TPS cleaning tips?

[dcarrb]

My silver throws unforced downshifts out of the blue when the throttle is held constant (I drive it almost exclusively on curvy backroads and only recently noticed this on a long, straight stretch of highway), and I'd like to try cleaning the throttle position sensor. What exactly is there to clean? Does the unit disassemble, and if I take it apart, will I regret doing so? Should I not bother and just go ahead and swap with the teal? There's already a painted match-mark present, but it doesn't appear the sensor has been removed recently. Tips and suggestions appreciated. Thanks.

dcb

[SVXtacy]

I have the same issue, so who wants to answer this? I think mine resulted from trying to clean the engine.

[rbalach]

Try the How-To Documents link at the top of the page

How-To ---> Engine ---> TPS

[dcarrb]

Originally Posted by rbalach

Try the How-To Documents link at the top of the page

How-To ---> Engine ---> TPS

Did that before posting and found nothing there that answers my questions.

dcb

[dwd1985]

The TPS comes off of the throttle body in one piece, and stays in one piece. There are no screws to take it apart, it is one solid part. I am sure that if you attempt to take it apart by force, you will not be able to get it back together. If you are having problems with the shifting, then cleaning it is worth a try, but from my experience, only works about 25% of the time. You might want to try cleaning it, and then if it still doesnt work, swapping it with your Teal.

[dcarrb]

Thanks. I wasn't going to go busting into it unless it was obviously meant to be disassembled; just wondered if zapping the innards with a blast of silicone lube is what everyone considers a "cleaning." I'm always skeptical about such things, but I'm also lazy and didn't want to monkey around with the teal unless really necessary. But for troubleshooting before dropping a chunk of change on a new TPS, I'm thinking that's the way to go.

dcb

[Trevor]

Originally Posted by dcarrb

Thanks. I wasn't going to go busting into it unless it was obviously meant to be disassembled; just wondered if zapping the innards with a blast of silicone lube is what everyone considers a "cleaning." I'm always skeptical about such things, but I'm also lazy and didn't want to monkey around with the teal unless really necessary. But for troubleshooting before dropping a chunk of change on a new TPS, I'm thinking that's the way to go.

dcb

Not a lube which could contain oil. Use CRC or other electrical type cleaner and try to get it in through available spaces, while working the mechanism back and forth. Inside there are wiping contact surfaces, which must make good contact throughout full travel. Refer my stuff in how too.

[dcarrb]

Trevor, I'm not familiar with CRC; normally for something like this I'd use a silicone aerosol lubricant. Have to check the fine print on the brand in my garage to be sure, but I believe this product contains no petroleum distillates. I did read your material in the how-tos and will have it at hand when I get to work, but I have no means to test the unit electrically.

Whatever, I drive the car often and it performs beautifully in every instance except dead-steady throttle, so I'm hopeful that the TPS proves to be the culprit.

Thank you,
dcb

[STORMINORMAN]

1st mark the position of the TPS on the throttle body: I used an X-acto knife and scribed two thin lines onto the plastic & the metal.

Bought the can of CRC/NAPA, etc. contact cleaner, sprayed it into the area that fits over the shaft, swirled it around a bit, drained it out. There was a very little bit of debris, nothing that would change the overall color of the fluid. Everything looked very clean, no carbon, oil, etc. present.

Then I put the very thin straw attachment in the nozzle and sprayed it into the very small hole on the plug side of the TPS. Drained this out and then shot some "compressed air in a can" computer cleaner-type gas through that same little hole. Let it dry in the sun for a couple minutes and re-installed the TPS.

I am not experiencing any problems, power light comes on as it always has, etc. My wife (a couple weeks ago) was driving on the freeway for 50 miles, or so, pulled off and was in a very slow, stop&go, traffic light to traffic light situation when she experienced a single instance of what I would have called "bogging", as if she was lugging the engine in a manual transmision car. No acceleration, major hesitation. She gave me a call & then drove the car back home on the freeway with no further symptoms.

I did the SEARCH here and just followed the instruction in the "how-to-do" with, I hope, total success. After 136+K & 13+ years I guess a little crud can cause a problem or two, but I've been very satisfied with the way the EFI system on the SVX has operated. Got 28+ mpg on the last 500+ mile trip I took so I'm not ready to fix anything that doesn't need fixin'! Only replacement parts in the entire system have been new fuel filters every 30K, a K&N about 60K miles ago & a MAF earlier this year.

Cheers!

[Trevor]

Originally Posted by dcarrb

Trevor, I'm not familiar with CRC; normally for something like this I'd use a silicone aerosol lubricant. Have to check the fine print on the brand in my garage to be sure, but I believe this product contains no petroleum distillates. I did read your material in the how-tos and will have it at hand when I get to work, but I have no means to test the unit electrically.

Whatever, I drive the car often and it performs beautifully in every instance except dead-steady throttle, so I'm hopeful that the TPS proves to be the culprit.

Thank you,
dcb

The thanks are much appreciated. The previous post gives you further excellent advice. A silicone based spray could have insulating properties which is exactly the reverse of improving the internal contact surfaces. Make sure you move the mechanism when spraying.

Check over the mechanical aspects of the throttle operation for sticking cables, pedal etc. Sometimes a simple problem can be overlooked. If the problem persists, you may have to investigate further, including speed sensors and likely cracked tubing associated with the intake manifold. It does not appear that you are involved in anything really expensive. that is if you can stay away from the professionals.

Best of luck, Trevor.

[Sov13t]

Anyone have some pictures on this? I am probably going to be cleaning my TPS this weekend so gathering up on all the knowledge/tips/hints I can get before doing it.

Oh and where can I get this spraY to clean it? which store?

Thanks,
-Sov.

[dcarrb]

Originally Posted by Sov13t

AOh and where can I get this spraY to clean it? which store?

Thanks,
-Sov.

I found the CRC electrical cleaner Trevor mentioned at an O'Reilly Auto Parts, so I'm sure most any parts place would have it. Planning to have a go at mine tomorrow.

dcb

[svx_commuter]

I think that the TPS will just wear out at some point. The contact strips are just going to wear away. If a problem still is there after cleaning it's time to get a new one. I think it is also possible to adjust it out of the worn zone since this most likely close to the idle position.

[floatingkiwi]

Originally Posted by svx_commuter

I think that the TPS will just wear out at some point. The contact strips are just going to wear away. If a problem still is there after cleaning it's time to get a new one. I think it is also possible to adjust it out of the worn zone since this most likely close to the idle position.

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

[floatingkiwi]

Originally Posted by dcarrb

My silver throws unforced downshifts out of the blue when the throttle is held constant (I drive it almost exclusively on curvy backroads and only recently noticed this on a long, straight stretch of highway), and I'd like to try cleaning the throttle position sensor. What exactly is there to clean? Does the unit disassemble, and if I take it apart, will I regret doing so? Should I not bother and just go ahead and swap with the teal? There's already a painted match-mark present, but it doesn't appear the sensor has been removed recently. Tips and suggestions appreciated. Thanks.

dcb

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