KRos_+

I have been searching all nite and cant find what im looking for. I need more TPS reports for Lumberg! lol...

Im wondering if anyone can tell me why i cant get a steady reading from my Throttle position sensor while it is in closed position(0.0mm) between ports VTA and E2? I get a reading that fluctuates between 2.20 and 2.40 in the 20k ohms range on my multimeter. So that would be 2200-2400 ohms if my math is correct?. Its making me think that either my throttle plate is dirty and not letting it close to get a steady reading or the TPS is bad. All other measurements are steady and check good to fsm spec. Ive been fightin with idle problems for so long now. ANy help is much appreciated. Thanks

peckinpah

If your reading is jumping around, the TPS is bad. That's what mine was doing before I replaced it. The new one stayed rock steady when I tested it with the multimeter in various positions.

And if your engine RPM's are also stumbling from time to time while driving down the freeway, then your TPS is most certainly worn out.

KRos_+

Thanks peckinpah! Good to have another point of view point to the same thing.

Now what about disconnecting it completely? Temporarily until i can afford a new one of course. Ive read that engine will run without it and just get bad mileage and overwork the cat. conv. And ive also read that it should idle better when disconnected. But when i tried disconnecting it the idle went up way higher ( over 2k rpms), I cant remember if this was during the cold start/ warm up period. So im gonna try again and see what happens and post back here when i do.

Right now it will start up and idle around 1100 rpms but as it warms up it climbs to 2k rpms. Once fully warm(op temp) it hits the fuel cut off and starts to surge between 1600 rpms and 2000. Constant surging. And when brake is pressed it drops to 900 rpms and surges to 1200 then back to 900 and so on.....Does this sound like a bad TPS?

5runner

yes i just replaced mine and at first i did not adjust it right and it surged really bad but i readjusted it and it is all better now

KRos_+

Thanks 5runner, that makes 4 ppl that know toyotas telling me to change it.

The more i think about it, Either my friend sprayed brake cleaner on my tps trying to check for vacuum leaks or i spilled too much coolant on it changing the t-stat. Because both those things happened within the same time period, within a few days of each other. And soon after that I started having idle problems.

THanks to everyone on yotatech, I have since then learned not to use brake cleaner for vac tests(use propane, carb cleaner, startng fluid, etc.). And to remove the TPS before spraying anything in or around the TB since it is not a sealed unit and can be penetrated and damaged by water and chemicals.

Im hoping that its just my tps causing my problems and not a dreaded vacuum leak or other issue that can be hard to locate. Im goin to call the dealership and get a price from them. The TPS thats on there is stock toyota brand, probably orginal since eveything else has been so far. It wasnt maintained very well. Wouldnt be a bad idea to change it and adjust it anyway. ANd clean the TB while im at it.

I will post back with my results asap. Keep posting if anyone has any comments or advice. thanks!

KRos_+

oh btw, i havent tried running it with the tps disconnected. From what ive read it doesnt sound good. Anyone else wanna chime in on that ???

matt92yota

im not sure what you mean when you say it doesnt sound good but i run mine with the tps disconnected and it runs perfect

KRos_+

Thanks matt, ill give it a try and see what happens. Hopefully tomorrow

KRos_+

How high will your idle get when it is cold outside? During the warm up period. Mine used to idle over 2000rpms to warm up is that normal?

Cody91

The Highest I have seen mine (3vze, 5speed) at 0oF was 1750RPM's 1000 Higher than idle takes 91/2 min to warm up to running temp and settles at 750 RPM's with the heat on mid way So its nice and warm to go to work.

KRos_+

I tried running it with the TPS disconnected and no change in idle. So i plugged it back in and jumped the Diagnostic box terminals E1 and TE1 (with a paperclip) and the rpms dropped audibly. So that tells me the TPS is working properly and to move on to other possible causes. IACV is next culprit along the VAFM. Gonna test resistance on VAFM now. And read up on testing the IACV with duct tape.

With the TPS disconnected the idle does not surge. Im assuming this is because the ECU has no way to tell where the throttle is. Once plugged in it surges non stop between 2200 - 1600 rpms.

KRos_+

When testing the IACV by duct taping the holes, do i tape the hole in front of the throttle plate and the hole behind the throttle plate?(both associated with the IACV) All the other threads are so old the pics are gone! Please help as im goin to try this asap!

beateryota530

Have you tried to see what the 02 is doing? The FSM has a detailed self check for the 02, it may be working with a faulty TPS to throw off the ECM

KRos_+

No i havent checked the 02 (oxygen sensor im assuming u mean). I have been thinking about it more and more though. I havent wanted to crawl around in my muddy/melted/semi frozen driveway underneath my truck to test that yet. Ive been trying to do the test that i can in the engine bay when i have daylight and, weather permitting ( which has been unseasonably warm and very little snow ). Im glad since my truck is down and the vehicle im driving now sux in the snow! It can wait until my trucks running right!

The O2 sensor wasnt bolted on when i bought it. Was held on by gravity on the studs and rattled like hell all the time. I bolted it down and noticed it was kinda beat up from bangin around. Might be time for a new one anyway but ill check it out first. No sense in buying things i dont need.

Ive read up more about the IACV and how to duct tape the hole in the throttle body to temporarily bypass it to see if its working properly. Im gonna do that as soon as i can and post back here with results. Im just hoping i get it figured out soon it needs to be driven!!!

Keep posting with any other thoughts! Thanks

KRos_+

Also, when i tested my tps again i was getting a different reading then before, so it may be faulty. not giving the same reading all the time even though reading is consistent when testing at different times/days. If anyone follows that lol.

And like i said, when jumping the te1 and e1 terminals the idle drops audibly which means the tps is set at idle/ closed position and working properly. Am i correct on that?

Another thing is when i disconnected the TPS it would start up cold around 1100 rpms and slowly but steadily rise to about 2200rpms and never comes down even when warm. Idle screw all the way in all the time. Which is the same thing it does with the tps hooked up EXCEPT that it surges from 1600 to 2200 when tps plugged in and engine warmed up. Does this tell anyone anything???

One more thing, HAS ANYONE ever use a colder t-stat? (i.e. 180F / 82C) And then had any issues like this? I was thinking that maybe the enging coolant temp sensor isnt reaching the proper/factory temp due to the colder t-stat maybe opening too soon or something. ANy ideas on that one??

Thanks again guys!!

KRos_+

Anyone??^^^^

KRos_+

Turns out duct tape on the AAV hole in the throttle body brought my idle down to factory specs 850 (+/- 50). WHich means that my AAV isnt working properly, possibly from lack of coolant flow. Im gonna remove the TB once i can get into a garage to work on it and clean everything really good. I may remove the intake manifold as well and clean it because inside is caked with carbon build up probably from 20yrs of driving. Noticed when i was cleaning to put on duct tape.

Duct tape is a temporary fix and will cause it to have NO cold start high idle. So id let it warm up a bit if its cold outside so no damage is done. A new AAV or TB is very expensive so this may be a long term temporary fix for me. Thanks to yotatech and a few other sites, I would have never figured this out without U guys!

Heres a site i referenced along with just searching IACV in Yotatech:
http://www.wildyoats.com/vbulletin/s...t=weird+idling

GLad to be back on the road!!!!!!

Ken Richards

I had a Idle around 2000RPM the when my truck warmed up it went down to like 1000RPM. So i messed with the TPS look at some info online. People said that TPS hardly ever goes bad. And it seemed like a IACV issues. so i hear that you need to adjust some jap cars with the IACV Screw inside the IACV. so i did, in inside the back plat and i tuned it down all the way then screwed it back up 3 or 4 turns back up. the also a adjusted the Idle screw. Now I get 1200RPM on cold start and 1100RPM on warms up. it fixed yhaay. I you dont know what im talking about watch this video: http://www.youtube.com/watch?v=L788jKEVblY