TPS sensor problems

[Sleeper-6]

Tonight I was doing my "spring cleaning", yeah i know it's September, but anyway I set the IAC counts with the scanmaster so they sit at about 22. No prob there. I ran into some trouble with the TPS, I can get the idle setting no prob. When I try to adjust for the WOT throtle setting, The best I can do is 3.38 or so. I tried pushing it all the way down with my finger just to see what would happen, and 3.68 is all she's got with the arm bottomed against the TB. I coulden't get it to read any higher. What gives ? Is it sensor replacement time? Thanks.

 

[TurboDave]

Basically, forward movement of the whole sensor is what gives you your highest WOT TPS, and then moving the nose of the sensor up or down (Very slightly) will get your idle values where you need them. But move the whole sensor forward as far as it will go and see what you get fo r WOT settings.

 

[bruce]

Originally posted by Sleeper-6
Tonight I was doing my "spring cleaning", yeah i know it's September, but anyway I set the IAC counts with the scanmaster so they sit at about 22. No prob there. I ran into some trouble with the TPS, I can get the idle setting no prob. When I try to adjust for the WOT throtle setting, The best I can do is 3.38 or so. I tried pushing it all the way down with my finger just to see what would happen, and 3.68 is all she's got with the arm bottomed against the TB. I coulden't get it to read any higher. What gives ? Is it sensor replacement time? Thanks.

Look to make sure the carpeting isn't wadded up behind the pedal and the linkage is fully opening, against the stop.
3.68 while on the low side will still get you into PE, properly. The ecm doesn't care about the max TPS you can reach, it just cares that you hit the enable threshold.
While there is an exception to the above, I seem to be the only one doing it.

 

[Sleeper-6]

I've tried every position of the sensor on the TB but I cant seem to get enough out of it. Even with a friend holding the pedal to the floor, the throttle plate is wide open, if I push the little arm on the sensor all the way down there just isn't enough throw to make the right amount of voltage. Also, Sometimes when the car is cold, but in closed loop, the engine will momentarily cut out for a split second right around 2000 RPM, but runs great above or below 2000. Problem goes away when up to full temp. Could this be related?

 

[Sleeper-6]

ttt

 

[Mr. T-Type]

I used a multimeter to do mine. You may have to make the slots a little bigger to provide more movement. Best I could get with mine was 0.8@idle and 4.6@WOT without making the slots larger.

I did it with the car off and moving the throttle plate with my hand to make sure it was truely WOT.

 

[U1ARUNIT]

I drilled the bolt holes out larger and pushed the sensor forward when setting it and I have .42v idle and 4.68v WOT.

 

[NJTurbo]

Before you go drilling out holes, check the reference wire coming out ECM going to TPS, see if you have 5 volts coming out ecm wire going to TPS.

 

[Sleeper-6]

Thanks guys, I assume that's the center wire on the connector. I've got 5.02 volts there. So i guess that means that the wiring and the ECM are good up until that point. Now what? Can some one tell me what the resistence is on a good TPS is over it's sweep, and between what terminals. Maybe i can check mine with the meter before i go changing stuff.

 

[Dan Thompson]

I believe that the TPS is just a variable resistor between 5 volts and ground.

You might just take it off and see if you can get the voltage to read in the high 4 volt range.

I was in the same spot once and I kept adjusting and adjusting and finally I got the floor mat out of the way and I noticed it made a difference where I had my foot on the peddle.

Anyway I finally got it adjust and I got a code, 21? or 22?, of voltage TOO high. This without drilling out any holes.

I have a spare TPS around here if you need one.

 

[Sleeper-6]

Well, that's what I'm trying to figure out. It seems like the TPS resistence is too high to attrain the max reading I need. But I want to know what the resistence is on a known good TPS before I go buying replacement parts I don't need.

 

[Steve Wood]

Make sure the tv cable is not so tight that the throttle blade cannot open all the way which in turn limits the movement of the tps arm. If you removed the sensor to move the arm, then ignore the above.

It is nice to have over 4.0 volts showing at wot because this is the factory point required to turn off the ac compressor. I don't know if some aftermarket chip makers change this point or not.

 

[gofstbuick]

I too just adjusted my IAC and TPS. I was wondering if it is best to set the TPS (at idle) at the lower range (0.42v) or higher range (0.46), and why?

 

[Steve Wood]

It makes no difference as the ecm scales the voltage each time you start the car. On the other hand, if it reads above .46 at idle, it can screw things up so it is safer to set it a bit lower to avoid that possibility. Performancewise, it makes no difference if it is set at .38 or .44.....but one should not exceed .46 as the computer then thinks something else is going on other than normal idle and you can end up with an idle that is much higher than commanded.

 

[gofstbuick]

Thanks Steve.