How Do You Keep An Auto Trans In The Highest Gear?

[CTScott]

It would just be a matter of switching a resistor in parallel with the engine coolant temperature sensor. The ECM sees a dead short as 140C and a full open as 40C, so it would just be a matter of selecting the correct resistor value to put it in the normal warm range. I am packing to head out of the country tomorrow morning, but I'll do some experimentation when I return.

[bronsin]

Originally Posted by CTScott

It would just be a matter of switching a resistor in parallel with the engine coolant temperature sensor. The ECM sees a dead short as 140C and a full open as 40C, so it would just be a matter of selecting the correct resistor value to put it in the normal warm range. I am packing to head out of the country tomorrow morning, but I'll do some experimentation when I return.

:thum bup:

:w 00t:




If this works it will be so awesome!


Maybe you should postpone your trip and get started working on it right away?

[Kal-El]

Bronson, considering you opened two threads about the auto not doing what you want, it looks like you should've bought a manual.

[bronsin]

Originally Posted by Kal-El

Bronson, considering you opened two threads about the auto not doing what you want, it looks like you should've bought a manual.

I never would have but my feet are numb and get painfull pushing in a clutch. Had to go auto.

Say do they make a hand clutch adapter for handicapped people? I would be so there.

[sbergman27]

I wonder what other effects might result from tricking the ECU into thinking that the coolant is always warmer than it is.

Sounds like a bad idea to me.

I'm not that familiar with the Yaris' control systems, or what is controlled by the ECU and what is handled by discrete systems, but...

Any strategies that the ECU uses to optimize fuel economy and driveability during warm up would likely be thrown off. And at normal operating temperature, the radiator fan might run continuously. (Or is that independent of the ECU?) And the ECU might go into emergency measures (timing advance? idle speed increase?) to control the "overheating" situation it erroneously detects.

Rather than messing with the ECU's sensor inputs, I think I would be more inclined to investigate the rationale behind the temp lockouts in the first place. I suspect they are there for a good reasons which we might agree with if we knew exactly what they were.

If the engineers who wrote the control software are "morons", I'm not quite sure what to call the person who messes with fundamental sensor inputs, like coolant temperature, without taking some time to think very carefully about the possible repercussions.

-Steve