TPS, what a difference a fraction of an inch makes!

[Guest Legacy777]

pagan you're right, when they don't touch, that is infinite ohms.

[Guest Max Power]

If I am reading my Haynes manual correctly, the procedure outlined above is to be used 'on 1994 models and earlier' which have a 4 terminal harness. Has the procedure been tested on a 1995 or newer (3-terminal) Sube? The instructions for testing '95 or newer are quite different, and do not offer an actual adjustment procedure.

 

I'm very interested in testing the TPS and want to make certain I use the correct method.

 

max

[Guest PaganQWA]

Ok I spent about 3 hours today cleaning the IAC out, cleaning out all air intake hoses and testing the TPS.

 

None of my readings matched what Chiltons listed. All were below except for the Voltage test on terminal 2 (positive wire on plug going to TPS) and it was .09 over the 5 volit suggestion.

 

All resistance tests came up short on the actual TPS terminals but I didnt test resistances from pl ug to TPS. By the time I got to those tests I could crearly see nothing was adding up

 

I wonder though, is the actual TPS broke, harness, or the ECU? Since re adings from the harness plug terminals were wrong would that mean the ECU is sending the wrong amount of volts? Am I maybe getting bad readings becuase the TPS needs to be adjusted?

 

Thanks

[Guest Legacy777]

Pagan,

 

I pretty much got same results you did. Readings that were not really close to what the manual states. I tried setting it near the manual and I got check engine light. I'm really wondering if my TPS is crappy because the car just will not downshift when I dump it. it takes a couple secs. The car's almost always behind what I want it to do. I don't know if this is TPS or crappy trans, or possibly the bogggin intake thing. It's just getting anoying....and now that I'm driving it all the time again....I must have perfection...hahaha.....well something close to that will do.

[Guest CipeR]

I also did not get readings near what it was supposed to be.

 

I think it is more important that you get a good transition from closed to open in relation to total resisitance.

 

If you measure the two correct leads you get the maximum resistance available. Then you measure from one of those leads to the lead that the computer gets a reading from. The change in resistance should be completly smooth, with no spikes either up or down.

 

The same thing was true on my Supra. The Hanes/chiltons were never right.

[Guest PaganQWA]

When I moved the throttle open and close I got no changes in readings really.

[Guest Legacy777]

ummmm.....you're either on the wrong wire...which is most likely the case, or your tps is fubared.

[Guest CipeR]

I agree. One of the 6 combinations of leads should change resistance as you move the sensor. This is the connection the computer uses to measure the Position. There are really three important connections in regards to testing the tps

 

1. On one lead the resistance should change as you move the sensor. I cant remember exactly the numbers but it should be from say 3 ohms at one end and 15 at the other?

 

2. Another set of leads should be the same resistance no matter where the sensor is

 

3. A third set of leads should read no connection at one end (first 10% of range) and directly connected with little resistance at the rest (90% of the range).

[Guest Legacy777]

you gotta be on the wrong terminals. You sure you got the right terminals?

[Guest PaganQWA]

I'll tinker some more on my lunch break, thanks guys

[Guest Itzik93]

my impreza 1994 1.6 has a 3 wire TPS.

 

According to what i found about this, the 3rd wire should post values of 0.2-1.0 Volts on IDLE when engine warmed up.

 

Look at this:

 

I hope this helped some1.

 

Itzik

[Guest CipeR]

Can you post the other side, this is just testing the output to the TPS not the tps itself.

[Guest wrxsubaru]

sorry but i want to know what is tps

[Guest SmashPDX]

Throttle Position Sensor.

[Guest Itzik93]

Not correct !

 

The Diagram Shows you the OUTPUT Signal from the TPS....the INPUT is 5V (red wire).

 

Meaning: the output should be 0.2 - 1.0 Volt On Idle (Fully Closed) and 4.2 - 4.7 Volts when the throttle is Fully Opened.

 

Itzik

[Guest wrxsubaru]

thanks

[Guest CipeR]

Itzik93:

Who are you saying not correct to?

[Guest SmashPDX]

Is this thread ready to be archived?

[Guest Itzik93]

Im saying "Not correct" to you - CipeR.

 

The values that you see in the file attachment from my previous message(s) are equals to the values that the TPS should give you as an OUTPUT to the ECU.

as i said before: 0.2-1.0V in full closed throttle (signal wire)

and 1.0 to 4.7V in full OPEN throttle.

 

If you have a 3 wire TPS, check it and see by urself.

 

Itzik

[Guest PaganQWA]

Anyone got a spec sheet like that for us 4 wire TPS users? (EJ22)

[Guest Legacy777]

you lookin for something like this?

 

http://usmb.ultimatesubaru.org/forum/showthread.php?s=&threadid=2512

[Guest PaganQWA]

I already have a crappy Haynes

[Guest truk]

Well, after all this talk, I decided to check out the tps on my 96 OB wagon. Instead of doing the backprobe thing, I unscrewed the whole job and took it off to see the inerds. The part that actually touched the throttle was a little dusty, so I cleaned it off. After putting it back on in the same spot, the friggin' CHECK ENGINE light came on. I drove it around and all is fine. Little adjustments with the screws almost tight didn't get rid of the light. Any ideas?

[Guest Legacy777]

How did you take apart the TPS?

 

I believe the casing is riveted together.

[Guest PaganQWA]

It's prolly maladjusted... did you re-adjust it properly after putting it back on?