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

[davesprinkle]

Here is a pic with the connector reinstalled onto the sensor base. I found that the plastic of the connector cracked when I removed it from the base, so now, it isn't held as securely. You'll avoid this possibility if you leave the connector in place when doing the board replacement. It'll be a little more difficult to get the board into place under the connector contacts, but the business-card trick will be helpful.

[McMark]

Two sites, same content, same users

(IMG:style_emoticons/default/av-943.gif) Yeah, about 1% of the same content and same users.

[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?

[Katmanken]

Gee Jeff,

The answer to that is obvious....

Concours weenies wouldn't buy them if a screw was used......

[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.

[JeffBowlsby]

That seems well thought out Dave. While a screw could be used, it may loosen up and a rivet can always be drilled and replaced in kind. Kudos too you.

Can you sell these direct or is the only way to get them is through BRAG?

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.

[davesprinkle]

That seems well thought out Dave. While a screw could be used, it may loosen up and a rivet can always be drilled and replaced in kind. Kudos too you.

Can you sell these direct or is the only way to get them is through BRAG?

Jeff, either one of us will take your money. $35.00 for the board and the rivet. I'll need a week or so to validate the design on a running car before I'm ready to start shipping.

[RoadGlue]

Subscribed to this thread. This looks awesome. Nice job! I'll purchase one, maybe two, once they're ready to ship.

[JeffBowlsby]

Thats great! I would be happy to be a 2.0L mule for you if you need one.

That seems well thought out Dave. While a screw could be used, it may loosen up and a rivet can always be drilled and replaced in kind. Kudos too you.

Can you sell these direct or is the only way to get them is through BRAG?

Jeff, either one of us will take your money. $35.00 for the board and the rivet. I'll need a week or so to validate the design on a running car before I'm ready to start shipping.

[Tom]

Dave,
Outstanding job. I remember doing some small PC boards back in electronics school. We used a photo etching process for them. Wish I had a 914 back then. Ha. I'm in for one when you start shipping. Again really nice work.
Tom

[Cevan]

Even though I fixed mine (at least temporarily), I'll be getting one of these once they've been tested.

Question: Is the conductive material on the board as durable as the original?

[davesprinkle]

Question: Is the conductive material on the board as durable as the original?

Cevan, if you look closely at the pics, you can see marks on the board from the wiper contacts. So it's valid to question the durability of the board. A few points of explanation:

1. For some reason, the marks appear more prominent in the pic than they do in person. I guess something to do with the reflective trace material?
2. Having said that, there is definitely a burnished region where the contacts run, just as with the factory design. We've got a spring-steel contact rubbing across a tin-plated copper trace. Witness mark are inevitable. It's definitely not "serious wear" though. (At least not yet -- it will be serious someday, but it will take a while.)
3. I called out a copper thickness roughly twice what the factory used. I also called out a tin plate, which is why these tracks are silver-colored, as opposed to the factory's raw copper. I would expect these new tracks to last at least as long as the factory design, and probably much longer. Sorry, won't last forever, though.

[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

[davesprinkle]

Everyone, I still haven't found a suitable test platform. I'm looking for a 2.0 liter car, running the stock djet fuel injection in the Portland, OR area. The car should have a bad TPS, but should have no other FI-related problems.

If you have such a car, please let me know. I will install a new TPS board at no expense to you.

Thanks.

[sixnotfour]

dave a ,local shop told me AA has the boards too ? can you confirm ?
yours ? or their own ?

[davesprinkle]

dave a ,local shop told me AA has the boards too ? can you confirm ?
yours ? or their own ?

Probably mine. Last week, George expressed interest in purchasing them. When we spoke, he didn't indicate that he had another source.

Glad to hear he's preselling them. Now I just need to get a validation platform...

[davesprinkle]

I've got a late 1.7liter TPS here. It appears to rotate backward from the 2.0liter.

Can anybody verify that the 1.7liter djet throttlebody rotates backward from the 2.0liter throttlebody?

Thanks.

(By the way, although the two boards (late 1.7liter and 2.0liter) are identical in shape, they differ slightly in their copper pattern. Hence, the 1.7 will require a new board.)

[Derek Seymour]

(IMG:style_emoticons/default/icon_bump.gif)