adamthedroog

Hey all

I'm a little confused about adjusting the throttle position sensor. When I hook up my ohmmeter to one pair of terminals and adjust it will that make the others adjust right too?

thook

The "others" don't adjust. You're testing them for resistance to know whether or not those circuits will carry a correct voltage signal. If there's too little or too much resistance or none at all, the voltage signal will consequently be incorrect (too high, too low, or none at all) and the ECU will detect the throttle plate position incorrectly.

When you're adjusting the throttle sensor, you're setting it to where the ECU will detect the static idle position of the throttle valve/plate. This is the IDL - E2 circuit; IDL terminal being for voltage signal and E2 being the ground. Like any electrical circuit, voltage has to have a ground so the circuit will be complete and voltage can travel.

So, to put it in simple terms, think of it like a contact switch; throttle closed = "IDL" switch is "ON" so far as how the ECU sees it. Throttle open = "IDL" is "OFF". You're merely setting the sensor in the exact spot where the switch contacts will turn on or off in direct accordance with the actual idle position of the throttle plate.

Once the throttle opens, and IDL is off, the ECU then takes throttle position readings from the VTA or "throttle angle" circuit. The signal from VTA tells how far open the throttle is. The other two circuits are VC for voltage supply to the sensor and E2 for voltage ground. Again, none of these have an adjustment. There's no need. Just make sure the resistance is correct once the IDL-E2 adjustment is made.

Hope that helps clear the brain circuits for ya..... If not, and if you want, I'll try again.

adamthedroog

That helps. The only thing I'm still confused about is that in the service manual it says to insert a thickness gauge between throttle stop screw and stop lever then measure the ohms. Then it says if it's wrong unscrew the position sensor and turn it.

MudHippy

That's correct. If it's not within those specs then it needs adjusted. So what's the part that's confusing you?
http://personal.utulsa.edu/~nathan-b...93throttle.pdf

Guardian_Saint

If you find it hard. May be a quick fix but I would check afterward. My truck have issue with missfiring before so I follow one of the member here about the sensor and all he said is to let your engine idle then open up the sensor from its two four head screw. Not all the way out and move it down or when you hear the engine idle very high than move it slowly back, and when you hear the idle drop. Stop there and screw them back in. I don't know if it is the correct method but It has work out for me so far...

thook

It's not a procedure given in the manual, but you're not setting it in a way that's any different than using the feeler gauges. You're simply setting to where the sensor "turns ON"......contact switch/circuit is closed.... when it detects the idle position of the throttle plate. The drop in idle means the ECU is then getting that signal from the throttle sensor. The high idle means the ECU is getting no voltage signal on that circuit...the IDL circuit is open.

It might help to run a google on open and closed circuits to understand that a bit better, for anyone not understanding this.

coops2k

I might try this on my 22RE, since I have the TPS adjusted by the book, but I am still getting some jerking in the drive train, when letting off the gas or putting my foot back on the gas. The new TPS took care of 85% of the problem, but it is still there a little.

thook

^^^^ That sounds like it might be a u-joint seizing, dude.

coops2k

we looked at them, they seemed ok

alltracman78

Looking doesn't always tell you.
Sometimes you have to take the prop shaft off and see if they move smoothly.

thook

^^^^ This!

Really, you gotta pull the shaft down and move it by hand. On the vehicle, it can look solid w/grease and feel solid, but there's tension on it. The needle bearings could be toast and you'd have no idea until you pull it down.

coops2k

OK, THANKS guys, that is why I love this forum, good people and information. I will do that or get it done in the near future. In the process of moving

92dlxman

thook has you going in a great direction as he has a way of doing.

to try and add, your looking for a rather wide resistance range at your idl/e2 check. the trick is to set it and have all other readings within their specified ranges. in my case i did actually have to get pretty precise and say some bad words to obtain this.

so moral of the story is do all checks stated in the manual. they are all important. your idl circuit, and vta's to determine correct resistance at pre-determined throttle openings. take your time. you'll get it

jdamore

I just purchased a new TPS. and I'm trying to get it adjustted now.. however i'm having a real tough time getting my guages between the lever adn stop screw on my 3vze.. any one have any tips? :/ its hard to make out on the Drawings.. but i can't seem to get the right angle

Ben Floyd

Im working on a friends 94 3.0 4runner. We determined that the TPS was bad. I installed a new OEM part and am having trouble getting it adjusted properly. It will only go down to about 4.8 before the meter drops off. I see that it calls for 2.3k or less. Any tips? Not sure what is going on...thanks!

scope103

Drops off the bench? Off the fender? Just what do you mean with "the meter drops off"?

All you're trying to do is to make sure the contacts "close" at idle. Since there will inevitably be some resistance (less so if you squeeze the contacts), Toyota says "yeah, anything under 2.3k ohms is good enough to call closed."

Ben Floyd

Basically as I'm turning the tps, that's as low as the meter gets when the TPS runs out of adjustment. Then the screen on the meter goes blank, like it's "dropping off". I just didn't have a better way of describing it.

scope103

When you are measuring ohms, zero is always the "lowest" the meter can go (which you should get, or very close to, when you short the leads together). The "highest" the meter can go depends on your range setting. If you have a common 3 1/2 digit ohmmeter, and set it to the 20K ohm range (for instance), once you get MORE than 19.99 Kohms it goes to over-range. The most common indication of that is 0L (overload?), but it depends on what your meter does. Of course, with the meter leads connected to nothing, you nominally get "infinite" resistance, which is more than 19.99K, so you should always get the over-range indication, independent of range.

The only time I've ever seen a digit meter screen go blank is when the battery is depleted.

Ben Floyd

I'll try some fresh batteries. With that being said, if im only getting 4.8 on the 20 kohm setting and the very bottom of its adjustment, whats my next step?