Lone Ranger

I checked voltage on my TPS. With the TPS installed, manually moving the throttle all the way to the mechanical stop for WOT position (move throttle by hand at the throttle body housing not by gas pedal) gives me only a reading of approx. 3.75 volts. NOW, removing the TPS and using a screw driver to manually rotate the TPS full travel to the stop yields approx. 4.7 volts. So the TPS is producing 4.7v fully rotated, but when installed for some reason the throttle body arm does not rotate it far enough when the throttle body arm is at WOT position. I checked the position of the throttle body plates at WOT with the rubber accordian air intake duct removed and they are all the way down flat at WOT as they should be.

Is my only option to buy one of the after market TPS's that allow the voltage output to be adjusted? The stock TPS does not have the slotted screw holes for adjustment like some previous models did, it cannot be moved to compensate once it is installed.



[Modified by Lone Ranger, 8:48 AM 6/18/2002]

Lone Ranger

Anyone? Just need to know, 3.75 volt TPS signal won't be read by ECM as Wide Open Throttle will it? What are my options?

Red94Vette

I will check my data log when I get home but I think mine reads 100% WOT at high 3s.

Lone Ranger

Is 3.75v enough to signal WOT on your '94?

C4TOMCAT

all I did was elongate the slots to get the position needed. might want to try that first before doing any $$$ items. hope it helps.

VMAX451

I just checked some scan logs that I have, and I found one where 3.74 volts was registering as WOT. 3.46 was showing 97% (wide open = 99% on my scanner). This is on a '92, not sure if it's different on a '95.

My stock TB, fully open, was hitting only 3.88. An aftermarket TB with the same TPS hits low 4's, FWIW. I'd guess you are ok IF (big IF) you are also getting 3.75 when you use the gas pedal rather than hand opening the throttle.

95AquaC4

For some reason I remember my 95 reading nearly 6 volts at WOT. Something like 5.62, or something like that. I will research a bit, and get back here.

95AquaC4

Ok..did my research...here it is. .5 volts at idle to 4.5-5 volts at WOT. I adjusted above this, but this the actual settings. 3.75 is too low.

Red94Vette

checked over some of my logs on my 94.

3.63 reads 100% WOT

My full throttle is 3.92 volts but 3.63 read 100% during a shift on a run.

For you to know 100% you would need a cable and laptop and gather data. If you are serious about modding I would do this.

95AquaC4

Are these #'s too low? My book says 4.5 to 5 for PCM to enter open loop mode. Now I'm confused.

Lone Ranger

Tomorrow after work I'm going to try elongating the screw holes on the TPS to see if I can rotate it somewhat to get closer to being at least over 4 volts at WOT position on the TB blades. If that doesn't work I may shoot the lock off my wallet and get one of the adjustible voltage TPS's.

VMAX451

Just be sure that your idle voltage is within spec after you do this. Usually you try to set the voltage at the idle end and the top end takes care of itself, but it's worth a try. There is a self calibration at start up, so if it's really out of whack at idle you would get a code.

Lone Ranger

Is 0.68 volts the maximum you can go on idle voltage before it will throw a code?

Lone Ranger

I have a brand spankin' new laptop, but no cable and no software. Is the software expensive and hard to learn? How much for a cable and where?

BTW, I ovalled out the screw holes in the TPS tonight, was able to get it to ~ 0.6v idle and ~ 3.9v WOT. I am using an analog voltmeter, wish I had bought a digital last year when I got one.

But now you got me wantin' to fully analyze it while driving. Good use for my new Compaq laptop :yesnod:


[Modified by Lone Ranger, 8:01 PM 6/20/2002]