TPS failures - better designs?

[Roger Heflin]

On Thu, 2 Dec 1999, Peter Gargano wrote:

> Dear EFI gurus,
> 
> I was at the wreckers (bone yard?) yesterday. Seems
> that the Throttle Position Sensor is a common point
> of failure. Being a novice when it comes to GM EFI 
> hardware, I figured that a better design than a simple
> pot (potentiometer, or "variable resistor") was in 
> order. Having recently played with a Hall Effect sensor,
> for ignition pickup, I also figured that a simple TPS,
> both reliable and robust, could be done cheaply and 
> easily with just such a Hall Effect device.
> 
> As we all know, "there's nothing new under the sun"...
> So, here's the EFI content:
> 
>   Are there any Hall effect TPS sensors around?
> 
> Or, perhaps a better question is:
> 
>   Are there more reliable TP sensors than simple pots?
> 

Hall effect requires motion, so it would not give you a reading at a
constant position.  Even if you did count the changes and keep track
of things after a while the inaccuracies would add up and the TPS
could be quite a bit off of what it really is.

A coil with a piece of metal in it, where the metal is pushed/pulled
in/out of the coil would probably work, the inductance of the coil
will change depending on how far the metal is in the coil.  I believe
the old electronic digital scales used this to measure the amount of
deflection of the spring and by the deflection determined weight.  The
newer ones may do this do.

			Roger