adjusting TPS (1 Viewer)

[hurricanesteve]

had the truck back a week since HG replacement...idle was a little weird...was high, then ok, then high again (650, 900, 650, etc...a/c compressor kicking on and off exaggerated it).

I gave it a week to see if it was gonna pass on its own...too lazy to pull out the old laptop with obd2 software

anyway, tps at idle (and with engine off) was 12.5%. max open was 76.5%. i found a couple threads here saying it should be closer to 6% at idle.

so, loosened the two screws and rotated it a bit, retightened, checked again: 6% at idle and 71% at WOT. quick drive around confirmed idle is back to normal (630 or so) and smooth as silk again.

the questions: what should the % range be from idle to WOT? is the TPS adjustable in both dimensions (min and max)? when i had the screws loose, it appears to only be a cw or ccw adjustment...one dimension, range fixed?

tia

 

[CJF]

What do you mean by %'s? I thought it was just specified ohm ranges while testing various connectors on the TPS and various throttle positions? Or maybe that's only OBD1? Or maybe I'm just confusing myself as usual?

Regardless, sure sounds like you're good to go...

Curtis

 

[CJF]

it appears to only be a cw or ccw adjustment...one dimension, range fixed?

Dat's true...

 

[Rookie2]

What do you mean by %'s? I thought it was just specified ohm ranges while testing various connectors on the TPS and various throttle positions?

Ditto that.

Need rig year in sig line.

 

[hurricanesteve]

97 lx450, sorry.

 

[RavenTai]

Throttle Position sensor signal is represented differently on OBD and
OBD II data streams. OBD displays opening angle in degrees ranging
from 0° to 75°. OBD II displays throttle opening as a percentage of
wide-open throttle, ranging from about 5% to 80%.

quote is from Lexus training manual not a vehicle specific document

what does it show if you rig it per the FSM?

 

[hurricanesteve]

i ponied up the $10 yesterday for the techinfo online FSM...printed out several pages. looks like i dropped the tps below spec. says 7-11% with throttle closed.

i'm gonna go ahead and follow the procedure in the FSM on adjusting the TPS using an ohmmeter...and i'll make sure the throttle cable is within spec.

 

[hurricanesteve]

finally got some time to mess with this again.

idle got weird again (too low) after first adjustment. did the FSM test of the TPS, and everything was within spec.

adjusted til idle was at 10% per OBD2 software. drove for a few days.

two things were happening:

1) shifting 1-2 and 2-1 seemed a little "off." i think it had been doing this before, but I thought it was related to the TPS being off. similar to the symptoms reported by others: "flaring?"

2) the idle would stay high at a stop now, but i could put my foot UNDER the pedal and pull up and it would come down again.

so had an "aha!" moment. Lubed all three cables with some lithium grease.

Also, the kickdown cable was significantly tauter than the other two cables, even tho it was right at about 1mm from stopper (spec is 0-1mm) per FSM. I loosened it until it was at 0mm.

once again, seems better. put about 100 miles on it in stop and go conditions. so far, it's behaving as it had before my HG trouble started. smoother idle, shifting seems "right"...no sticky cable/pedal.

*knock wood*

 

[CJF]

T'anks for the follow-up!

Good luck,

Curtis

 

[perk]

i ponied up the $10 yesterday for the techinfo online FSM...printed out several pages. looks like i dropped the tps below spec. says 7-11% with throttle closed.

i'm gonna go ahead and follow the procedure in the FSM on adjusting the TPS using an ohmmeter...and i'll make sure the throttle cable is within spec.

Is 7-11% the same as 7-11 degrees?
Have you had anymore symptoms since you readjusted ?
Did you ever have a problem with rpms surging up and down?

I'm still trying to get to the bottom of my idling problems.

Thanks,
Perk

 

[hurricanesteve]

Is 7-11% the same as 7-11 degrees?
Have you had anymore symptoms since you readjusted ?
Did you ever have a problem with rpms surging up and down?

I'm still trying to get to the bottom of my idling problems.

Thanks,
Perk

don't think % = degrees. the obd2 variable is "% open"

the rpms do fluctuate occasionally within a 50-75rpm range, and of course when the a/c compressor kicks on and off the rpms bounce for a second or two.

 

[perk]

I'm trying to get at whether my mechanic correctly adjusted my TPS to 6 degrees from it's position of 9 degress. The FSM only describes adjusting/rotating the TPS once the throttle body is removed and using an ohmeter to detect when the sensor "deflects"? while rotating clockwise. It gives no mention of percentages or degrees.

Any thoughts regarding this would be helpful


Thanks,
Perk

p.s. By surging, I meant REVING to about 2200 than down to 1000 over and over. This problem, as well as my low (300 rpm) idle went away initially when my mechanic moved the TPS to 6 degrees. Both problems are intermittent, and have returned. The surging came back once the AC began to be used. Whenever it's acting up, turning off the engine and immediately restarting gets it back to normal (650 rpm).

 

[joker]

make sure throttle cable doesnt have any bends in it. should be smooth and sweeping all the way around. i had a problem with mine sticking near the engine end connection where the metal clamp clamps to the outer casing.