I figured out what the manual button really does!

[ciper]

We have had many discussions about this, I wont retype everything. I will say that Im very confident in what I believe.

When using the manual button in the "3" selection your transmission chooses between the second and third gears. We all agree on this point

I saw that once you get into third over a certain speed you couldnt drop back to second no matter what the throttle was doing. This speed is around 30mph. When still in second gear you can floor the pedal and keep it in second for longer than the cut off point mentioned previously. Once you release the throttle or reach a certain rpm you will be again stuck in third until that cut off point.

It came to me while cleaning some parts I got from the junk yard. I realized that I have seen this EXACT behaviour before!


ALL THE MANUAL BUTTON DOES IS USE THE FIRST GEAR MAP FOR SECOND AND THE SECOND GEAR MAP FOR THIRD! The standard setup for driving the car in the "2" selection without the manual button is used, except that 2nd gear is substitued for first and 3rd gear is substituted for 2nd.


When driving in the "2" selection without the manual button you can experience what I mention. At 25 MPH or so cruising you can floor the throttle (or open quickly) and drop to 1st. If you are over 30 or so flooring the throttle (or changing quickly) will keep you in second no matter what. Thats why sometimes your car feels very fast while others you get stuck at the bottom of second gear.


Im pretty excited, please test this for yourself and tell me how you feel!

As a side note knowing the speed that you are "allowed" to drop to first helps you to plan your speed before a turn or other reason to slow to allow maximum accelleration afterwards.
This also relates to a topic where we tried to find out why downshifting to 1st is always so harsh...

[Legacy777]

I'll try to do some playing.....my speeds will be different since I have 3.7 gears though.

[ciper]

What I did was collect as much data as I could about how the car acts with "2" without manual button. Then I tried the same in "3" with manual button and see if I could find a difference.

You know in cartoons when a light bulb appears over your head? Thats how I felt

edit:

[Matt Monson]

Go figure...this was part of what I was coming over to "drivetrain" to try and figure out. So, this has something to do with me sometimes getting 5-7psi boost at full throttle and sometimes 10-11psi( remember I am at elevation). I will have to read more in the history you mention...

[ciper]

Im sure this is correct. In second gear you cannot shift back to first no matter what throttle position you have if you are already over 25mph. Under 25mph will shift you back into first.

This is exactly what happens in third when the manual button is enabled. Once you hit 25mph in third you can do whatever you like and the car will stay in third. If you have the throttle floored while still in second you can hold it to redline, if you release it slightly at any time though you will go into third.

I plan to make a fuel cut defender for the throttle position ECU output to the TCU to create a completely manual automatic in conjunction with the manual switch.

[scottzg]

I plan to make a fuel cut defender for the throttle position ECU output to the TCU to create a completely manual automatic in conjunction with the manual switch.

that is incredibly, incredibly, INCREDIBLY awesome. You will have most of the benefits of a manual in an automatic

Here's what I'm wondering: isn't the signal from the AT lever doohickey entirely electronic? Cause if it is, you could rig up some F1 style paddle shifters rather easily.

[MY92]

My car acts in exactly the same way