TPS problems

[Matsumoto]

I was having troubles with idle in my SS. The throttle body that was on there when I bought it was painted black and the stop screw on the top looked like it was messed with. So I swap out throttle bodies and now the throttle is acting crazy. When you touch the gas it shoots up to like 4k and stays there and VERY slowly returns back to around 1k. I tried the idle switch calibration but was receiving nothing from the 1 and 2 pins. I then check the resistance on the TPS itself (pins 2 and 3?) and it says 9.7 instead of the 12 that the service manual states. Also, when we tested the resistance when the throttle moves from closed to open, it starts at 9.xx and moves down instead of up.

I did search and found a thread that was talking about the 90-91 TPS having backwards readings. The car itself is a 93 but it has had a another EJ22T installed, possibly from a 90-91.

I need to know if the 92+ models have a different TPS than the 90-91 and if this would casue a weird idle and throttle control without throwing a code.

I know this post is super confusing but I just wanted to dump as much info from the top of my head. Any info would be greatly appreciated. Thanks!

[Legacy777]

All the 90-94 TPS's are the same. turbo or non-turbo.

Are you sure you got the right pins when you were testing?

Maybe the TPS on that TB is bad.

I'd also suggest resetting the ECU if you swapped TB's.

[Matsumoto]

I'm sure we tested the right pins. I also tried the TPS from the old TB and it had the same readings. I guess it's possible that both are bad. What's does one of those run from the stealership?

We also broke the plastic PCV connector between the valve covers so I can't really test much until that comes in. So frustrating.

[tris91ricer]

I had a similar problem --goes up to about 4 and stays there until it decides to drop back. Pretty dangerous at 40mph and you're trying not to rear-end someone.
Here, this from www.1stsubaruparts.com:

THROTTLE POSITION SENSOR, Legacy 90-94 $325.15(cost) $234.11 (you pay)
So about 250 bucks, sir.
Fuck me, that's expensive. I might need a new one, too. Goddamnit.

[professor]

it seems hard to believe that both TPS would be wrong in the same manner.

I think it would be far better and more accurate to test the voltage coming back to the ECU from the TPS as mounted in the car, rather than looking at the resistance (0-5V backwards approximately).

The difference between 10k ohm and 12k ohm is not that big and the returned voltage would be very similar (the ECU would see: "the throttle is pretty damn close to wide open"). Not only that but others report that the max. resistance they atually see in use is around 10k so that may not be a problem at all.

are you sure you don't have mechanical issues with the throttle cable or springs, pedals etc ?

[Kelly]

TPS problems:

Did ja get the memo?

[Matsumoto]

TPS problems:

Did ja get the memo?

Ha! I feel like I'm in the club now


Ouch! These things are pricey.

I will definitely try and measure the voltage coming back to the ECU. Thanks for the advice. The only reason I don't think it's mechanical is that when I try and close it more by hand the idle isn't affected at all. So it seems that the throttle plate is fully closed. Even so, I am going to look a little more for a mechanical failure as well.