[T3] TB info?

Jim Adney jadney at vwtype3.org
Sat Mar 12 14:32:33 PST 2022


On 12 Mar 2022 at 10:43, Max Welton wrote:

> You all may recall that I'm using Megasquirt so I need a three-wire TPS
> and a IAT sensor.

The ONLY 3-wire TPS I've ever seen was a photo in one of the early Bosch 
or VW manuals. AFAIK, that version never made it into production. I don't 
know the pinout of the 4-wire version off hand, but you can figure it out 
easily if you remove the cover.

The 2-wire TPS has common and a switch that closes at idle.

The 4-wire has the 2-wire bits, plus 2 interdigitated contacts that connect 
alternately to common as a kind of throttle enhancer at the onset of 
acceleration, like a throttle pump.

The 5-wire is the same as the 4-wire, plus the addition of a switch to 
common that closes on full throttle.

The 2-wire TPS fits on a smaller diameter throttle shaft. It won't mount on the 
later IADs.

The 4 and 5-wier TPSs fit on a larger diameter throttle shaft. They can 
interchange, but they won't fit on the early '68-9 IADs.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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