[rmjjensen]

Originally Posted by svxistentialist

Mike
Can you throw some light on this question for me?
You described using a pulsed or interrupted 5V signal to the TCU pin for the TPS signal. You may have used a voltage divider to provide 5V, and interrupted the 5V using a 555 timer.

Now you say this genuinely works, and turns on Power mode.

However, in your earlier descriptions, you mention that showing the TCU this WOT voltage also sends the gearbox into defcon 5 mode, i.e. it activates kickdown to the lowest gear.

Can you please verify if this is the case? If the TCU needs to see variable voltage there on that pin, so it can decide when to activate kickdown, then this applied fluctuating 5V to the TPS input pin will give Power mode OK, but may also apply kickdown full-time, which is a little less desirable for those who want to live.

What's the story? How did it work for you?

Thanks

Joe

Sure ...it's not necessarily sending +5V to the TCU that initiates power mode. It's the theory that power mode is engaged when there is a sudden charge in throttle (TPS). Pulsing +5V to this wire will make the TCU think you keep flooring the gas pedal ...then letting off ...flooring it ...letting off. Now, if you physically do this in the SVX, you'll get the TCU in power mod, but you'll also be driving like a moron and get engine surges and wouldn't make any sense.

The 555 Timer does the TPS blips into the TCU while you maintain control of the engine by way of the physical accelerator pedal (TPS signal to the ECU).

Blipping the TPS wire to the TCU with 0 -> 5 -> 0 -> 5 -> 0 -> 5 does not cause the transmission to kick down gears. It depends on the length of which +5V is applied. If it's for 250 ms (for example) there's not enough time to kick down gears. Now if you maintained constant (or long period of time) +5V to the TPS input, the TCU will kick down ...it will think, "what the heck? this guy is flooring the car, but the RPMs are barely increasing - let me kick down a gear cuz this guy wants to MOVE."

Gear changes are determined more by the RPM signal input into the TCU (which we are not changing).

Does this help?