Experimenting with bypassing the AT 4th gear prohibition when cold

[eTiMaGo]

Originally Posted by bronsin

Since manual transmissions can be shifted into fifth right away whatever the lockout feature is "helping" doesnt apply to them. Are manaul transmission cars suffering premature failures because of this. Seems unlikely.

Actually I am not sure if the AT cars do this to the same degree, but the ECU runs the car rather rich while it is in warmup mode, for the same reason of getting the cats up and running...

[CTScott]

Originally Posted by eTiMaGo

Actually I am not sure if the AT cars do this to the same degree, but the ECU runs the car rather rich while it is in warmup mode, for the same reason of getting the cats up and running...

The Yaris sure does. Last night, after about a 5 mile run with the resistor in to fool the ECM into thinking that it was still in the "cold" mode, I pulled into the garage and noticed that the engine was revving. I looked up at my YarGauge and saw that it was at about 1600 RPM and the AFR was 13.7 (whereas after warming up it always sits dead on stoich when idling). I pressed and held my warm up button, and the RPMs and AFR immediately returned to their normal state.