Printable Version of Topic

Click here to view this topic in its original format

914World.com _ 914World Garage _ Throttle position switch (TPS) repair

Posted by: Cevan May 11 2009, 11:47 AM

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.

Attached Image

Posted by: McMark May 11 2009, 11:50 AM

Using careful pressure, you can slightly bend the 'fingers' to run on a new area of the circuit board. No need to make it more complicated than that.

Posted by: Cevan May 12 2009, 05:39 AM

Thanks McMark. I did as you suggested and gently pulled the contact arm out a little and got it to run on a new path just outside of the existing path. Put it all back together and reinstalled it, calibrated it and drove it. No more hesitation/bucking. Problem solved. smilie_pokal.gif

Posted by: Derek Seymour Jun 15 2009, 02:20 PM

I think this may have already been mentioned, but Otto is out of the new TPS's.

He instructed me to use a pencil eraser on the switch, which works really really well. The contact strips on mine are bright and shiny now and my bucking is gone.

However judging from the grooves I would venture to guess that I will need a new one eventually.

I was looking into using Eagle CAD to make a schematic and then exploring options for having them manufactured.

Is anyone else doing this? I don't want to jump in on a project that is already being done, nor do I want to compete with anyone.

Is there any interest from the community in having these made?

Posted by: rjames Jun 15 2009, 02:23 PM

QUOTE(Derek Seymour @ Jun 15 2009, 01:20 PM) *

I think this may have already been mentioned, but Otto is out of the new TPS's.

He instructed me to use a pencil eraser on the switch, which works really really well. The contact strips on mine are bright and shiny now and my bucking is gone.

However judging from the grooves I would venture to guess that I will need a new one eventually.

I was looking into using Eagle CAD to make a schematic and then exploring options for having them manufactured.

Is anyone else doing this? I don't want to jump in on a project that is already being done, nor do I want to compete with anyone.

Is there any interest from the community in having these made?



There's always interest for repro parts. This part is a popular candidate. Of course it will always come down to how much they will co$t. smile.gif

Posted by: Cevan Jun 15 2009, 02:31 PM

I fixed mine in about 10 minutes, from start to finish. It should be good for another 50,000 miles or so. That fix might kill the market for this part.

Posted by: Derek Seymour Jun 15 2009, 03:29 PM

It may kill it for some but for others I suspect that cleaning won't be enough. I just noticed a hestitation or two while driving at lunch 5 minutes ago. Not nearly as drastic as it was before, but still noticeable. It may have something to do with the deceleration fuel cut-off since mine is a '76 confused24.gif. But I'm guessing my TPS is just a little to worn in some spots.

Does anyone know what Otto was selling his units for? If it was somewhere between $150-$200 then it getting these made would be doable depending on the number produced at intial manufacture. SRP any less than that and it would be a loss.

Posted by: r_towle Jun 15 2009, 05:11 PM

Isnt that gold?
Could gold leafbe applied tofix the groove?
Even silver solder might work?

Rich

Posted by: davesprinkle Jun 15 2009, 07:14 PM

I have a board house manufacturing these circuit boards right now. I expect the shipment on 22 June 09.

Posted by: Derek Seymour Jun 15 2009, 08:09 PM

QUOTE(davesprinkle @ Jun 15 2009, 06:14 PM) *

I have a board house manufacturing these circuit boards right now. I expect the shipment on 22 June 09.



Awesome!!! Then I will drop the whole idea and buy one from you. Thanks for doing that!!!!!

Posted by: Pat Garvey Jun 15 2009, 08:37 PM

The the original on my 72 was never as worn as yours, I puleld it for grins & used a jeweler's rouge cloth on it. Of course, you can't remove all of the groove, but it did clean up the groove & made better contact. Seems to work just fine - no bucks, etc.

I have a brand new one on the shelf, so there was so relief in knowing that if I screwed the original I could just slap on the new one.
Pat

Posted by: Gint Jun 15 2009, 08:54 PM

QUOTE(McMark @ May 11 2009, 10:50 AM) *
Using careful pressure, you can slightly bend the 'fingers' to run on a new area of the circuit board. No need to make it more complicated than that.

Now that's a pretty simple damn solution (SDS get it?)!

Posted by: davesprinkle Jun 22 2009, 08:49 AM

Circuit boards arrived. Here's a pic. Testing this week.


Attached image(s)
Attached Image

Posted by: davesprinkle Jun 22 2009, 03:37 PM

More pics of initial board installation in http://www.914club.com/bbs2/index.php?showtopic=150982&pid=1042995&st=20&#entry1042995 over on the club site.

Posted by: McMark Jun 23 2009, 01:00 AM

dry.gif Posting pictures here is apparently difficult.

Posted by: kwales Jun 23 2009, 09:46 AM

Yeah, that's a really good picture on the other site...
It looks just like this.......

"This pic shows how the connector sits slightly higher due to the now-loose fit. (The connector should sit flush with the metal base.)

Attached File(s)
DSCN3982.JPG ( 722.59K ) Number of downloads: 3"


And It won't download....


Posted by: davesprinkle Jun 23 2009, 09:50 AM

QUOTE(McMark @ Jun 23 2009, 12:00 AM) *

dry.gif Posting pictures here is apparently difficult.

No, not difficult. Just frustrating. Two sites, same content, same users. It's easier to post a link than to redo the whole thread. Whatever, here ya go...

First, drill out the hole for the factory rivet to 3/32". The rivet hole in the new board is sized for a 3/32" pop rivet, which will be included with the board. For those who have forgotten what a drill-bit looks like, here is a pic:




Attached image(s)
Attached Image

Posted by: davesprinkle Jun 23 2009, 09:51 AM

A business card makes a good ramp for getting the wipers onto the board.



Attached image(s)
Attached Image

Posted by: davesprinkle Jun 23 2009, 09:51 AM

Here's a pic of the board with the business card removed. No rivet yet.



Attached image(s)
Attached Image

Posted by: davesprinkle Jun 23 2009, 09:54 AM

Rivet installed. I would urge you to fend off the temptation to step up to a 1/8" diameter rivet. The larger head will short out the trace on the board. The correct rivet will be included with the board. Use it.


Attached image(s)
Attached Image

Posted by: davesprinkle Jun 23 2009, 09:56 AM

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.



Attached image(s)
Attached Image

Posted by: McMark Jun 23 2009, 11:08 AM

QUOTE
Two sites, same content, same users

av-943.gif Yeah, about 1% of the same content and same users.

Posted by: Jeff Bowlsby Jun 23 2009, 01:51 PM

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?

Posted by: kwales Jun 23 2009, 01:59 PM

Gee Jeff,

The answer to that is obvious....

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

Posted by: davesprinkle Jun 23 2009, 02:19 PM

QUOTE(Jeff Bowlsby @ Jun 23 2009, 12:51 PM) *

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.

Posted by: Jeff Bowlsby Jun 23 2009, 02:36 PM

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?

QUOTE(davesprinkle @ Jun 23 2009, 01:19 PM) *

QUOTE(Jeff Bowlsby @ Jun 23 2009, 12:51 PM) *

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.


Posted by: davesprinkle Jun 23 2009, 02:39 PM

QUOTE(Jeff Bowlsby @ Jun 23 2009, 01:36 PM) *

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.

Posted by: RoadGlue Jun 23 2009, 03:12 PM

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

Posted by: Jeff Bowlsby Jun 23 2009, 03:17 PM

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

QUOTE(davesprinkle @ Jun 23 2009, 01:39 PM) *

QUOTE(Jeff Bowlsby @ Jun 23 2009, 01:36 PM) *

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.


Posted by: Tom Jun 23 2009, 03:49 PM

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

Posted by: Cevan Jun 23 2009, 04:30 PM

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?


Posted by: davesprinkle Jun 23 2009, 06:45 PM

QUOTE(Cevan @ Jun 23 2009, 03:30 PM) *

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.

Posted by: warrenoliver Jun 24 2009, 05:02 PM

QUOTE(davesprinkle @ Jun 23 2009, 03:19 PM) *

QUOTE(Jeff Bowlsby @ Jun 23 2009, 12:51 PM) *

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? poke.gif

av-943.gif av-943.gif av-943.gif

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


Warrenoliver

Posted by: davesprinkle Jun 25 2009, 12:53 AM

QUOTE(warrenoliver @ Jun 24 2009, 04:02 PM) *



How about JB Weld? Wouldn't that work even better? poke.gif

av-943.gif av-943.gif 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.

Posted by: warrenoliver Jun 25 2009, 11:25 AM

QUOTE(davesprinkle @ Jun 25 2009, 01:53 AM) *

QUOTE(warrenoliver @ Jun 24 2009, 04:02 PM) *



How about JB Weld? Wouldn't that work even better? poke.gif

av-943.gif av-943.gif 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! laugh.gif


Warrenoliver

Posted by: davesprinkle Jun 29 2009, 10:23 PM

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.

Posted by: sixnotfour Jun 29 2009, 11:27 PM

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

Posted by: davesprinkle Jun 29 2009, 11:44 PM

QUOTE(sixnotfour @ Jun 29 2009, 10:27 PM) *

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...

Posted by: davesprinkle Jun 30 2009, 02:26 PM

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.)

Posted by: Derek Seymour Jul 1 2009, 11:46 AM

icon_bump.gif

Posted by: rjames Jul 1 2009, 01:36 PM

I'm wishing my Seattle teener was in Portland to be a guinea pig for you. I'll be looking into whether the TPS is the root of some hesitation issues soon. At least I know where to get one if needed.

Great job making this part available again! beer.gif



Posted by: davesprinkle Jul 6 2009, 09:29 PM

Jeff Bowlsby installed the board on his 2.0liter. His initial report is that the car runs as intended with the replacement board.

I've still got a tentative 2nd validation car lined up in Seattle this week. I'm getting close to releasing these for purchase.

Posted by: sixnotfour Jul 6 2009, 09:45 PM

QUOTE
I've still got a tentative 2nd validation car lined up in Seattle this week.


Thanks for helping Mark . Jeff

Posted by: Mikey914 Jul 6 2009, 09:55 PM

I have a 76 2.0 that is local. Unfortunately, I still have some issues that I'm trying to work out. It runs, but after it gets warm the idle drops down. If you just want to check function it could work for you.

Just PM me.

Posted by: RoadGlue Jul 19 2009, 12:08 AM

Bump! I REALLY want two of these ASAP. smile.gif Any progress? Taking the 914 from Santa Rosa to San Diego and back in mid-august and I'd love to have at least one before I leave. My other 914 could use one too! Both are 2 liter cars with stock FI.

Posted by: davesprinkle Aug 24 2009, 10:53 PM

OK everybody, sorry for the delay. I've completed the testing of the boards. $35.00 each. Ready to ship.

Posted by: RoadGlue Aug 24 2009, 11:49 PM

Hooray! How do we order?

Posted by: davesprinkle Aug 25 2009, 08:42 AM

QUOTE(RoadGlue @ Aug 24 2009, 10:49 PM) *

Hooray! How do we order?


You can either send me a Paypal (contact me via PM for address) or you can order through BRAG via the other site.

Posted by: RoadGlue Aug 25 2009, 03:35 PM

I ordered two! Who's next?

*bump*

Posted by: davesprinkle Aug 25 2009, 06:37 PM

QUOTE(RoadGlue @ Aug 25 2009, 02:35 PM) *

I ordered two! Who's next?

*bump*

Randy, I sent out your boards today. Thanks for the order.

Posted by: davesprinkle Jan 28 2010, 09:15 PM

I just received the boards for the late 1.7liter cars. (Please note that these boards will not work on the early 1.7 cars. Completely different switches.) Sorry that this has taken so long. Here's a pic:


Attached thumbnail(s)
Attached Image

Posted by: pbanders Jan 29 2010, 10:44 AM

Dave, this is all great stuff! Awesome engineering, planning, and implementation, too!

One other suggestion I would recommend to people who are replacing their TPS boards, and to owners who have board that are still working well, is to consider using a contact lubricant to reduce wear on the wiping trace. Two products are Deoxit D-5 and Stabilant 22. Both should extend the life of the TPS by reducing trace wear.

Note that because most of the wear happens near the start of the trace, because this is the area where you spend most of the time at part-load with a small throttle opening, while cruising.

Dave, I'll update my parts page with info on your board replacement.

Posted by: Rod Jan 29 2010, 12:29 PM

QUOTE(davesprinkle @ Jan 29 2010, 03:15 AM) *

I just received the boards for the late 1.7liter cars. (Please note that these boards will not work on the early 1.7 cars. Completely different switches.) Sorry that this has taken so long. Here's a pic:



Mines a March 1973 1.7l, would this be correct for your new tps? Mine is filthy, so If correct I would love one..

Please let me know... rodsrugs(at)me.com

Posted by: davesprinkle Jan 29 2010, 07:12 PM

QUOTE(Rod @ Jan 29 2010, 10:29 AM) *

QUOTE(davesprinkle @ Jan 29 2010, 03:15 AM) *

I just received the boards for the late 1.7liter cars. (Please note that these boards will not work on the early 1.7 cars. Completely different switches.) Sorry that this has taken so long. Here's a pic:



Mines a March 1973 1.7l, would this be correct for your new tps? Mine is filthy, so If correct I would love one..

Please let me know... rodsrugs(at)me.com


Yes, this board will work for your car.

Posted by: McMark Feb 3 2010, 11:29 PM

Dave, could you add something in the Member Vendor forum? You'll probably sell more. wink.gif

Posted by: johnwmrvw Feb 10 2010, 09:44 PM

Hello, I'm interested in your circuit board. I live in Vancouver and work in Portland
(Gladstone to be exact) please reply and I can give my contact info!
thank you, John

Posted by: mikeg4 Feb 16 2010, 08:31 PM

[quote name='davesprinkle' date='Jun 15 2009, 05:14 PM' post='1181084']
I have a board house manufacturing these circuit boards right now. I expect the shipment on 22 June 09.
[/quote
I'd like to purchase a few of your boards.Are they still available?Do you have a 2 liter version?

Posted by: davesprinkle Feb 16 2010, 09:02 PM

QUOTE(mikeg4 @ Feb 16 2010, 06:31 PM) *

QUOTE(davesprinkle @ Jun 15 2009, 05:14 PM) *

I have a board house manufacturing these circuit boards right now. I expect the shipment on 22 June 09.

I'd like to purchase a few of your boards.Are they still available?Do you have a 2 liter version?


Yes, I've got boards available for both the 2.0liter and late 1.7liter cars. $35/each. Send me a PM to discuss purchasing.

Posted by: ericread Feb 17 2010, 05:19 PM

I purchased and installed the new TPS, but I'l having some difficulty in adjustment. Using the following adjustment guide, I tried to perform as directed:

Attached Image

But I just can't seem to get the Ohm Meter to go to zero.

Now, please take a look at my TPS:

Attached Image

Should the wires "C" between post "A" and post "B" always short between these posts, or is there an offset where the wire only either contacts post "A" or post "B", but never both at the same time?

In looking at my TPS, can you see anything else which my be causing my problems?

I drive a 1974 2.0L stock FI engine.

My thanks in advance.

Eric Read

Posted by: davesprinkle Feb 17 2010, 10:52 PM

QUOTE(ericread @ Feb 17 2010, 03:19 PM) *

I purchased and installed the new TPS, but I'l having some difficulty in adjustment. Using the following adjustment guide, I tried to perform as directed:

Attached Image

But I just can't seem to get the Ohm Meter to go to zero.

Now, please take a look at my TPS:

Attached Image

Should the wires "C" between post "A" and post "B" always short between these posts, or is there an offset where the wire only either contacts post "A" or post "B", but never both at the same time?

In looking at my TPS, can you see anything else which my be causing my problems?

I drive a 1974 2.0L stock FI engine.

My thanks in advance.

Eric Read

Eric, the switch is designed with hysteresis (backlash) so that contact C is shorted either to post A OR to post B, but never to both simultaneously. In this way, the ECU can detect an opening throttle vs. a closing throttle.

But here is the problem with your TPS -- you've got a 2.0 liter board mounted in a 1.7 liter sensor plate. The 1.7 liter throttle rotates the opposite direction, so your mismatched sensor will never detect idle.

Posted by: ericread Feb 18 2010, 08:41 AM

QUOTE(davesprinkle @ Feb 17 2010, 08:52 PM) *


Eric, the switch is designed with hysteresis (backlash) so that contact C is shorted either to post A OR to post B, but never to both simultaneously. In this way, the ECU can detect an opening throttle vs. a closing throttle.

But here is the problem with your TPS -- you've got a 2.0 liter board mounted in a 1.7 liter sensor plate. The 1.7 liter throttle rotates the opposite direction, so your mismatched sensor will never detect idle.


That would make sense. Thanks!

Eric

Posted by: hushpuppy Sep 21 2018, 06:57 PM

dave,
do you still have any of the boards left 75 2.0 thanks,

Posted by: jagalyn Sep 26 2018, 08:17 PM

QUOTE(hushpuppy @ Sep 21 2018, 04:57 PM) *

dave,
do you still have any of the boards left 75 2.0 thanks,



https://900designs.zoeysite.com/index.php/catalog/product/view/id/2516/s/2-0-l-throttle-position-sensor-board/

Posted by: worn Sep 27 2018, 01:28 AM

QUOTE(r_towle @ Jun 15 2009, 04:11 PM) *

Isnt that gold?
Could gold leafbe applied tofix the groove?
Even silver solder might work?

Rich

Good idea, but gold leaf is generally applied with some varnish as glue. Conduction might be a problem. True silver solder melts at a temp that would vaporize the board. Plating is certainly an option as long as you hav3 a thin film of metal to go on. I have used cars well products a lot and they offer gold and silver kits. Hmmm.

Whoops. Thought they we’re gone because I didn’t check the dates of the posts.

Posted by: Tbrown4x4 Sep 27 2018, 02:44 AM

914Rubber has the boards in stock.

Oops. I didn't see jagalyn's link.

Posted by: ChrisFoley Sep 27 2018, 06:37 AM

QUOTE(jagalyn @ Sep 26 2018, 10:17 PM) *

QUOTE(hushpuppy @ Sep 21 2018, 04:57 PM) *

dave,
do you still have any of the boards left 75 2.0 thanks,



https://900designs.zoeysite.com/index.php/catalog/product/view/id/2516/s/2-0-l-throttle-position-sensor-board/

So why does the part listing for a 2.0L TPS board have a description for a 1.7L car?

Posted by: jagalyn Sep 27 2018, 07:14 AM

https://shop.914rubber.com/Porsche-914-Throttle-position-sensor-board-20-914TPS20.htm?categoryId=-1

https://www.ebay.com/itm/Porsche-2-0-Throttle-position-sensor-replacement-board-914-Rubber-Brand/382557818406?hash=item5912390e26:g:l-YAAOSwSdFZe6Om

Posted by: Mikey914 Sep 29 2018, 10:31 PM

QUOTE(ChrisFoley @ Sep 27 2018, 05:37 AM) *

QUOTE(jagalyn @ Sep 26 2018, 10:17 PM) *

QUOTE(hushpuppy @ Sep 21 2018, 04:57 PM) *

dave,
do you still have any of the boards left 75 2.0 thanks,



https://900designs.zoeysite.com/index.php/catalog/product/view/id/2516/s/2-0-l-throttle-position-sensor-board/

So why does the part listing for a 2.0L TPS board have a description for a 1.7L car?

Because we screwed the pooch. Sorry about that. It is indeed for the 2.0. We will get that fixed.
Thx
Mark

Posted by: davesprinkle Sep 30 2018, 01:11 AM

QUOTE(hushpuppy @ Sep 21 2018, 05:57 PM) *

dave,
do you still have any of the boards left 75 2.0 thanks,

Yes, I've still got boards available for the late 1.7 liter cars and for the 2.0 liter cars. You can PM me if you're interested.

I'm aware that 914rubber is also manufacturing these.

Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)