Mitsubishi Diamante Idle Relearn Procedure

davedave, Feb 26, 9:00pm
Charged the battery in my Oz assembled 1998 3.5 Diamante after it had been in panel shop for a week, now it is stalling and idling poorly. I understand there is a relearn procedure. I have tried the warm up, idle in neutral for 60 seconds, then in drive for 60 seconds, drive "normally" into 4th, then decelerate normally to stop. It has not improved. Any suggestions!

daryl14, Feb 26, 9:03pm
go back to panel shop and say please make my car go!

phillip.weston, Feb 26, 9:29pm
remove the intake hose from the throttlebody to the air filter housing box. With a petrol soaked rag, wipe inside around the edges of the throttle body and the throttle plate itself removing as much of the built up gunge as possible.

Over time as gunge builds up normally, the idle stepper motor is instructed by the ECU to automatically adjust the base idle speed by adding and increasing variable y on top of the base idle speed which we will call variable x.

When you disconnect the battery and therefore reset the ECU, the idle stepper motor reverts back to position x, however the throttle body is not flowing enough air at idle due to the gunge build up. Simply cleaning out the throttle body and re-resetting the ECU and let it idle for a few mins should be enough to re-adjust the idle speed.

davedave, Feb 26, 9:38pm
Thanks PW.

bigfatmat1, Feb 26, 10:35pm
I know petrol and a rag works well but CRC do a good throttle body cleaner if you prefer. Dissolves the baked on stuff quite nicely