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KTPhil 
Samba Member
Joined: April 06, 2006
Posts: 36154
Location: Conejo Valley, CA
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 Posted: Wed Sep 10, 2025 12:40 pm Post subject: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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Of all sources... would you believe VESPA?!
I can't swear the temp range and values are identical, but some report having success using this part.
I like the connector instead of the Bosch pigtail, since it lets you use a regular socket.
Plus the brass may not corrode as quickly.
And a steal at $20 shipped!
https://www.scooterwest.com/cylinder-head-temperat...RDa9Sf8o97
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback
Last edited by KTPhil on Wed Sep 10, 2025 3:45 pm; edited 1 time in total |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23309
Location: Oklahoma City
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| Posted: Wed Sep 10, 2025 3:30 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet |
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| KTPhil wrote: |
Of all sources... would you believe VESPA?!
I can't swear the temp range and values are identical, but some report having success using this part.
I like the connector instead of the Bosch pigtail, since it lets you use a regular socket.
Plus the brass may not corrode as quickly.
And a steal at $20 shipped!
https://www.scooterwest.com/cylinder-head-temperat...RDa9Sf8o97
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Actually....that should work. It may not be spot on when in the middle ranges between cold and fully warmed up....but at cold and warmed up it should work fine.
This site has the values in C°.
https://www.pedparts.co.uk/product/505/piaggio-eng...85adf_qYki
It's negative coefficient so it's workable.
68°F= 2500 ohm
104°F = 1300 ohm
167°F = 380 ohm
212°F= 100 ohm
There is a question as to how much the resistance rises as it gets colder than 68° and how m7ch it drops when it gets over 212°.
Ray |
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Sun Sep 21, 2025 12:59 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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I just ordered two of these.
Has anyone tried this in any VW FI application? And if so, how many miles?
The Bus Depot one I put in lasted about 5k miles when it failed on our way home from a weekend getaway today. I had an old one that had been rattling around in my tool box for 20 years....it's had tools thrown on it, sure it was rained on several times. Put it in, and the bus ran great...idles better now than it has since I put the engine in 4k miles ago. I had another used spare (bus depot) and I've got another new one in a box at home. Like everyone else, tired of these things failing. Suppose I could put a potentiometer in it, and manually adjust, but it would be nice to find one that works.
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1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Mon Sep 29, 2025 4:56 am Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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I received the Vespa temp sensors in the mail yesterday and installed them that evening. Took it for a test drive, and around town it was ok, but hard acceleration or cruising above 55 mph caused bucking. Might have been able to dial it out with the AFM, but not that desperate yet.
I used thicker wire (believe it was 14 or 16 gauge) for the pigtail than was expected, not sure if that would have impacted my results vs using something like 20 or 22 gauge.
I might try a thinner gauge pigtail, but right now, I would say my initial reaction is that this won't work for buses.
_________________
1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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KTPhil
Samba Member
Joined: April 06, 2006
Posts: 36154
Location: Conejo Valley, CA
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| Posted: Mon Sep 29, 2025 9:35 am Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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It's just a resistor. It happens to vary over temperature. At the lowest resistance (hottest), the ECU doesn't weigh the reading much, so I doubt it is the source of your bucking. In the few cases where the hot resistance gave too much leaning, a fixed-value resistor has been spliced in series to bias it up a bit.
_________________
Current Fleet:
- '71 Fastback
- '69 Westfalia
Retired:
- '67 Beetle
- '65 Beetle (x2)
- '65 Bus
- '71 Squareback |
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Mon Sep 29, 2025 11:26 am Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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| KTPhil wrote: |
| ........ In the few cases where the hot resistance gave too much leaning, a fixed-value resistor has been spliced in series to bias it up a bit. |
Are you implying that this is what some folks did to get it to work properly in a VW application? If so, what was the value of the resistor?
It was working fine with the TSII that was in there; this is the only variable that I changed. Although possible, I think it's unlikely that there was another cause for the bucking.
_________________
1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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KTPhil
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Joined: April 06, 2006
Posts: 36154
Location: Conejo Valley, CA
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Mon Sep 29, 2025 2:01 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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These are some excellent discussions on the TSII, and how it works (I've previously read all of them as I've headed down my TSII journey). Thanks for putting them all in one place..that is handy. You also reminded me of the "DIY" ones available in the classifieds....might have to give them a shot.
I was hoping that the Vespa would be a 'plug and play' replacement, but this does not seem to be the case. Granted, I'm just one data point. I was also hoping that other people would have chimed in with their experiences with the Vespa TSII when I made my initial post the previous weekend.
_________________
1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 23309
Location: Oklahoma City
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| Posted: Mon Sep 29, 2025 3:04 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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| TrollFromDownBelow wrote: |
These are some excellent discussions on the TSII, and how it works (I've previously read all of them as I've headed down my TSII journey). Thanks for putting them all in one place..that is handy. You also reminded me of the "DIY" ones available in the classifieds....might have to give them a shot.
I was hoping that the Vespa would be a 'plug and play' replacement, but this does not seem to be the case. Granted, I'm just one data point. I was also hoping that other people would have chimed in with their experiences with the Vespa TSII when I made my initial post the previous weekend. |
Well, put it back in...drive until it's fully warmed up. Stop the car and take your voltmeter and measure the resistance of it. Compare to the book.
Then put your original TS-2 back in and repeat.
If it's too low, add an inline resistor. If it's too high....it may not work for you. Ray |
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Tue Sep 30, 2025 4:27 am Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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I get it....yes, I could make the Vespa TSII work. I was hoping for an alternative to the Uro brand that is functional out of the box, but fails after 4k miles.
Maybe asking for a TSII that functions correctly and lasts longer than the life of a fishfly is asking too much.  . Push comes to shove, I can install a potentiometer.
_________________
1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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tjmartin317
Samba Member
Joined: March 18, 2022
Posts: 290
Location: West Virginia
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| Posted: Fri Oct 03, 2025 6:55 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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| Push comes to shove, I can install a potentiometer. |
That's what I did! With a toothpick!
But I would absolutely love it if I didn't have to do this anymore and the car just worked! I'm going to order one of these and give it a try. Been fighting with high idle and timing though, so there are a few other issues to work through first. |
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TrollFromDownBelow
Samba Member
Joined: January 04, 2005
Posts: 439
Location: VA Beach
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| Posted: Wed Oct 08, 2025 4:15 pm Post subject: Re: Alternate part for head temp sensor TS2 on D-jet (& L-jet) |
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Steve (the supplier) said he hasn't had one fail yet. Mine is supposed to deliver on Friday, take it camping next weekend. We'll see how it works.
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1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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