Adjusted TPS. Better Throttle Response

[landtoy80]

I removed and adjusted the TPS. I was a bit confused with all the Ohms and K Ohms so that I didn't get to do a proper testing of the TPS. I just did the adjustment per the FSM. I put a paint mark on the TPS and had I known that the adjusting is so minor I would of use a fine point marker as I can hardly tell if I turned the TPS at all.

After adjusting, it feels like there is more throttle response, a lot more response. It feels like it takes less throttle to get the 80 moving. I usually push it accelerator way down when driving around town but now have to hold my foot back to keep an equal speed or acceleration. To make sure it was not just a placebo affect, I had the wife drive the 80, telling her I wanted to listen for a noise. She said she felt like there was more power and it was not dogging like it normally does when you push on the accelerator.
My hesitation when reving the motor in N is gone too.

Could an out of adjust TPS make such a difference?

EDIT:
I just found that the trans cable was not hooked up after removing throttle assembly for TPS adjustment. Prior to removing the throttle ass. the trans cable was way out of adjustment. With the cable pulled way out at idle. This made the throttle response feel poor. With the trans cable removed, it must of set the trans to default mode and making the throttle response more responsive.

 

[TexasJack]

I am thinking that you are simply idling at higher RPMs so when you start to accelerate, the engine feels more responsive. Others may know better.

 

[Offroads4x4]

Did you move it clockwise or counter clockwise and how far?

 

[ToyotaDon]

The TPS tells the computer to retard the timing when the IDL circuit is closed. This is what you are adjusting with the feeler gauges and ohmmeter. If it already thinks the throttle is off-idle, it won't make the initial bump in timing advancement. You can see this happen with a properly adjusted & working TPS; with a timing light connected, cracking the throttle will show about 10-15° of advance.

 

[JCruse]

My 80 takes off really well. I can't tip the pedal more than an inch or two unless I want to race off the light. Then it peters out pretty quick. Seems to have a lot of torque down low and excellent throttle response, but it doesn't last.
If I want to keep it going like that past 35-40MPH
I have to pretty much bury the throttle, and listen to that silly whistle.

It's a '97 btw.

 

[landtoy80]

I turned the TPS counter clockwise and it was so minor that its hard to tell with the paint mark I put on it before I loosened up the screws.

It doesn't take much turning to be in spec or out of spec via the feeler gauge adjusting. With my vacuum gauge not holding vacuum I ended up tying the plunger under the set screw under the TPS. It was still a three handed deal to check the ohms, hold the throttle assembly and turn the TPS and tightening the set screws.

The idle is the same rps.

Not 100% but it feels like the foot throttle moves with less pressure. It could be that I just don't have to mash the throttle as much.

I did move the TPS back and forth several times between the screw stops. Not sure if something was bound up in there like dirt or crud and turning it freed it up???

 

[Offroads4x4]

Thanks. I was wondering before I try swapping one out for a friend.

 

[landtoy80]

If you put a paint mark on it before you loosen the set screws, use a very fine point mark on it. I paint marker is just to wide. You are using feeler gauges to adjust.

 

[ToyotaDon]

I did move the TPS back and forth several times between the screw stops. Not sure if something was bound up in there like dirt or crud and turning it freed it up???

That is actually pretty common for them to stick, but sometimes electrical cleaner will free them up.

 

[landtoy80]

Can you take it apart and clean the TPS?
I though about removing it and checking it out but I didn't see thing in the FSM about removing it. Didn't want a spring or something to fly cross the room.

If you just remove it with the 2 bolts, is it contained or will it come apart? I would assume its contained but who knows.

 

[LandCruisinMike]

is the throttle in everyone's smooth? the one i just bought has a tight spot as soon as it tries to move, then another 1/3 to 1/2 throttle. Of course I've got bigger issues i'm dealing with for now.... rattle rattle clang clang....

 

[Polar Bear]

Can you take it apart and clean the TPS?
I though about removing it and checking it out but I didn't see thing in the FSM about removing it. Didn't want a spring or something to fly cross the room.

If you just remove it with the 2 bolts, is it contained or will it come apart? I would assume its contained but who knows.

Its all contained, you can remove it without fear. I replaced my TPS while chasing down a mysterious engine stumble. It had some corrosion inside from deep water crossings (that and I live in a place where moss grows on anything that stops moving for more than 5 minutes).

I was unable to adjust it per the fsm, as I didn't have a vacuum gauge or a clue how to properly do it. Instead I stuck it on the old gluteus dyno and tuned it accordingly. Works pretty well if you don't have the proper tools.

 

[landtoy80]

The only reason for the vacuum gauge is to pull the plunger back that opens the throttle. All you need is a wire or tape to pull the plunger back. Once you have it tied back, you just barely loosen the set screws and tap with you finger or soft tool in either direction till you get continuity for the one feeler gauge and no continuity for the other feeler gauge. Not sure if you can do it without removing the throttle from plenum.
The FSM has you do all this Ohms testing and which can be intimidating if you know nothing about electrical components when all you have to do is set the gap with feeler gauges.

 

[Polar Bear]

The only reason for the vacuum gauge is to pull the plunger back that opens the throttle. All you need is a wire or tape to pull the plunger back.

Ah, this is a piece of knowledge which would have served me well 2 years ago

 

[landtoy80]

Its probably a good idea to replace the steel gasket between the intake and plenum if you remove it to adjust but my gasket is only a year old and doesn't seem to be leaking so far. Will get a new one later when I pull the TPS apart to check for corrosion.

Does it look like putting dielectric grease on it would help with corrosion or would it just attract dust and dirt?

 

[Polar Bear]

It shouldn't need anything if memory serves. Been 2 years though...

 

[landtoy80]

Is it removed by removing the 2 adjusting screws?

 

[Polar Bear]

Is it removed by removing the 2 adjusting screws?

That should be all it takes IIRC.

 

[landtoy80]

I just found that the trans cable was not hooked up after removing throttle assembly for TPS adjustment. Prior to removing the throttle ass. the trans cable was way out of adjustment. With the cable pulled way out at idle. This made the throttle response feel poor. With the trans cable removed, it must of set the trans to default mode and making the throttle response more responsive.

I did remove the TPS and it was clean as a whistle under there. There was nothing under there to fly off or fall out. Its a very simple setup.

 

[jdn1299]

The only reason for the vacuum gauge is to pull the plunger back that opens the throttle. All you need is a wire or tape to pull the plunger back. Once you have it tied back, you just barely loosen the set screws and tap with you finger or soft tool in either direction till you get continuity for the one feeler gauge and no continuity for the other feeler gauge. Not sure if you can do it without removing the throttle from plenum.
The FSM has you do all this Ohms testing and which can be intimidating if you know nothing about electrical components when all you have to do is set the gap with feeler gauges.

I realize this thread is over 10 years old, but I am reading through before I attempt to adjust my TPS.

Where do you attach the wire to pull the plunger back? I can always run to the auto parts store and rent a vacuum, but I'm trying to avoid that.

Thanks!