My battery only lasted 2 years...and I've had a clean air filter in there the whole time, there is nothing wrong with the throttle body. I could clean it all day long and it won't solve the problem.
I have to train the computer where the high and low idle position is. It learns this position based on a procedure of dragging the battery down to its highest "load" position with the A/C load as well.
The mechanic was very plain about this last time. You only need to clean the throttle body when things are way out of whack and its dirty.
Last Edit: Aug 23, 2010 10:27:22 GMT -5 by codeaholic
Post by limitedmonty on Aug 25, 2010 21:29:52 GMT -5
hmm i have been a mitsu technician for over 2 years and none of us have heard of this??? if you have already cleaned your throttle body and it dont idle right, than you need to adjust your idle/biss srew on the throttle body. and if still no change, your idle speed control motor is bad on your throttle body just my $.02
Not sure if this reset thing is true but hear me out.
I just did my spark plugs and wires the other day on my 3.0 (97 LS) and man did it need them. The electrodes on the spark plugs were almost non existent. At 170K I am wondering if they were ever done at all. Seeing as I just got this vehicle I wasnt too sure.
Anyway, it was actually running fine before the change (big difference in power after) it idled and accelerated OK for its age. Here is the wierd part. After the tune up it dies at idle sometimes. I watch it as I stop at a light or put it into park and it's idling at around 300 rpm.
Now the only thing I can think is that when I disconnected the battery and did my tune up the computer doesnt know how to react at idle anymore. Can this be true? I'm waiting for it to "recalibrate" itself. I'll repost if this happens, otherwise I'll be looking for a way to make it re-learn its idle I suppose.
After a battery replacement some vehicle may experiance stalling and or poor idle. This is caused by the PCM loosing its learned idle position. The only way to relearn the idle is to allow it to idle if it won't just keep restarting it untill it does then cycle the A/C and headlamps to put a load on the engine. there is no reason to adjust the SAS screw after a battery replacement. just give it time it will relearn.
Post by montynewb on Sept 16, 2010 19:37:53 GMT -5
It's been almost a month now and it still dies sometimes and low idles at stop lights and such. Sometimes if I put it in park and let it idle for a bit it will die. Should I disconnect the battery again or something? I have never known a vehicle to act like this just by changing a battery.
It should have relearned the correct idle set by now. I think you have other issues and its just a coincedence that it happened after you replaced your battery. The only way to be sure is to hook up a Mitsu. scanner and check the IAC step then readjust the SAS if that doesn't do it then you may have a large vac. leak or something else.
Post by snowaddict91 on Sept 17, 2010 13:06:28 GMT -5
have you tried disconnecting the battery overnight (or for a few hours), then start up the car with no a/c or lights on, let it go for 10-15 mins, then 10 mins w/ ac and lights on. Usually works for me. You may have stuff thats real dirty that needs cleaned though for a better idle too
Just as reference for you, I have the same car, a Mits. Montero Sport LS 1998. I replaced my battery just two weeks ago when I had my alternator replaced aswell and didn't need the car to re-learn anything at all for idling. However my car did experience terrible idle issues way before my repairs when at stop lights and embarrassingly at stop signs and would shut down more times than not. I took the advice of spraying my throttle plate intake valves even though it looked very very clean on the outside but dirty in the inner area. It made a miraculous difference. I even used a tooth brush to clean all around inside the valves which was dirty. I haven't had a stall engine shutoff or idle RPM drop since. Just FYI since we have similar model car.