# throttle position sensor



## oldkayaker (Nov 22, 2006)

I have a 1991 Jetta with the Digifant 1 fuel injection system. I was having idle problems and hesitation coming off idle. I checked the OBD. It said I had a problem with my throttle position sensor and, sure enough, when I pulled it out and disassembled, the carbon tracks on the potentiometer were worn away. This TPS is pick'n'pull replacement. I don't have too much hope of finding another due to the scarcity of these old cars today or the possibility of it having much life left, too. Does anybody know a source of a new or rebuilt TPS? Or know of a possible swap from another make? I know that there may be some modification needed to mate the throttle shaft to the TPS. Any ideas?

Thanks


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## Rabbitissimo (Dec 21, 2009)

I am building a car up right now and I just happen to have a throttle body with a TPS.
Date stamped 89.
I will not be using the switch because I will be mounting a wide open throttle switch up top instead.
My car has a manual transmission. 
Check out my build it has pics of this TB, and I'm sure I could figure out how to remove the TPS and still have it operate properly.
PM me, let me know if it is what you need... 
~Rabbitissimo


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## Svedka (Jul 4, 2008)

oldkayaker said:


> I have a 1991 Jetta with the Digifant 1 fuel injection system. I was having idle problems and hesitation coming off idle. I checked the OBD. It said I had a problem with my throttle position sensor and, sure enough, when I pulled it out and disassembled, the carbon tracks on the potentiometer were worn away. This TPS is pick'n'pull replacement. I don't have too much hope of finding another due to the scarcity of these old cars today or the possibility of it having much life left, too. Does anybody know a source of a new or rebuilt TPS? Or know of a possible swap from another make? I know that there may be some modification needed to mate the throttle shaft to the TPS. Any ideas?
> 
> Thanks


You have a very special TPS if your car is a 8v digi 1 it is more than likely the super small TPS so it fits above the fuel rail behind the head the factory 16v tps does not fit it is to tall and hits the fuel rail, as for a replacement part you must go to VW dealer because the digi 1 system that came in the mk2 was designed for cali emissions and not very many were made it is a very expensive part to buy new I would post a WTB classifieds and post a pic of the throttle body with TPS attached asking if anyone has one for sale.


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## oldkayaker (Nov 22, 2006)

Digifant 1 doesn't have the closed and wide open throttle switch on the throttle body like the other digifant systems. It's a potentiometer set up to providing a signal of variable voltage (0.5 to 4.5 volts) to the ECU. This throttle position sensor was only used on the California models, I believe, and which adds to its relative scarcity. Thanks for the offer, though. It's nice to hear that there others working to keep these cars on the road.

rob


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## oldkayaker (Nov 22, 2006)

I've already checked with my dealer and they say the Digifant 1 TPS is NLA. I'm taking a chance by buying a BMW TPS which looks to be of similar dimensions and hoping I can modify or kludge the connection between the throttle shaft and the TPS to work. And hoping that the resistance values are comparable, too. I'm guessing that the Digifant 1 system which was a VW licensed variation of the early Bosch Motronic would have similar operating signals from the sensors.

rob


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## Svedka (Jul 4, 2008)

I have one of the digi 1 throttle bodys with a good tps pm me if the bmw one dont work out


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## oldkayaker (Nov 22, 2006)

*final solution*

I bought a new throttle position sensor for a 93 Jetta (037 907 385Q). I filed down the shaft on the throttle body to mate with the new sensor. I checked the resistance values throughout the range of movement of the butterfly valve and it matched the values of the previous sensor I had installed when I first acquired it from my local pick'n'pull. To accommodate the new throttle position sensor and upgrade my fuel system, I installed an aluminum fuel rail with a remote fuel pressure regulator. So far, it's working great.


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## ziddey (Apr 16, 2006)

if the bmw sensor doesn't pan out, you can always try posting in the california regional section here. obviously, digi1 8v tps's are quite common in california junkyards.


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