Article: Cleaning the Throttle Body

[timsrv]

Tim,

i have the throttle body in my hands and i'm watching your video how to adujst TPS. On my 1988 repair manual, the values for continuity and discontinuity are 0.0224 and 0.0335. Why are you using different gauge thickness for checking continuity (0.028)?

Also, inside the intake is full of black stuff. what do you suggest to remove it?

thanks a lot

Jerome

You're using the manual.............Awesome! The transition from continuity to no continuity can occur anywhere between .0224" - to .0335". If you're testing/checking and you're in that range, it's good enough. If you're going to the trouble to set it up, it's my opinion you should go for being as close as possible (I'm trying to hit that spot exactly in the middle). If you do the math, .0275" is the number exactly in the middle of .0224 - .0335. (.028" is the closest feeler gauge you're going to find..............unless you have a .70 mm feeler gauge). Tim

PS: How thick is the black stuff? Being black inside the intake is okay............assuming it's just colored black. It's not crusty or caked.......right?

[filterway]

You're using the manual.............Awesome! The transition from continuity to no continuity can occur anywhere between .0224" - to .0335". If you're testing/checking and you're in that range, it's good enough. If you're going to the trouble to set it up, it's my opinion you should go for being as close as possible (I'm trying to hit that spot exactly in the middle). If you do the math, .0275" is the number exactly in the middle of .0224 - .0335. (.028" is the closest feeler gauge you're going to find..............unless you have a .70 mm feeler gauge). Tim

PS: How thick is the black stuff? Being black inside the intake is okay............assuming it's just colored black. It's not crusty or caked.......right?

when i bought the van the manual was included!

after my post i realized that 0.028 is the middle of (0.0224+0.035)/2. I was unable to do like you in your video (reaching the point of continuity/dsicontinuity) because there was a gap to reach that point when i turn clockwise, and counterclockwise.In other word i had to turn more on clockwise then counterclockwise to reach that point (???!!) i'm not sure i'm clear it's hard to explain. But finally adjustment of TPS was perfect and the van work fine.

The old TPS was broken in is shaft.

for the black stuff, it's not caked but some place was thicker thans just a film of black dirt. what it means if it's crusty or caked?

Jerome

[timsrv]

for the black stuff, it's not caked but some place was thicker thans just a film of black dirt. what it means if it's crusty or caked?

Jerome

Typically you won't see crusty/caked in the throttle body area of our vans. Crusty/caked typically occurs where the PCV line enters the manifold (which is close to the valve cover on the van manifold). Over time, especially on worn engines with "blow by", they will build a black crusty cake of residue in this area. Eventually this can clog the PCV passage and there's a small potential for it to break-off and get into a cylinder. If you have good vacuum at your PCV port, then I wouldn't worry about it. Tim

[wavegobbler]

I am having a mixed experience attempting the Throttle Body cleaning. My main issue is a lack of ability to follow directions. When I disassembled the throttle body, I did not scratch the original orientation of the disk. It did not seem like a big issue, the 'engine side' had the most crud build up and I could still see its traces after the solvent dip. Given that I had some confidence in which side was which, It only seems to 'seat' in one orientation. But just to check, I tried the other side, and it also seemed to work in one orientation. The catch, is that neither orientation passes the 'light test'. Its tight but not air tight. If I did not have timrv's great write up, I would assume the disc was symmetrical, one side is the exact opposite of the other side and the bore is completely symmetrical. The disk would have two possible orientations. But, it's more likely I'm doing it wrong.

So, sorry to ask a question already answered in the thread, but, does the disk always pass the light test perfectly? I've spun it around and around without getting a perfect seal.

I'm attaching a photo of the disk, I have the throttle very slightly open, you can just see one of the ports, in the bore, starting to show. Maybe my orientation in completely off. Does that look right?



The next failure to interpret directions well, involved the rubber cover for the idle adjust screw. I looked at the two ground 'flats' that timrv put on the metal stud and thought they were there so he could get a wrench on it, not so he could just pop the rubber past the tight spots. I yanked out the stud and its not very pretty after my abuse. I had to replace it with a plastic male/female part that I pulled out of a random part drawer at the local hardware store. I will see if it can handle the heat.

Don't yank out the stud holding the rubber cover.


Another issue involved a rattle sound coming from the new TPS. I had to take it apart and put a rubber corner piece in its correct location.
Timrv's video on how to set the TPS is pure gold.
Any comments on peoples experiences getting the disk to seat airtight would be much appreciated.

[timsrv]

After installing and lubing the shaft seals, the very next step is installing the shaft, disc, and seating to the correct orientation (before any other assembling). Once you put the cable guide on the throttle shaft the "throttle stop screw" will interfere and prevent complete closing of the disc. Don't mess with the throttle stop screw as it's set at the factory and should never need to be adjusted.

Take the cable guides and springs back off and do the disc alignment over again. If you've already installed the TPS, I'd advise taking that back off just so you can have full control over throttle shaft while setting/adjusting. Tim

BTW, you could be right about the disc being symmetrical (at least when flipped 180 deg). Whatever way works I guess is good enough. There's always springs and things you could add later if the throttle doesn't want to close all the way . I can be a bit anal I guess. I'm set in my ways and tend to be so unyielding that others will sometimes ridicule me for it. It's my personal choice to try & put things back exactly as before as to reduce my chance of potential problems. Tim

[wavegobbler]

Thank you Tim for replying to my question.
One positive is that my throttle does close all the way. In the photo I was holding it open, trying to establish a reference point. Its hard to describe how the disk is set in the body, so I just opened it a hair, and you can just see a port exposed. I'm hoping thats normal.

The disk sits tight in the body in two orientations. With out the back light, it looks tight. But if you hold it up to a light, you can see light around the edges. When you hold up the assembled body to the light, is there NO light filtering through on the edges? I could not get it that tight.

I flipped it a bunch and never got a completely 'dark' fit (NO light at edge). I was fitting it before any of the other assembly, with the two screws loose. Do you think it might still work?

Thanks,
(another)Tim

[wavegobbler]

Once again, I score low marks in reading comprehension.

I just re-read Tim's response to my original question. I think that my disk is set tight in the body. Once its assembled, the 'Throttle Stop Screw' is holding it slightly open. I was confused because I thought it was tight but after assembly, its barely gapped.

Thank you again Tim for your answer. The Throttle Stop Screw was not on my radar even though its right there. I think my Throttle body is ready for service, I hope thats not just wishful thinking.

Tim

[timsrv]

Awesome! Let us know how it works out. (the original)Tim

[AD2101]

Tim! Anyone!! Van down!!!

I may have bitten off more than I can chew with this one. Some hoses were thrashed getting the throttle body out of the van, which I expected since nearly all the hoses were 27+ years old. What I did not expect was this when I finally got my throttle body taken apart.



As you can see, half of one of my inlets (I don't know the proper term, ) has corroded/rusted off. Is this salvageable? If not, can these be replaced or is my throttle body basically shot? The usable remainder of the stub is long enough to get a hose and a hose clamp onto so I'm hopeful that it is, but not sure. This repair has gone about as badly as it could have gone so far, I also wasn't able to remove the butterfly screws and they are completely stripped. I ground them down flush beforehand and tried to follow your advice but the metal was just too soft. Anyone have any luck drilling these out and then backing them out with an easy out? Anyone have any advice at all? HELP!

EDIT: After wrenching on this some more the butterfly screws are out, so I'm just back to the original question about the busted inlet in the photo.

[timsrv]

Perhaps a machinist could drill those out and press in new nipples??? I don't know. When I see them like that I start looking for another throttle body. Tim

[ratatouille]

I'm dusting things off and finding time to start working on my van again. Top of my list is this TPS work. I am wondering though as I look closer, my throttle body may either have been replaced or this work has been done before..I think. When I had hoses off peeking in the best I could, things don't look dirty at all really. Is it possible to replace TPS with out removing throttle body?

[timsrv]

Anything is possible, but that lower screw on the TPS is a bugger. I probably would have tried this by now, but every time I've needed to address a TPS, the throttle body looked all crusty, so I just pull the whole assembly and do together. If you just want to check the TPS without removing, I give instructions for that in THIS POST. Tim

[ratatouille]

Thanks Tim. Not sure which is best thread to continue my questions on. This or the thread you mentioned. Went to test the TPS as you outlined in that thread and I'm not getting any tones from multimeter when hooked up to the paper clips. Double checked I've got it hooked in correct E1 and IDL pins. Throttle stop and adjuster screw are touching. No tone with or without feeler gauges. What to do next ? My first thought is TPS is no bueno. But with no-tone could this mean I've got issues with a connection somewhere else? TPS connection looks properly seated.

[ratatouille]

Gave it a good try but couldn't figure out out how to get a good grip on the bottom screw. Tired of the bloody knuckles went ahead and removed the throttle body to remove TPS. Skipping the chem bath because thing really do look pretty dang clean. Even still have what looks like fresh paint marker where the factory marked thing ups. OG TPS removed and opening it up I can see why I was not getting any tone. Plastic not rotating gall the way to force the contacts together... New TPS coming from Amazon tomorrow.

I noticed when I removed throttle body I've got some build up right on the inside of the intake. I'd like to scrape the crustiness out but wondering why I've got it there? Reason for concern?


sorry for the blurry picture...looks like gunk is surrounding a hole there?


Thanks a lot.

[gushaman]

I thinkni look at this thread more than any other! Im trying to figure how difficult it would be to replace the two coolant pipe nipples on the throttle body. My girlfriends van is getting a new tps, and the pipe nipples are corroded. They may work ok and seal to the rubber hose with a good napa clamp, or i may put a layer or two of some good tape. I cleaned them with flapper wheel, but the ridges are worn, and the wall thickness is decreased.

I thought i remembered a thread on pipe nipple replacement but couldnt find it.

[timsrv]

I scrapped one due to rusty nipples that looked like Swiss cheese. I considered replacing, but looked as though the only way would be to drill out. So if you go to all that trouble, where do you get new nipples? I figured it wasn't worth the effort and just pulled another one off one of my parts vans. Every so often these also come up on eBay for a reasonable price. Good luck. Tim

PS: Sorry ratatouille for not answering your post. I'm just now seeing it. I run my own business and I'm always swamped that time of year. I hope you got it all figured out. Tim

[gushaman]

Fingers crossed, then. Thanks tim!

[ratatouille]

... Sorry ratatouille for not answering your post. I'm just now seeing it. I run my own business and I'm always swamped that time of year. I hope you got it all figured out. Tim

No worries Tim. I'm in the same boat as a small business owner. So swamped... Unfortunately I've had issues since replacing TPS and cleaning throttle body, I don't think related, but haven't had time to research and work on them quite yet. Soon I hope!

[AR74]

Can someone tell me what the Throttle Stop Screw setting is from the factory ? Mine abviously has been tampered with and I need to set it back to factory setting so I can adjust my idle correctly.

[timsrv]

Read post #9 in this thread.