Quote:
|
Originally Posted by rmjjensen
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?
|
My understanding of what as you state occurs, is that short repetitive pulses of say 250 ms, will not cause a kick down, whereas a longer pulse or pulses will. On this basis, continuous pulses not exceeding say 250 ms, will result only in constant power mode, which is what is desired .
It would not be difficult within the TCU, to separate two such individual signals, so that it would appear that a RPM signal would not be required in respect of the original arrangement.
You have certainly carried out some interesting experiments and the information you have provided is very much appreciated.
