North American Turbocoupe Organization



TPS flat spots
RDOG Offline
Posting Freak
#1
I have a 92 supercoupe 60mm TB, and I need to check my TPS for flat spots. What am I looking for EXACTLY. A sudden zero/null reading?

Where does that flat spot typically occur? WOT?
1986 Turbo Coupe. Boport StageIII head, Boport 2.1, Performance Techniques 50 trim hybird, StageII.63, stinger 3" exhaust, Phenolic spacer, Boglog header,NPR FMIC intercooler setup, kirban fpr, bigrmotorsports fuel rail, diablo water meth kit, CAI, remote mount TFI, CHE rear adj control arms, MAC girdle, 8.8 rear disc, aluminum drive shaft, H&R lowerings springs Tbird Turbo Specific, y MAS!!
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86 XR7 5spd Offline
Senior Member
#2
this troubleshoot is easier with an analog VOM,
because what you are looking for is:
a smooth and linear change in resistance across the TPS as you cycle it from closed -> open,
and back, open -> closed

(this presumes you have disconnected the TPS and are measuring 'resistance' across it's terminals;
if TPS is connected with power on,
you would expect a linear voltage change from near 0 to near 5 volts)

IIRC one pin (when referenced to ground 3rd pin) will go from high resistance -> 0,
while the second pin (ref'd to ground) will go from 0 -> high resistance...

check em both just to make sure Smile
David T
T5 / ported E3 / .63 / 35# / K&N
2.5" exhaust w/ cherry bomb
30+ mpg! 8.2 0-60, 16.4@88 1/4 (gTech)
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zip Offline
Member
#3
Quote:Originally posted by RDOG:
I have a 92 supercoupe 60mm TB, and I need to check my TPS for flat spots. What am I looking for EXACTLY. A sudden zero/null reading?

Where does that flat spot typically occur? WOT?
You will look for zero readings when checking the voltage between the output and ground on the TPS. Like said above its easier to see the dead spots with an analog meter. On my TPS the dead spot was early in the sweep, around 1.8V if I remember correctly.
Matt
86 TC 5spd:QH/SD,Walbro190,CFI 52#, AFPR,WB,FMIC,3"dp to axle, .63 T3, E6,Stock Longblock.
Shelf:N/A 2.3, Die grinder, Carbide Burrs.
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RDOG Offline
Posting Freak
#4
Quote:Originally posted by zip:
Quote:Originally posted by RDOG:
[b] I have a 92 supercoupe 60mm TB, and I need to check my TPS for flat spots. What am I looking for EXACTLY. A sudden zero/null reading?

Where does that flat spot typically occur? WOT?
You will look for zero readings when checking the voltage between the output and ground on the TPS. Like said above its easier to see the dead spots with an analog meter. On my TPS the dead spot was early in the sweep, around 1.8V if I remember correctly. [/b]
When you found the problem, did you just replace the bad unit or was there a problem with the TB itself?
1986 Turbo Coupe. Boport StageIII head, Boport 2.1, Performance Techniques 50 trim hybird, StageII.63, stinger 3" exhaust, Phenolic spacer, Boglog header,NPR FMIC intercooler setup, kirban fpr, bigrmotorsports fuel rail, diablo water meth kit, CAI, remote mount TFI, CHE rear adj control arms, MAC girdle, 8.8 rear disc, aluminum drive shaft, H&R lowerings springs Tbird Turbo Specific, y MAS!!
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84TBirdTurbo42 Offline
Senior Member
#5
its an issue with the sensor, not the tb.
Chris Perry
1984 Ford Thunderbird Turbo Coupe. Dead, NY rot killed her
1986 Thunderbird shell, swapping parts from the 84.
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TurboCoupe50 Offline
Posting Freak
#6
It's best to use the voltage method...

With the meter positive connected to the TPS green wire and neg on ground check for a smooth voltage climb as you open the throttle... Any dip or drop out in voltage indicates a worn TPS...

NOTE when setting TPS voltage use the black wire on the sensor for ground, using the engine as ground may give a slightly different reading... A small voltage difference because of ground is not important when checking the TPS for dead spots...
1988 Turbo Coupe331 AOD

1972 Comet GT

1969 Fairlane Cobra 428CJ 4-Speed
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zip Offline
Member
#7
Quote:Originally posted by RDOG:
When you found the problem, did you just replace the bad unit or was there a problem with the TB itself?
It was a issue with my sensor. After replacement all was well.
Matt
86 TC 5spd:QH/SD,Walbro190,CFI 52#, AFPR,WB,FMIC,3"dp to axle, .63 T3, E6,Stock Longblock.
Shelf:N/A 2.3, Die grinder, Carbide Burrs.
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RDOG Offline
Posting Freak
#8
Checked out my NONADUSTABLE TPS, and it was at .86. I read that its supposed to be at .90-.95 for best results. I set it to .92 because thats the best I could do by drilling the TPS holes slightly larger.

Is that OK?
1986 Turbo Coupe. Boport StageIII head, Boport 2.1, Performance Techniques 50 trim hybird, StageII.63, stinger 3" exhaust, Phenolic spacer, Boglog header,NPR FMIC intercooler setup, kirban fpr, bigrmotorsports fuel rail, diablo water meth kit, CAI, remote mount TFI, CHE rear adj control arms, MAC girdle, 8.8 rear disc, aluminum drive shaft, H&R lowerings springs Tbird Turbo Specific, y MAS!!
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84TBirdTurbo42 Offline
Senior Member
#9
if your within spec, which you are, then your good. As long as there's no dead spots in the TPS. you should be fine. There is often a little wiggle room with sensors, because not every sensor is going to be perfect.
Chris Perry
1984 Ford Thunderbird Turbo Coupe. Dead, NY rot killed her
1986 Thunderbird shell, swapping parts from the 84.
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RDOG Offline
Posting Freak
#10
Out of curiosity, what happens if you are out of spec, for instance me being at only .86?
1986 Turbo Coupe. Boport StageIII head, Boport 2.1, Performance Techniques 50 trim hybird, StageII.63, stinger 3" exhaust, Phenolic spacer, Boglog header,NPR FMIC intercooler setup, kirban fpr, bigrmotorsports fuel rail, diablo water meth kit, CAI, remote mount TFI, CHE rear adj control arms, MAC girdle, 8.8 rear disc, aluminum drive shaft, H&R lowerings springs Tbird Turbo Specific, y MAS!!
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