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4eat to 5mt swap in '98 LGT, high idle issue...

Posted: Fri Jun 25, 2010 3:41 am
by 94.GT.Wagon
I just finished a trans swap for my buddy in his '98 LGT wagon and everything is working great except for the high idle that comes with leaving the TCU plugged in. I know this problem can be solved by removing the TCU but then the ABS needs attention. My question is can this problem be solved while leaving the TCU in place or am I going to have to remove it and then deal with the ABS issue? I've heard that the ECU simply learns away the high idle after a short while but that hasn't happened yet. I've also heard that there's one wire that the TCU uses to send a signal to the ECU telling it to kick the idle up to carry the load of the torque converter but haven't seen any info on what wire that might be. All advice is appreciated!

Re: 4eat to 5mt swap in '98 LGT, high idle issue...

Posted: Sun Jun 27, 2010 10:10 pm
by Legacy777
The idle is high likely because the ECU still thinks it's an AT. If you haven't done anything with the AT/MT ident pin on the ECU, that is likely the problem. I'm not sure what will happen if you leave the TCU in and make the ECU think it's a MT. All you can do is give it a shot.