Throttle position switch (TPS) repair, Contact surfaces are worn Options

[Cevan]

I've completed my 1.8 to 2.0 motor swap and have my car running really good, except the TPS is worn right around the partially open throttle position.

I've cleaned the surface and the contacts with 2000 grit sandpaper and then used Deoxit electrial contact cleaner. This helped as it only hesitates/bucks at the barely open throttle position and cleared up the issue at positions further along the path of travel. I imagine that it's worn right at the spot where you're most often running at.

I searched but couldn't find any threads on repairing this. What I want to do is move the circuit board to the right or left, so that the contacts run on a fresh part of the board. Any ideas on how to separate the circuit board from the metal body and how best to reattach it? It looks like it may be soldered at the bottom right corner.

[JeffBowlsby]

Thanks for making these Dave...we have been in need for too long.

Can you tell us why you did not select a screw and used a rivet?

[davesprinkle]

Thanks for making these Dave...we have been in need for too long.

Can you tell us why you did not select a screw and used a rivet?

Jeff,

I considered a screw. You could make it work, but here's why I didn't:
1. OE hole is roughly 1.5mm diameter. Tiny.
2. You could thread the baseplate, but a few problems are: 1.5mm base thickness means very few threads, most people don't have tiny taps, and tapping is very error-prone (some people would be successful, but probably 50% wouldn't).
3. You could use a screw/nut combination, but only at the risk of the tiny fastener coming loose. Locknuts aren't available in smaller than 3mm, so you'd be drilling out the hole anyway.
4. Those tiny fasteners are fiddly and disproportionately expensive.

So much for the cons, here are the pros:
1. A rivet will hold tight.
2. A rivet won't fail due to engine heat.
3. A rivet is cheap.
4. A rivet is so easy to install, a caveman could do it.

I wish I could have gotten a pop-rivet that matched the factory diameter, but no luck. I don't like having to drill out the baseplate, but I think on balance it's the best choice -- functionality at the expense of a slight deviation from the factory design. I know the tradeoff won't work for Pat Garvey (bless his concours heart), but the rest of us will probably agree it's worthwhile.

[warrenoliver]

Thanks for making these Dave...we have been in need for too long.

Can you tell us why you did not select a screw and used a rivet?

Jeff,

I considered a screw. You could make it work, but here's why I didn't:
1. OE hole is roughly 1.5mm diameter. Tiny.
2. You could thread the baseplate, but a few problems are: 1.5mm base thickness means very few threads, most people don't have tiny taps, and tapping is very error-prone (some people would be successful, but probably 50% wouldn't).
3. You could use a screw/nut combination, but only at the risk of the tiny fastener coming loose. Locknuts aren't available in smaller than 3mm, so you'd be drilling out the hole anyway.
4. Those tiny fasteners are fiddly and disproportionately expensive.

So much for the cons, here are the pros:
1. A rivet will hold tight.
2. A rivet won't fail due to engine heat.
3. A rivet is cheap.
4. A rivet is so easy to install, a caveman could do it.

I wish I could have gotten a pop-rivet that matched the factory diameter, but no luck. I don't like having to drill out the baseplate, but I think on balance it's the best choice -- functionality at the expense of a slight deviation from the factory design. I know the tradeoff won't work for Pat Garvey (bless his concours heart), but the rest of us will probably agree it's worthwhile.

How about JB Weld? Wouldn't that work even better? (IMG:style_emoticons/default/poke.gif)

(IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif)

Nice job on the board, I'll be interested in the test results.


Warrenoliver

[davesprinkle]

How about JB Weld? Wouldn't that work even better? (IMG:style_emoticons/default/poke.gif)

(IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif)

Nice job on the board, I'll be interested in the test results.


Warrenoliver

Funny that you mention adhesive, Warren, because that's exactly what the factory used to secure the board on the early 1.7 liter cars. I just learned this today when I opened up a 1.7 liter TPS. Although the boards are similar, they will NOT interchange. And as I mentioned, the early 1.7 liter board is glued in place, rather than riveted.

So for now, I don't have an early 1.7 liter solution. (But when I do, JB Weld might be part of it...)

Meanwhile, I'm still on the hunt for a 2.0 liter validation platform. Stand by.

PS. Thanks to Britain Smith for dissassembling his car for me.

[warrenoliver]

How about JB Weld? Wouldn't that work even better? (IMG:style_emoticons/default/poke.gif)

(IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/av-943.gif)

Nice job on the board, I'll be interested in the test results.


Warrenoliver

Funny that you mention adhesive, Warren, because that's exactly what the factory used to secure the board on the early 1.7 liter cars. I just learned this today when I opened up a 1.7 liter TPS. Although the boards are similar, they will NOT interchange. And as I mentioned, the early 1.7 liter board is glued in place, rather than riveted.

So for now, I don't have an early 1.7 liter solution. (But when I do, JB Weld might be part of it...)

Meanwhile, I'm still on the hunt for a 2.0 liter validation platform. Stand by.

PS. Thanks to Britain Smith for dissassembling his car for me.

The Cap'n will have yer hide for suggesting that! (IMG:style_emoticons/default/laugh.gif)


Warrenoliver