Today while installing my Snow Performance system, I spent several hours trying to figure out why my signal was 3V until i realized it was in hertz when I switched over my meter. I decided there has to be another way to tap into a 0-5V source. I turned on my SCT tuner and started playing with the gauges to see what they had to offer and I found a throttle pedal voltage. The voltage is 0-5v i though to my self what if i were to tap into this. I set this up on the gauges and found i was only getting 4V. If i press really hard it moves to 4.37v. So im only utilizing 80% of my throttle and 87 if I really try.
My question is this, Is this a proportional valve meaning even though this is 80% the throttle body will be 100%. Is there a way to verify this? It doesn't seem logical if i can squeak an extra 7% because that would put my throttle at 109%(for those who are confused Current reading/Max range = percentage. 4.37/4 = 1.0925 = 109.25%) and either the throttle body would go out or the computer would compensate for this and I would actually lose throttle response because my pedal range increased.
If this number is true to the throttle body is there a way to adjust or modify the pedal to receive my full 5V that anyone knows of? I looked on other forums and found a few things in chevy where people were saying 75 to 80% is normal but give no response as to why. I have also tried to utilize the pedal reset mod but didn't yield any noticeable performance I'm presuming because of my truck being already programmed. In my field of work 87% of the inlet valve would not be enough to do the job.

Also on a side note. I decided it was a bad idea to tap into here because the computer wouldn't be at the same response level as my foot. I decided to look for something closer to the throttle body. I gave up for the night and found a PDF from nitrous express for a 5.0 coyote plate system installation instructions. Page 6 shows a diagram using the TPS wire either green/violet or brown. Just an FYI for anyone installing a meth system.

 

That 5v you are talking about is merely a reference voltage, the pcm uses it as a base line for operation.
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These vehicles are drive by wire. The relative pedal position does not necessarily mean you are getting the same rotation of the throttle body. These vehicles will close throttle for torque reductions and such. You could have your pedal to the floor and if you logged your throttle angle actual, it would vary up and down throughout the RPM's. Its just how these vehicles are.

Also, it is normal for your pedal position to not reach 5v.
.6 to 1.0v is going to be idle
Add .4-.6 above the idle voltage for cruising
and add 2.7-3.5v for WOT.

 

It may be normal but is the throttle body actually achieving 100%?

The equipment I work on is very similar in function. When I open my inlet valve 100% I can verify it is open 100%. The unit will then fluctuate while in auto because it calculates the percentage open by the several other factors. The amount of fluctuation is actually minimal. I can actually go into the system and adjust the voltage range for open to close.

Granted an automobile will fluctuate more but, the percentage should still be in the 90 percentile range full throttle. If the computer calibrates the throttle to what ever the full throttle range is than the last .37v i got would just be a dead band. This I understand already. Now with the computer would it say hey there's more to this throttle and adjust tune or is it actually tuned to 4V. My point to this is if the throttle body is only achieving 80% actuation than up grading your throttle body would be nothing more than using a stock throttle body at full capacity.

 

Here is a datalog of my truck at WOT. The blue line that goes up and flat tops is the pedal in percent, so I got 100%. The teal line is the throttle angle actual. The ugly green line is RPM.

The throttle angle is clearly not open all the way, despite my foot being to the floor. These vehicles are controlled by torque output. So in this area I was probably making more torque than the PCM wanted, and it closes throttle to help resolve that conflict. I still made 390whp/480wtq on this run, and my torque in that area was nice and flat.

 

I have an Edge scan tool that shows my absolute throttle position to be roughly 81% when relative throttle position is at 100%.

 

This is precisely what I was looking for. This will probably become a future project for schnitzengiggles. Thank you very much

 

I think the PedalMax system would fix this.

 

Ive looked into these. Im wondering what precisely makes these work. It looks like an overly complicated box with a resistor and variable voltage adjusters.

 

But why? The throttle body opening or closing some has no affect on the power. This can be pretty much proven by looking at the amount of airflow the engine is taking in (airflow #/min). Airflow continues to go up, regardless of the throttle body. I can force the TB open with tuning, however the system will detract in other ways to meet the torque requirements, by means of spark, boost, or even fuel if it wants.

I know it sounds crazy that the throttle would close so far at WOT, but even stock Mustang 5.0, F150's, GT500's, Focus ST, you name it, if its drive by wire the throttle body is not opening at all times relative to the pedal.