Tweak tip for auto Sc shifting! - Page 4

schwarz · 10-22-08, 12:23 AM

For those of you that have done this, what was your idle RPM before adjusting the TPS and then after? Or does it not change at all?

O. L. T. · 10-22-08, 12:57 AM

Didn't do a thing to mine any of the 30 or so times I've screwed with it. Just made it drop into gear smoother and changed the shift behavior.

KrazeMatik · 10-22-08, 01:12 PM

just tried this today the RPM does idle higher when the car is put in park...the engine sound more louder then normal.... and when i have the car park then put into drive the car JERKS EXTREMALY hard.... but when i reverse to back up then put into drive its normal....

breakb · 10-22-08, 04:42 PM

fawk maybe that's why mine is messed up. anyone know how much it'll cost to re calibrate um den? that might be the solution to my problem...

peace out

IS_250 · 10-22-08, 07:06 PM

Quote:

Originally Posted by breakb

fawk maybe that's why mine is messed up. anyone know how much it'll cost to re calibrate um den? that might be the solution to my problem...

peace out

just follow the directions here:

http://www.lexls.com/tutorials/EFI/tps.html

its not too bad...

FunkMonkey · 11-18-08, 11:56 PM

Well I found this thread while searching possible problems with my transmission after having transmission flushed (see rant in maintanence) but my question is, is this tweaked during a transmission flush or is this sudden jerking into gear on cold starts a problem from having my tranmission serviced at a car wash?

I plan on doing this tweak but will I only be putting a bandaid on something that could turn out more serious in the future???

over40driv · 10-22-08, 04:46 PM

Tried the clockwise turn on my TPS today, just enough to make a diff. It idles to high, but seemed to shift better. I tried to set it back and then the idle was to low . Going to split the diff. next to get back to 800 RPM idle.

RedPhoenix · 11-19-08, 07:51 AM

only problem I had with this is that counter clockwise would make my car feel like its dragging when i was letting off throttle/cruising... and when it push on the gas a little, rpm's would jump up like 300... and jerk the car. didnt feel right. I will keep messing with it...but... I will use the multimeter trick to get it just right.

yihaw · 11-20-08, 09:49 PM

jesus thank god i read the whole thread first. if it aint broke dont fix it

b1ackhawk · 08-23-09, 10:20 PM

so would this have a similar effect as adjusting the line pressure via the adjustment screw in the trans?
Would there be any adverse affect to raising the line pressure via this method other than a harder shift?

krippled · 09-02-09, 06:35 PM

Here is the right way of getting the best result to this thread. U have to fix the problem. There is only so much you can cheat on things. Thinker vs worker. Let's not over think here's what I did to get the jerking out. I have a 95SC400 with 152,000 miles. No pain no gain spend the money and do it.
1. drain the tranny fluid twice with the OEM tranny oil. 2 months then drain it again. on the fifth month I change the tranny filter drain regularly no flush. Sometimes old tranny don't react well on flushing. Fluid is not that expensive just keep on changing until its clean.
2. Tranny mount. Again don't think about it just do it.
3. Engine mount. Just do it.
4. Throtle body cleaning with 4$ gasket don't forget to clean the passages not just the throttle itself.
5. Replace all the vacuum hose that are hard. I just replaced them all some of them are crack on the bottom and u can't see.
6. Clean the MAF or Mass whichever u have. Proper air flow provide good readings for the tps to position it self the right way.
7. I recommend putting the original air filter cover if u have after market injen air intake. I left the big tube one but remove the open air cleaner and replaced it with the OEM covered filter. I don't like to manipulate with the air metering system. Unless you have turbo and other mods then it shouldn't matter.

If u still have some money left do a full tune-up. At 100,000 mile who are u kidding trying to get away replacing these parts? FAce the fact quickly and save some money to replace these items. 1-5 cost me 450$ in parts OEM.

TPS I agree. It's electornically controled. without a proper tool to read the proper voltage for adjusment ur messing with 100's of engineer from Denso or Toyo that you are better than them messing with it mechanically.

djl · 09-02-09, 07:22 PM

Bad idea to tinker with the TPS. My SC400 check engine light came on (code was TPS related) when I took the throttle body off for cleaning and played with the TPS mounting screws. Had to follow the service manual using feeler gauges and a Fluke multimeter to set it back to factory specs.

1siksc · 09-03-09, 08:17 AM

Thanks O.L.T. My car has always been shifting hard into D since i've done the swap... Not anymore!

SC400DAVE · 10-19-09, 01:44 PM

Toyota spent 100 million in Research and Development on the SC400. I think I would rather trust there settings.

stevechumo · 10-21-09, 12:21 AM

The reliable way to make it shift better is to take the tranny valve body to the tranny performance shop who knows how to modify it. They can make it shift as hard and as fast as you want to, while you'll gain the accelleration time for sure. That's what they call putting the shift kit in the tranny. It'll also help the clutches to last longer.