I have an 89 4runner 3.0 5speed and I just replace a bad TPS to fix one problem and now have a new one where the truck gets jerky when going from a coast back to accelerating. The TPS seems to be adjusted properly… 200-800 ohms is the spec and I am at 684 ohms… Idle is 800rpm and timing is right on. Should I aim for the lower number or the higher when adjusting it to the firs spec? I don’t really understand what the TPS is doing with it’s resistance but maybe I need to adjust it differently. The adjustment meets the other requirements.

On a carbed 22r there is a gas cut off thing that regulates fuel when coasting does the EFI have something like it that may be bad? I didn’t have this symptom before changing the TPS… so I believe its related gurus please reply.

Thanks

 

Your IDL contact on you TPS is not closing on throttle release. With the throttle closed you should have very low resistance, if an (I think spec is anything less then 120 ohms), across the IDL-E2 pin on the TPS. As soon as the throttle starts to open that resistance should jump to infinity. It is just a switch to tell the ECU that the throttle is closed. This controls timing and a bunch of things.

You can test it by checking with a meter or just short your diagnostic terminals under the hood and you should here the engine drop. If the engine does not drop then that switch is not closed.

 

The first test says 0-.50mm = 200-800ohms
The throttle stop is a 0mm and If i crank the TPS as far down (Counter clockwise) I still get a resistance of 372ohms at 0mm. At .77mm I haven't reached zero resistance yet. Resistance between IDL and E2 is 164ohms.

How do I measure IDL is that right?

This is the chart I'm using but I don't understand if these are ranges... it says they are alternate chart specs.

Table 2: 3VZ-E (3.0 V6) - TPS Adjustment Specifications
(*) Some test charts list these alternate throttle openings for testing Test Clearance between
lever and stop screw Between terminals Resistance /
'88 (ohms) Resistance /
'89-'95 (ohms)

1. 0.00mm (0.000")
or 0.50mm* VTA - E2 200-800 200-800

2. 0.50mm (0.020")
or 0.77mm* IDL - E2 < 2.3K < 2.3K

3. 0.77mm (0.030")
or 0.85mm* IDL - E2 Open / Infinite Open / Infinite

4. Wide Open Throttle VTA - E2 3.3K-10K 3.3K-10K

5. n / a Vcc - E2 3.0K - 7.0K 4.0K - 9.0K

 

If your IDL-E2 is 164 then you are good. The rest of the measurments should not effect this problem that you are having. As long as the VTA-E2 steadly climbs as the throttle is opening then it is fine.
Also check your dashpot. It is the thing that slows the throttle plate down just before closing. It is by the throttle stop. It is like a little air plunger that is spring loaded out. It should hit a screw on the throttle just a bit before bottoming out. This is so that when you let off the gas the plate does not slam close.

 

Thanks Flash

It's set... The dashpot makes contact just before the stop position. It's not much though. when I operate the throttle by hand initially it seems to stick.

I'm going for a test drive...

 

I'm having this same issue, but you guys have totally lost me. Which part of the FSM should I review?

 

Ok.. a better discription is one jerk as you get back into the gas after a coast at low RPM's. My last TPS was worn out and didn't return all the time. More help please

Thanks so far.

 

The part about the Throttle body shows how to test the TPS. The dashpot may be there as well.

 

http://www.4crawler.com/4x4/CheapTri....shtml#Dashpot

 

Thanks for the help - another little thing to check and tweak for me - too much fun

 

Check the dash pot information on the web page above. I found on my '85/22RE that I needed to adjust the DP so that the plunger went in about 1/2 of it's travel. That way the little spring tension in that plunger would help smoothly open the throttle off of idle. With too little plunger contact, the throttle would tend to stick closed and then release and open all of a sudden. With too much plunger contact, the throttle would not always close fully. And check the little air filter and check valve on the DP, it is supposed to allow the DP plunger to extend quickly but compress slowly. If the valve or filter is clogged, the plunger won't extend as you open the throttle and thus won't help it open smoothly.

 

So the throttle plate shouldn't close all the way?

The stick was carbon build up... I guess I didn't clean it when I rebuilt the motor... cleaned now and I made sure not to infect the TPS with cleaner.

I'm going to try the highest range on the VTA to E2 800ohms and if that doesn't work I'll adjust the dashpot / throttle plate to be slightly open.

 

Yes the throttle should close fully, stop screw is usually set to make contact with the linkage with the throttle plate closed, then turn the screw in 1/4 turn and lock it in place. But other than that, you need the plate to close to the stop. The DP slows the closing when you let off the gas and as I found it also seems to help it to open smoother off idle. Not sure if the 3.0 linkage is similar, but on my '85, the way the linkage is set up, it is pulling at an off angle near idle so I don't think a lot of the force from the throttle cable gets to the throttle linkage. Once you open it up a little, then it works very smooth.

And yes, have heard about playing with the TPS IDL-E2 setting to vary the off-idle throttle response. Basically, as long as IDL-E2 is under 2300 ohms, the ECU thinks the throttle is closed, once it goes over that value, then the ECU reads the actual throttle position, so if the throttle is open a fair bit before that IDL-E2 reading goes infinite, then you might have a sudden jump in engine output.

 

something probably unrelated-
I've had a few vehicles which would 'jerk' when transitioning from closed throttle to open throttle (like you were coasting in gear up to a traffic light then the light turned green so you just step on the throttle) and it was caused by worn engine mounts. With the mounts worn, or even worse- one broken, the mounts are loaded one way during deceleration and then suddenly shift the other way during acceleration causing a jerk.

 

Earlier I said zero and I guess I meant infinite... anyway, thanks for all the help I'll adjust the daspot first, then play with the TPS one last time and post my results.

 

I think it's fixed. I ignored all the specs accept I set the IDL so that at .85mm of throttle it goes infinite. It might be better if it were at like .75mm when the circutit opens but that would make the other measurments even higher. What's too high? When the throttle is closed I'm at 1200ohms on the VTA and 190ohms on the IDL... I forgot to check VTA at wide open throttle