apparently this subject's been around for a while (been reading through old posts)
here's a thought.
I *believe* this is how our system works, if I'm wrong, someone chime in.
There is a TPS signal coming from the accelerator (For arguments sake, let's call it 0-5 volts)
That signal runs to the ECU, which controls fueling (more throttle = more fuel)
That signal also runs to the TCU, which controls shifting (more throttle = lower gear)
I'm thinking of a simple electronic circuit you could use to fool the TCU:
the circuit starts with a 3 pin, 2 way switch. When the switch is in the "normal" position, that 0-5 volt TPS signal goes to the TCU as normal.
But when the switch is in the "other" position, you can use a potentiamteter to "trick" the TCU into thinking your "flooring it" when your really not.
55 MPH on the floor would be... what..... 3rd gear? 4th gear?
if this idea holds water, you would be able to force 3rd/4th gear, and have your throttle at less than 100%.
basically giving a separate TPS signal to the ECU and TCU. It would take some trial and error, but I bet we could come up with some simple resistor values that would make a reliable solution that works that we could all use.
We would basically end up with a secondary over-drive button.
the stock OD button disables 5th gear: this OD button / switch would disable 4th gear.
So basically, your towing up a big hill with a lot of weight:
Right now your choices are:
Foot to the floor, 70 MPH, 3,700, too much rpm, too much heat.
80% throttle, 37 MPH, 1,900 RPM, *&^^&* I hate my shift points.
IF you could fool the TCU to thinking you're on the floor, when your really not, on the same hill, you could have:
80% throttle, 57 MPH, 2,900 RPM, perfect.
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