hey guys. finally got around to replacing my TPS this weekend, oem part. i used the FSM for installation, and now im kind of having a nard time chasing the right idle. when i first started her after the install the idle was at about 1000, so i just turned the idle adjust a little to bring her back down to 750. now it seems like every time i start the truck it has a different idle speed. today it started cold and idled at about 750 then dropped to about 500 after it warmed up. suggestions are welcomed here, for the moment im just slightly tweeking the idle adjust to try and zero in. truck is 87 runner, 22re 5sp all stock engine .

on a fun side note, when i was wiping off the one way vacuum breather on the dashpot assembly i noticed something odd. it is stamped as TEQ on one side but clearly says made in USA on the other. i didnt feel that this warranted its own post but i thought it was weird enough to share. anyone have any insight?

 

It's possession, call a priest!

Your idle signal is good? (You say you followed the book, but some people have lots of problems with this since it can require a few extra hands.)

With just a bit of throttle plate movement before it sends the off idle signal? (If it's too tight it will fluctuate)

How well does the sensor seat, how did the enclosed end of the throttle body valves shaft seat look (that's a mouthful)..

Get it up to full operating temp, set the idle, check the timing, reset the idle speed again if needed, then another check on your timing.. Remember these are interlinked changing one will cause the other to shift to some degree untill the "window" is small enough you can't notice or are tired of tweaking them and call it good enough.

You did change the sensor with the throttle body in place right, otherwise you have a ton of variables you need to eliminate.

Such as.
idle valve, plumbing and electrical.
Throttle body gaskets.
Throttle cable tension.
Random things you might of incidentally touched.

Bottom line is you should have probably left the idle screw alone and waited for it to settle. It seems like you're just chasing it around..

 

lots of questions, ill see if i can answer them all ha.

i removed the throttle body, as far as i could see there is no way to remove the tps without removing the throttle body. new gasket. vac lines are good. i just went and checked and the throttle cable has a little slop in it, i may try snugging it up. i have not checked timing yet as my gun is with a buddy for the weekend, will get at it this week. what do you mean by electrical to the idle valve? the only electrical that was touched was the plug on the TPS. i guess i failed to see how changing the TPS would have affected timing. i did have to adjust the throttle stop screw, although in hind sight i dont think i really needed to i was just following the procedure. also i believe the stop screw to be pretty damn close if not exactly where it was to begin with. i also cleaned the hell out of the body and butterfly.

 

TB cleaning can be a bad thing believe it or not, if there was grungy bits in the shaftway that aren't there any more it can "suddenly" develop a leak around the shaft. (Throttle body wear is pretty common after 30 years. There really isn't any good reason to do a vigorous cleaning on these, wipe off the plate maybe squirt some cleaner thru the idle air passage and call it good.)

I always have to dig for that stop screw procedure, it should only need done if you have disassembled the linkage which there is zero need to-do commonly, run the screw in until it contacts the throttle stop add one quarter turn and verify throttle plate position is closed with less than a one mm gap.. (?)

Verifying timing and doing the idle screw adjustment as I detailed are linked, every time you change one you need to verify the other.. You moved the idle air screw! (Also good measure to verify the IDLe signal is set correctly as the flash code will indicate the throttle sensor isn't closed. There is a code that's set if you move the throttle off idle or turn on the AC while diagnostics mode is jumpered)

The first gen iacv uses an electronic heater controlled by the ECU. This electrical heating causes the bimetal valve to open and close. (Definitely something you may have bumped into while pulling off the TB. This valve is much more susceptible to gunk that the throttle body air bypass since it is supposed to move.)

There is a procedure and spec for cable slack, but slack is better than not slack. (So probably not that.)

I'd lean most towards the IDLe signal and timing, then the throttle body wear.

 

i counted by quarter turns when I adjusted my idle screw and set it back to where it was originally. Ill get at timing this week. Thanks for the help.