TPS adjustment

[bentonrover]

So on my 90 FJ62 a code 51 came up. Throttle position sensor. The rig was giving me idle surges every so often. Its not my daily so I just ran it. Decided to clean the throttle body and replace the sensor. I took the throttle body off and replace tps per fsm. My opinion the book dont say much. So when applying do the tabs line up? Meaning the throttle body tabs slide into the sensor and slightly have the tb plate open? Or do the tabs from the throttle body rest on the back of the sensor slots with the throttle plate closed? Confused caused once ligned up its at a high idle over 2000 rpms. Trying to adjust but cant figure it out. Took a break cause my patience is done tonight. Any links? I have a meter and fsm and Im clearly doing it wrong. Thanks

 

[lechnito]

I just started getting code 51 again so I'm coincidentally recalibrating my TPS today. The part of the FSM that best describes the TPS diagnostic procedures are FI-64 through FI-66 in 3FE REPAIR MANUAL.PDF

When the throttle linkage moves, it pushes against the tabs inside the TPS which incrementally changes the resistance of the internal circuit. The accompanying change in voltage is then used by the ECU to determine throttle position. For this to work correctly, the TPS tabs need to have the correct preload tension against the throttle linkage which is then secured in place by the two phillips screws on the TPS.

 

[bentonrover]

Thanks for the reply. When I place the tps correctly on with tension is the throttle plate open slightly or should it be completely closed?

 

[lechnito]

It's the TPS that should be rotated into position not the throttle plate. The throttle plate only opens when the accelerator cable is pulled when you push down the throttle pedal. In other words, the plate should be closed when the TPS gets secured.

I just pulled my TB and TPS out. I'll post some photos of the calibration steps in a bit...

 

[bentonrover]

So grateful thanks.

 

[lechnito]

I had to run out and buy some new screws for the TPS. The head on one of my screws was way too damaged to use again. For the record, if you ever need to replace these screws, they are Pan Head Machine Screws M4 - 0.70 x 12mm

To calibrate the TPS, you'll need a multimeter and some feeler gauges. Put the TPS back on the TB and tighten down the screws so the TPS is held in place but can still be rotated freely. When you rotate the TPS, make sure the throttle plate is not opening also.

Set the multimeter to measure 2k ohms and hook the clips up to the IDL and E2 prongs:

Next, find the combination of feeler gauges that most closely adds up to 0.93mm (I was only able to get to 0.915 but that should be close enough.) Put the feeler gauges between the stop screw and butterfly valve as shown below. You do NOT want to put the gauges in front of the dashpot!

Be sure not to let your alligator clips touch each other (meter will read zero) or the other prongs.

Turn the TPS counter clockwise all the way and your multimeter should read somewhere between 0.01 and 0.03. Now verrrrrry slowly rotate the TPS clockwise until your multimeter deflects (for me, it shows 1). The line between correct and too much is incredibly fine here so be patient and slow. Once you've hit the right spot, use one hand to hold the TPS in place and the other to tighten down the two TPS screws to secure everything in place.

When you remove the feelers, your meter should go back to reading between 0.01 and 0.03. When you turn the butterfly valve, you should see the multimeter spike back up to deflection.

Now go reinstall your throttle body and don't touch the TPS screws again

EDIT: The first picture I took shows the TPS having been installed backward. I just re-calibrated the thing with the TPS oriented correctly and updated the photo. Let's just forget that happened...

 

[bentonrover]

Thanks for the reply. The main issue is how to get this simple tps on this throttle body without leaving a gap...lol
When I line up the tabs from the throttle body to the slots on the tps I have to rotate it to align the screw holes. Which leaves a gap. I love this truck for the basic simplicity of it. Id rather do a knuckle job then this adjustment. Hint if you in CT and need front hub rebuilt come do this for me for a trade.

 

[lechnito]

What do you mean? Where are you seeing the gap?

If the throttle plate moves when you rotate the TPS, you don't have it installed correctly. The TPS tabs should be moved by the TB tabs not the other way around.

You might be overthinking it

 

[bentonrover]

Thanks I think I have it now. Appreciate it. Never again lol

 

[ryanCA]

Thanks I think I have it now. Appreciate it. Never again lol

View attachment 1545984

The yellow screw you have - if you turn it - is that what raises the idle ?

 

[RodrigzCrzr]

The yellow screw you have - if you turn it - is that what raises the idle ?

No that is one of two screws to loosen the TPS.

 

[bentonrover]

The yellow screw you have - if you turn it - is that what raises the idle ?

No sorry that's the fastening and adjustment screws. After I got it all aligned I made the mark with a paint pen to where it should be and stay is all

 

[ryanCA]

Thanks guys. The large screw over that yellow mark to the right - seems to make adjustment on idle ok.

 

[bentonrover]

Thanks guys. The large screw over that yellow mark to the right - seems to make adjustment on idle ok.

Lol oh ok that one.