TPS - huh?!?!?

Landshark · #1 03-15-2003, 03:46 PM

after getting some goofy readings doing Trevors "pin-in-the-wire" method of adjusting the TPS by voltage, i finally just took it off and decided to check the resistance. from a Beav post i had archived, it should have read 10-12k ohms closed, 3-5k ohms fully open (or vice-versa.)
mine was reading 5k ohms closed, 400 ohms fully open.

don't tell me '97's have special TPS's! car runs OK, just some weirdness at high rpms. according to the readings i'm getting, it shouldn't run anywhere near normal!
thanks for any help........

CDG · #2 03-15-2003, 04:33 PM

I wouldn't worry about the actual values, what you are looking for is spikes of open connections, the TPS should be turned very slowly, watch to see if the ohmeter drops/rises to infinite resistance(open cct) during the movement. That will show dead spots. Now lets hear from others who have tested their SVX TPSs, as I have only tested countless other TPS type sensors in other cars, so I'm not sure if the TCU is supersensative to these or not.

If you get a very smooth change in resistance, try speeding up the motion.

Let us know what you see.

Landshark · #3 03-15-2003, 04:39 PM

i just want to get it adjusted properly - i took it off for cleaning a while back, and lost my pencil mark for re-alignment (yeah, shoulda scribed a mark!). ever since, at high rpms, which i don't hit too often, it acts funny. i just need to get it set properly so i can relax.

Trevor · #4 03-16-2003, 03:24 AM

Taking a voltage reading as instructed in the Subaru manual is the only way to properly set the TPS. By using the method I have suggested it can be done wth very little hastle. If you are doing exactly as I suggested and are getting "goofy" readings ( what exactly do you mean ? ) something is wrong.

The element should measure a fixed 5000 ohms across the element in accordance with details which I also posted. You will not measure zero resistance with the wiper fully one way or the other and 500 ohms is about the same as mine. Not sure what you mean by closed and open. In no way should any reading exceed approx. 5000 qhms. If it does and you are sure you have made good connections and the reading is accurate, this would indicate that the unit is faulty.

There is nothing unusual or "super sensitive" about it and the points made by CDG are relevent. The resistance change should be smooth and most definitely even and constant. However in actual fact the resistance will change in very small increments, each equal to one turn of the resistance wire wound on the element former, but this will not show when using an ordinary ohm meter.

N.B. Read fully the post a day or two back -- Cleaning the TPS by Stevesby.