1995 SC400 TPS Issue

[LexusSC]

im in need of some advise and knowledge about the SC400 and the 1UZ-FE Specs, normal idle speed in park and in drive, normal problems you know of with the 1UZ-FE and any thing else.

But first I'll explain whats going on, recently i decided to mess with the car , very late at night i might add , and the car is my moms carr too, Yah bad idea , i know now.

but i remember taking the throttle position sensor off and just reinstalling it without any form of calibration or knowledge as to the proper adjustment of the sensor. Well it took a nose dive and would die at stops because the rpm went around from 1000 or soo to like 300 then bounced back and forth and died .

so after a month or two of that i re attempted the adjustment of it and now it idles too high ( in park 1000rpm - in drive 800rpm ).

i would appreciate any knowledge or instruction you can give me as to diagnosing this issue and solving it _on top of specs and normal operation specs of this vehicle . Its a 95 Lexus SC400 with the stock 1UZ-FE V8 .

 

[mshawari1]

What I remember is 650 RPM +- 50 for idle speed. you could play with TPS till you reach acceptable reading.

Or, Reset the ECU and fix the TPS in the middle ... use it for one day ... if its not fixed try play with ISC.

 

[4U2QUIK]

.45V ALL YOU NEED TO know....

 

[LexusSC]

how do i reset the ecu and what do u mean by fixing the tps in the middle

 

[gloverman]

I generally set the TPS so the idle switch is off with .25mm of throttle plate opening. Cheers

 

[LexusSC]

ok so i lined up the set screws on the tps with the yellow paint dots and unplugged the battery for 20mins and i drove the car til it reached opperating temp and it still idles at 1100 in park , ughh does this sound familiar or does anyone know of anything else ??

 

[stevieg]

ok so i lined up the set screws on the tps with the yellow paint dots and unplugged the battery for 20mins and i drove the car til it reached opperating temp and it still idles at 1100 in park , ughh does this sound familiar or does anyone know of anything else ??

search online for a toyota tps adjustment procedure, it involves using a multimeter to meaure voltage/resistance at a certain amount of throttle movement.

do it properly or it wont work

 

[4U2QUIK]

yup, .45v all you need to know lol

 

[LexusSC]

ok so that was done properly but it idles high still , could it be an idle speed motor like i have been told recently ??

 

[mshawari1]

ok so that was done properly but it idles high still , could it be an idle speed motor like i have been told recently ??

Yes, you could check that ISC too according to the manual resistant reading.

next is the A/C idle speed trigger.