[T3] 72 FI

[Dennis Stiefel]

> Wondering if anyone here can fill me in on how the late model TPS works on
the say 72 FI system.
> Does it function in much the same way as modern TPS or is it way
different?

I THOUGHT modern TPS units contained a variable resistor, so that they could
tell the brain exactly where they were at any moment. Our TPSs only give
actual position information at idle, and, for '72-3 only, wide open throttle
(WOT.)

For '68-9 the TPS only tells when the throttle is closed.

For '70-1 our TPS indicates idle and has extra contacts that show that the
throttle is opening (but not how far open it is.)

For '72-3 our TPS adds the WOT contact.

Other than the idle and WOT contacts, none of them show actual position.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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The TPS on modern cars dose tell the computer a percentage of how far the
throttle is open.  For example most modern cars with automatic trans needs
this info to compare with vehicle speed and other things to know when to
change gears and lock the torque converter among other things so it must
know an exact percentage of that.  I thought the 72-3 done this. Why do they
need 5 pens just to know idle and WOT position. My son's 88 golf's digifant
II TPS just dose idle and WOT but is a lot different than the one on our FB.

Dennis Stiefel
72 Fastback FI MT