I'm pretty sure that at it's lowest setting, my Mustang TPS was measuring .39 between yellow and red wires...but I'm not 100% sure

 

im aware that its a linier pot, but most pots are logrithmic. where can i get a linier pot?

this pot reads 570ohms at idle. whats the easiest way to calculate z?

 

FWIW, I recall that mine was .38v at idle and the car ran well. I think the spec is .32v to .36v.

Cheers
DD

 

where did you guys get yours? mine is BWD from advance auto.

 

hang on, I'll look it up and find out.
Just a thought, what happens when you disconnect the CTS when your engine is running?

 

Tru-Tech TH59T Throttle Position Sensor $22.03 from Amazon.

 

Most pots are Linear - Volume controls are log because thats how our ears work.

Z is the easy symbol for Ohms.

If you give me the ohms measurements I can design a circuit that should work. I can not test it as my cat is sitting there with the engine supported by a railway sleeper.

I need resistance values for
Yellow to green
yellow to red idle
yellow to red wot

 

HEY, warren ,, whats a railway sleeper?? pic

 

You can see the large chunk of wood under the car holding the engine up, this pic was taken just before I removed the engine cross brace.

The railway sleeper is what they put under rail tracks these ones are old the new ones here are concrete so I guess the next generation will not be using them.

 

When I measure my original TPS ( which needs replacement ) I'm showing high resistance between red and green at "idle" position and about 40 "Ohms" at full. You're saying it should be a 6K "Ohm" potentiometer between the outsides? So, it looks as though I can get myself a good pot from Mouser ( Bourns ) and that should solve my problem. Being that you're referencing the Yellow lead and not the red, I should be reading low ohms at idle and high at full throttle between the wiper and yellow right? BTW, this is on my '85 XJS. I don't know if they use a different value or not on the '89 as that's when they went with the Mirelli. When I first measured before taking it apart, I was getting 220K "Ohms" between the two ends of it ( yel and green ). You're referencing "Z" as impedance, which is usually reserved for AC circuit measurements.

 

Also, are you making those measurements ( on your ohms ) in circuit or with the pot unplugged at the pot itself? I'm only asking in order to provide the correct value pot. I can make the mustang pot work if it's somewhere around the same value between the two outside pins.

 

My pot is broken on the yellow side, so I'm unable to reference to yellow...That's why my previously mentioned values are referenced to green. That occurred after I took it apart and attempted to clean it.

 

After taking my pot apart and reading the resistance trace, it looks as though it's a log taper, not linear. If this is the case, they may have designed it that way so it will have high delta ( variance ) at the low end for better throttle response. Sort of like putting lighter springs in the distributor to get more power on tap at start off. Even though my pot is defective, I was able to garner that info, but it would have to be in pretty bad shape to show log taper if it was supposed to be linear.