TPS cleaning tips?

[svx_commuter]

Originally Posted by floatingkiwi

Ahhh, if you do that you'll be changing the resistance and then it won't operate correctly (the ECU will be seeing a different idling voltage). I'm not sure if it would adjust to this over time but from other posts and a bit of contemplation I would say not.

Matt

I have done this and it works. Just reset the ECU by pulling the neg of the battery or the fuse, let it sit aleast 5 minutes and then start it up. After a few restarts everything is fine, idle is right back where it's supposed to be. This si part of the learning circuit. I also found another way which works faster but wastes more gas. Pull the neg off for few hours and then reconnect and start the engine but don't touch throttle. Let it idle for 20minutes until is warm and then shut it off and let it cool down for a few hours.

[svx_commuter]

Originally Posted by floatingkiwi

Mine does something similar but not as bad as yours.
When I'm travelling steady in 3rd or 4th above about 80KM/H, if I very very slightly relax the pedal the revs drop off about 800rpm (and the car feels like it's freewheeling a bit), then if I completely release the pedal (or relax it more) the rpms come back up again and the car starts to engine brake properly i.e the rpms are back in sync with the speed again. There is a little decelerating jerk when this happens as if the 'box is not quite in sync with the engine until I completely release my foot.
It's quite disconcerting when you're driving along straight roads at these speeds, continually adjusting the throttle!
Would this sound like the TPS? incidentally it's been adjusted properly but NOT cleaned. (I'm not in NZ at the moment)

Matt

I think this is the TC locking and unlocking.

[floatingkiwi]

Originally Posted by svx_commuter

I have done this and it works. Just reset the ECU by pulling the neg of the battery or the fuse, let it sit aleast 5 minutes and then start it up. After a few restarts everything is fine, idle is right back where it's supposed to be. This si part of the learning circuit. I also found another way which works faster but wastes more gas. Pull the neg off for few hours and then reconnect and start the engine but don't touch throttle. Let it idle for 20minutes until is warm and then shut it off and let it cool down for a few hours.

I was wondering about that actually. That's pretty neat then - so the ECU adjusts to the different voltage that it is seeing then?
Wouldn't it throw a code? or is it the ecu reset that tells it that it's not really sure what's going on yet and so doesn't throw a code unless it cannot fix the problem? (Errm, that's not a very technically orientated sentence is it ).

Then in this case why do we bother adjusting the TPS to get the idling voltage right?

Regarding: TC locking/unlocking;

My mothers SVX doesn't seem to do this though - do you know what controls the locking or not of the TC? (I suspect you're right though).
Solenoid actuation pressure in the 'box too low?

Cheers man

Matt

[floatingkiwi]

Originally Posted by svx_commuter

I have done this and it works. Just reset the ECU by pulling the neg of the battery or the fuse, let it sit aleast 5 minutes and then start it up. After a few restarts everything is fine, idle is right back where it's supposed to be. This si part of the learning circuit. I also found another way which works faster but wastes more gas. Pull the neg off for few hours and then reconnect and start the engine but don't touch throttle. Let it idle for 20minutes until is warm and then shut it off and let it cool down for a few hours.

Incidentally on another note:

Whenever I store my car when I'm overseas, I always disconnect the battery of course (so the ECU completely loses all "learned tuning"). But when I get home the car goes like a bloody rocket for the first few days and then seems to cool down a bit - funnily enough the fuel consumption only takes a slight dip. Wish I could figure out why this is...

Matt

[dcarrb]

Originally Posted by svx_commuter

I think it is also possible to adjust it out of the worn zone since this most likely close to the idle position.

I wondered about that. Obviously, the installation is designed for adjustment. Mine was pretty much in the center, and I scribed match-marks to ensure that I got it back into the same position.

To update, cleaning the TPS apparently corrected my odd downshift problem. Hasn't happened once in 30+ miles, and I've tried repeatedly to recreate the constant throttle/light load condition that caused the misbehavior. So, on to the next thing.

To anyone giving thought to doing this, there's nothing to it; the hardest part is pulling loose the stubborn breather hose to access the sensor. As someone mentioned, an "office duster" air can comes in handy. There's a small hole inside the socket that's perfectly sized for blowing excess solvent back out of the unit.

Subaru gets $200+ for this part?! It's a Bakelite snuff can with a toylike coil spring and plastic sewing machine bobbin inside. Must be some wildly exotic alloy in those electrical contacts.

Thanks to all.

dcb

[svx_commuter]

Originally Posted by floatingkiwi

I was wondering about that actually. That's pretty neat then - so the ECU adjusts to the different voltage that it is seeing then?
Wouldn't it throw a code? or is it the ecu reset that tells it that it's not really sure what's going on yet and so doesn't throw a code unless it cannot fix the problem? (Errm, that's not a very technically orientated sentence is it ).

Then in this case why do we bother adjusting the TPS to get the idling voltage right?

Regarding: TC locking/unlocking;

My mothers SVX doesn't seem to do this though - do you know what controls the locking or not of the TC? (I suspect you're right though).
Solenoid actuation pressure in the 'box too low?

Cheers man

Matt

Well if it was at 1/2 volt when it came out and then went back in 1/2 volt the ECU would not have to adjust for and change. The adjustment takes some time, a few heat up and cool downs.

The TC lock-up can depend on the how the throttle is used and the load on the engine. A quick tap on the throttle will bring it out of lock-up. Going up a hill will bring it out. Taking the foot off the gas will bring the TC out too. All of this while cruising 50mph or so.

If you haven't tried to reset the TCU, give it a go.

Is there a lot of play in drive train? After the SVX is warm-up just with the ebrake applied so the SVX doesn't move and shift from D to R and listen for banging noises. U-joints? CV joints?

I can always feel some drive train backlash when I take my foot off the gas and then reapply. Along with this a slight jerking motion.

[Archer999]

Hey if you can take a picture of the TPS. I would like to clean mine but I dont have a clue of what it looks like or where it is.

[Archer999]

Nevermind I saw the pics on the how-to-documents.