[Gmecm] TPS Question for a 1986 Grand National

[Fred Carrado Jr.]

OK, Now this makes sense.

 I Agree with you on the rivet fastening . Most like done for cost not
reliability .

 Thank you , very much . This is big help.

----- Original Message ----- 
From: "Darryl M Gilbert" <dgilbert78 at juno.com>
To: <gmecm at diy-efi.org>
Sent: Wednesday, August 03, 2005 12:38 PM
Subject: Re: [Gmecm] TPS Question for a 1986 Grand National


> 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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> >
> >
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