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

[sbergman27]

Originally Posted by bronsin

Let me tell you something about engineers and scientests. They are IDIOTS just like...

Wow. Did an engineering student once steal your girlfriend or something? You may want to consider seeking help for this unhealthy obsession.

Using coolant temperature as a factor in adjusting the fuel map, ignition timing curve, or whatever, is hardly creating a "rat's nest". But you're certainly welcome to investigate your options for re-flashing the whole ECU with your own software image. Then you could set it so that only 4th and reverse were available.

You'd need the proper interface equipment and communications software. A decompiler, a compiler. Some knowledge of embedded programming. A firm grasp of the details of the Yaris' various systems. And also of the relevant legal codes for your country and province. I'd be daunted by the task, even though I'm a programmer. But you seem really smart, so I expect you'd have no trouble.

And surely *that* would be enough to get you from point A to point B on these fictitious... err... desolate Canadian roads where it takes every last drop in the Yaris' 11.2 gallon tank to get you from one gas station to the next.

But first, you might want to verify that the existing transmission control algorithm is actually hurting, and not improving, overall fuel economy. You could enlist the help of someone with a 5 spd and a Scangauge II to do some preliminary testing. Not a perfect simulation, to be sure, since it leaves the torque converter, among other things, out of the equation. But nonetheless, it would be interesting to see the results.

-Steve