[Gmecm] TPS Question for a 1986 Grand National

[Darryl M Gilbert]

Hello: On your TPS sensor. Having taken a bad one apart to see how it
ticks this is how it goes. This is the standard 87 vintage TPS used on I
guess most GM cars. It has 3 terminals. Inside are two resistors in
series sort of .One resistor is 2.5k and the other is 5.5 k give or take
the accuracy of stuff. The center pin goes to one end of the 2.5 k
resistor, the other end goes no where. One outside pin goes to one end of
a 5.5k resistor and the other outside pin goes to the other end of the 5k
resistor. So from outside pin to outside pin i would expect to see 5.5k
there abouts. These two resistors are laying side by side on a plastic
substrate, with  trifurcated contacts on a shorting bar running on each
one as they lay side by side. Think of a slide on a steel guitar as it
runs up and down the strings, thats the way to look at this mess. These
use a lot of rivet contact technology which is as old as the hills and
where a lot of the problems lie with junk built like this. What i mean by
rivet technology is there is no thru plated holes connecting through the
plastic substrate to the other side where a printed wire may lie. The
rivet gets a little crud and the resistance climbs or opens all the way.
There are 6 of this great technology rivets used to manufacture this
thing. This also makes it prone to vibration and heat, the rivets expand
or wiggle and make and break the circuit inside the TPS, neat huh? I hope
that helps you somewhat. Thats the way I remember it, i may even have a
schematic of it if i can locate it
good luck
Darryl...
On Wed, 3 Aug 2005 11:01:46 -0400 "Fred Carrado Jr." <fredc at moroso.com>
writes:
> Greetings  Everyone,
> 
>  The TPS on a Buick Grand Nation . Does any one know what value 
> resistance
> that is ?  Is there any resistor in series with wiper lead?
> 
>  The reason why I ask is becasue , I'm working on a project for my 
> self . I
> know the ECU is looking for ~ .40  to < 4.5 volts .
> 
>  But when I do a resistance check I get the following:
> 
>  At the idle posistion:
> 
> A to B = 5.98K ohms
> B to C = 2.5 K  ohms
> A to B =  4.14K ohms
> 
> 
> In the WOT position :
> 
>  A to B = 2.5 K ohms
>  B to C = 5.7K ohms
>  A to C =4.15 K ohms
> 
> 
>  This is measure in the car ,engine off and the wire harness 
> unplugged , So
> I am directly across the sensor it self.
> 
>  Is there a 2 K resistor in series with the wiper lead ?
>  Or is the internal pot a 20 K with a 5K resistor in parallel with  
> A & B ?
> 
> 
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