Tweak tip for auto Sc shifting!
09-01-07, 08:22 PM
#1
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Tweak tip for auto Sc shifting!
Sorry to everyone who already knows this, but I just figured it out and wanted to share with everyone else. 
I was messing with my TPS sensor to try and fix a hesitation and I stumbled across this trick.
When you put your SC in gear it can either grab hard and jolt the car, or it can drop into gear smoothly. For a harder grab rotate the TPS clockwise. For a softer engage, rotate it counter clockwise.
There's more to this though..... If you want your Sc to shift LATER in the RPM band without having to hold your foot down on the floor, rotate it counter clockwise. This will increase the shift point of the transmission to a higher RPM than stock.
I discovered this when my Sc would prematurely shift into second gear. No matter how hard I kept my foot on the throttle the damn thing would shift to second at 4000 rpm's. Tonight I was looking around and decided to try moving the TPS since I had replaced it 2 yrs ago. Sure enough, rotating it either made it engage into gear harder and shift sooner, or drop into gear smooth as butter and shift much later in the RPM band. (dependent of how much you rotate it).
If you want to tweak your Auto tranny with just two screws, this not only makes the shifts more enjoyable, it allows you a broader power range without having to keep your foot to the floor.
Now with video: http://www.youtube.com/watch?v=n3-DfW2ouGA
I was messing with my TPS sensor to try and fix a hesitation and I stumbled across this trick.
When you put your SC in gear it can either grab hard and jolt the car, or it can drop into gear smoothly. For a harder grab rotate the TPS clockwise. For a softer engage, rotate it counter clockwise.
There's more to this though..... If you want your Sc to shift LATER in the RPM band without having to hold your foot down on the floor, rotate it counter clockwise. This will increase the shift point of the transmission to a higher RPM than stock.
I discovered this when my Sc would prematurely shift into second gear. No matter how hard I kept my foot on the throttle the damn thing would shift to second at 4000 rpm's. Tonight I was looking around and decided to try moving the TPS since I had replaced it 2 yrs ago. Sure enough, rotating it either made it engage into gear harder and shift sooner, or drop into gear smooth as butter and shift much later in the RPM band. (dependent of how much you rotate it).
If you want to tweak your Auto tranny with just two screws, this not only makes the shifts more enjoyable, it allows you a broader power range without having to keep your foot to the floor.
Now with video: http://www.youtube.com/watch?v=n3-DfW2ouGA
Last edited by O. L. T.; 10-21-08 at 01:49 PM.
09-01-07, 08:47 PM
#3
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It'll work on any sc400. I have only tested on ODBI, non vvti.
I knew it would affect it, but I didn't know it was a two stage thing. I was aware it would change how harsh it engages, but the change in RPM shift was a bonus.
I knew it would affect it, but I didn't know it was a two stage thing. I was aware it would change how harsh it engages, but the change in RPM shift was a bonus.
Last edited by O. L. T.; 09-04-09 at 12:10 AM.
09-01-07, 08:58 PM
#4
Lexus Test Driver
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O.L.T, can explain what exactly to do, loosen and rotate as far as it will go? If this fixes the jolt when I put the car into drive, I might just buy you a beer!
Last edited by FireCode; 09-01-07 at 09:13 PM.
09-01-07, 08:59 PM
#5
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Hey OLT, sorry for jacking the thread, but you see the 2 vacuum line/hose towards the bottom?
Well, I was checking my engine bay today and I noticed that those 2 lines are disconnected.
Do you have any idea where it goes? Try to look, but it was kinda dark outside.
Well, I was checking my engine bay today and I noticed that those 2 lines are disconnected.
Do you have any idea where it goes? Try to look, but it was kinda dark outside.
09-01-07, 09:06 PM
#6
Pole Position
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can u describe in more detail what i need to do to perform this? do i just loosen the two screws around the black piece and then rotate it? or is there more involved? i want to have a smoother grab but i don't want to screw up something by doing it wrong.
thanks.
thanks.
09-01-07, 09:22 PM
#7
Keeper of the light
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Just for kicks, you should all make note of where it sits before you move it.
Last edited by O. L. T.; 09-01-07 at 09:36 PM.
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11-24-07, 10:58 AM
#14
Bring it up. OLT, could you please specify what part you are talking about? Are you talking about at the base of the Throttlebody where that "metal pipe" is extended out and that black *sensor* is? I'm still a little confused, and more pics on adjusting would definitely be helpful. Thank you.
11-25-07, 05:07 PM
#15
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If you have TRAC control, the tps sensor on the left is for the traction control system (sub-main tps) and the one closest to the throttle body is the main tps sensor. The main tps sensor is the one that this post is in reference to. It works great. No more "shock" when going from park to reverse. Do you know the underlying cause of the harsh engagement?