My 2005 Subaru Legacy needs a throttle position sensor, which is built into the $600 throttle body assembly. I picked up a used one from a local Subaru junkyard, but it's pretty nasty looking inside and out. What's the best way to clean this thing up without destroying the plastic sensor assembly?
I don't have a photo of mine, but this is pretty representative of its condition.
I've used brake cleaner on the inside with luck, no ideas on the outside. Maybe blue masking tape and the DIY soda blaster in the tech tips section?
This might sound silly, but I use CRC's "Throttle body cleaner" spray.
Throttle body cleaner will be step one. Dare I try Zep-alum?
I'd be pretty careful with toxic chemicals or blasting. Clean the important stuff (the throat and throttle plate) and ignore the rest. Shiny doesn't make it work better.
I've also got some small wire brushes for the Dremel.
I cant tell by looking at it, but if it DBW do not manipulate the blade. If it was really dirty, Id soak it in thinner or something like that IF I could keep the electrical parts out of it.
If not Id use throttle body cleaner and some brushes.
how precious is the junkyard assembly? The metal clips holding the plastic look removable - wonder if the circuit board is screwed in - or play with the trashed one - how does it come apart?
It's precious to the tune of a hundred bucks. It looks like there's some kind of epoxy behind the metal clips.
hmm, think I'd tape off the electronics a bit of throttle body cleaner for the bore and maybe the dremel wire brushes on the outside - and try a little operation on the old one...
As far as the outside: Rustoleum Hammered.
A lot of people like that high-temperature "Grill Paint" that Rustoleum makes. It goes on anything, is heat-resistant (obviously), glossy-black, and pretty much bulletproof. Your mileage may vary, professional driver on closed course, do not try this at home, etc.
+1 for throttle body cleaner and not manipulating the valve if it's DBW (which it looks like it is)
why do you not want to move the butterfly?
It could damage mechanisms inside, either the servo or the position sensor depending on how it's made.
We'll see what happens. The butterfly has been moved on both already. It would be impossible to get them clean without doing so.
Well if you're lucky, nothing will be damaged and you'll just have to get the ECU reset to relearn the throttle position. Seems dumb but that's how they work.
How about one of the ultrasonic cleaners from HF?
I believe that TPS is replaceable and the sealant is just to keep water out of there. It has been a while since I looked at one of those.
Here is the part I think you would need on eBay. http://www.ebay.com/itm/like/150711769544?lpid=82
Rockauto also lists them as a separate part as well.
oven cleaner and bake
Old tooth brush works well.
dean1484 wrote: I believe that TPS is replaceable and the sealant is just to keep water out of there. It has been a while since I looked at one of those. Here is the part I think you would need on eBay. http://www.ebay.com/itm/like/150711769544?lpid=82 Rockauto also lists them as a separate part as well.
I've been getting mixed info on this. I've seen both listed as the TPS. The yard that I bought the part from really knows this stuff. They had hundreds of cars and I didn't notice a single non-Subaru. I told the guy that I needed a TPS for a 2005 Legacy 2.5i. He asked if the car had California emissions (it does) and he knew the part number off the top of his head. I didn't have the part with me, but the number matches, even though it's a one year only part. He said that they fail all the time.
The bore and butterfly cleaned up nicely with sensor friendly TB cleaner and a toothbrush and some WD40 made the outside look a little more presentable. I'll know more tomorrow when I swap it in.
UPDATE:
Success! Details at 11.
So, here's the deal...
The Googles weren't really clear about which sensor was giving me trouble. It appears that in the Subaru world, all the cool kids have turbos, and all the internet chat focuses on them, so I had to take turbo answers and try to figure out how the info translated to the normally aspirated world.
When I went to the junkyard, I thought I needed the sensor that Dean linked above. The guy at the counter really seemed to know his stuff and when I told him what was going on, he went right to the throttle body assembly. The one he sold me was a mess, but I cleaned it up, made a new gasket and installed it. The car fired right up, but I still had a check engine light on. It would come back as soon as I cleared the code. After a couple of attempts, I noticed that I was no longer clearing the same code. Now it was showing P2016 (Intake manifold runner position sensor / switch, circuit low, bank 1). Back to Google, this code pointed to the sensor that Dean linked. The "Bank 1" part threw me. I'm not certain, but I think turbo cars have three of these sensors, but my car only seemed to have one, so "Bank 1" didn't really mean much to me. I had removed it a couple of days ago to get a better look at the part number and then reinstalled it. I read a couple of comments about how to install them and they mentioned that they have a clock spring that needs to be properly indexed. I knew that I hadn't done that when I reinstalled it, so I removed it, clocked it properly and reinstalled it. After clearing the code once again, everything else was back to normal and the light stayed out.
Honestly, I'm not sure if just removing and cleaning up my old throttle body assembly would have been enough to solve the problem, but if I hadn't gone to the junkyard, I would have been going after the wrong sensor anyway. I didn't have enough time to swap the old one back in again after I cleaned it up, so I'm not sure if it's any good or not. If these things really do fail all the time, I'll have a spare on the shelf to try before shelling out for another. I spent $107 on the used throttle body and learned some stuff about Subarus, so I'm not too upset about that. These were fairly easy parts to swap.
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