TPS Voltage

M

Maddawg03

Member
I finally have my 92 back in the garage and have been getting reaquainted with it. Just for the sake of education, I checked the TPS Voltage today and found that I was at 0.41V at 0 throttle and it maxes out at 3.98V manually moving the throttle lever on the throttle body and 3.82V if I floor the pedal. I adjusted the 0 throttle voltage to 0.54V to be within spec. But I can't see any way to change the max voltage.

My question is at what point does the computer sense WOT. Everything I see online indicates 4.0V is the WOT threshold. Would 3.98V indicate a problem with the TPS, and is there an adjustment procedure for the throttle cable to get the remaining 0.16V that I lose when actuating the throttle via the pedal?

Thanks,
Maddawg03
 
IT sounds like your dealing with a defective TPS sensor, there's two basic replacements, the non-adjustable and adjustable versions of the switch/sensor as long as tps sensor is set at .054 volts at idle the difference between 3.9 volts and 4 volts at most is all but insignificant to the computer under most start and cruise conditions) as it takes much of its injector pulse compensation info from the other sensors output,(BTW it is supposed to max out at 5 volts not 4 volts) like the coolant temp, o2 sensors and MAT (MAF sensors) sensors on some years (1985-91)
first check your shop manual for the fuse and fuse able link locations
fuses are located in several locations and fuse-able links near the battery

but it may not run to its full potential so swapping to a new TPS might be a good idea!
are you pulling any trouble codes?
tps4.jpg

btw an adjustable fuel pressure regulator can help tune here
the info in these threads should help

viewtopic.php?f=32&t=304

posting.php?mode=edit&f=80&p=1025

viewtopic.php?f=32&t=596

http://www.ecklers.com/product.asp?pf_i ... pt_id=1306

" *

http://www.thirdgen.org/tpimod2

The TPS (throttle position sensor) is a variable resistor connected to the throttle shaft on the throttle body. When the accelerator pedal moves, the TPS sends a signal to the computer. The computer calculates the fuel delivery and the air being consumed based on the throttle valve angle. Our adjustable TPS lets you fine-tune your Corvette's throttle response for maximum performance by changing the voltage of the sensor. The stock TPS is preset and cannot be adjusted. Out-of-adjustment TPS's can cause erratic idle, stumbling, surging and overall poor engine performance. This TPS kit includes the sensor, replacement connector/terminals, test jumper adjustment tool and instructions. "

http://www.ecklerscorvette.com/corvette ... -1996.html
 
Well I replaced the sensor and I still see 3.98 volts. I verified the 5V reference wire so I'm pretty sure wiring is good. It appears the throttle lever (Not sure if that is the right term) hits the stop on the throttle body before the sensor swings enough to reach greater than 4 volts. I did hook up my data logging software, and the car is seeing 100% throttle with the pedal floored so this may not be the issue I thought it was. Now I'm just curious why I don't see more than 4 volts.

The car does seem to accelerate smoother with the new sensor however, not sure if it's just perception or reality though.
 
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