Jim_PA

iTrader: (8)

The pedal seems ultra sensitive the way it is. Cutting a notch and bending it down closer to the floor might help. Probably what ill end up doing.

bowtieguy79

iTrader: (1)

I concur, its so touchy, makes it hard to not spin out on take off.

Jim_PA

iTrader: (8)

After looking at how my foot hits the pedal in the Yukon, it's pretty obvious that the pedal is designed to use only some of your foot motion to actually move the pedal arm. A good portion of your foot movement just gets used up by changing the angle of the pedal pad. If I were to just use the tip of my toe to push in on the bottom of the pedal, or lock-out the pedal pad movement, it would probably feel pretty sensitive.

The way my pedal is mounted in the truck, using the pedal with my foot transfers all the movement to the pedal arm, and none of the motion goes towards flexing the pedal pad.

I'll have to try to take that into consideration when trying to re-do my pedal. It will certainly take away some of that over-sensitive pedal sensation...

So, here's what I've learned (I think anyway...)

Adjustable pedals have significantly less overall mechanical travel than a fixed pedal setup.

The PCM must have a setting somewhere that tells it how much mechanical movement the pedal has.

I think 2 of my calibrations are for adjustable pedals, and the 2006 file I got from bowtieguy79 is for a fixed pedal.

Putting a fixed pedal on a PCM calibrated for adjustable pedals results in 100% butterfly opening at about 50-60% of the pedals range of motion. Holding the pedal past the point where the PCM thinks WOT is results in reduced power mode because the pedal is reporting motion that is out of the range of what the PCM is configured to use.

I imagine if you'd put an adjustable pedal on a PCM calibrated for fixed pedals, holding the pedal all the way down to it's full extent would result in about a 60% butterfly opening.

The APP sensors in the pedals are the same, the TAC modules are the same (as long as your TAC module is within the same range of years...), the mechanical pedal assemblies are different (adjustable vs. fixed pedals) and the PCM calibration needs to match the amount of motion your pedal has.

I have no confirmation of this, but if I could check the 3 vins I have, it would confirm that 2 of the builds came with adjustable pedals, the third did not.

I have about 4 months of research and lots of trial and error invested in making this discovery And now I feel even dumber than when I started.

Hopefully my discovery will help some other poor sap that is torturing themselves with this issue like I was.

So, if I'm right, all we need is a new setting in HP tuners that defines the amount of pedal travel available

BryanD

any updates or added info guys?

done a lot of the same stuff and having same problems. haven't really come to any good conclusions. getting tired of constantly mixing and matching pedals & tacs to get something to work. and when it does, i really don't know why.

i think if the wrecking yard would just give me the pedal & tac from the same vehicle the engine came from it would significantly simplify my life. but for some reason they keep giving me mix-matches!

i build turnkey engines for aftermarket. so this is a repeating problem for me. i'm about ready to shoot myself!

I do agree that if HPT would add a pedal recalibration sure would help.

Jim_PA

iTrader: (8)

No progress from me. I have not tried an APP pedal on mine, but it wouldn't really matter if it worked, as I'm not going to try to mount one of them in my truck.

I'm just going to put a new stop on my pedal, and do some cutting and welding to make the pedal a little more user friendly.

An answer to why it's happening would be nice though, wouldn't it?

bowtieguy79

iTrader: (1)

I was able to use a complete file rewrite on my 94, using the same file from my dads 95 ls swapped truck. It did the trick, no issues now.

Like I've said before, both my dads and my swaps, every piece, tac and pedal, came from matching trucks. It has to be a calibration issue...

Jim_PA

iTrader: (8)

Was that 95 swap using the 2006 OS you sent me a while back?

bowtieguy79

iTrader: (1)

Yup, same OS. But my engine and trans are the same as dads, 5.3/60e

BryanD

the last and only time we tried a rewrite it "bricked" the ECM.

the last motor I did had the 1/2 pedal - 100% throttle problem. ended up welding a stop on the pedal. odd thing is; with the welded stop gave the same shorter through as an adjustable pedal assembly I have also. there are significant differences in factory pedal "throws" complicating maters as well.

Jim_PA

iTrader: (8)

There has to be a setting somewhere that defines the range of motion that's expected from the APP sensor. EAP pedal equipped OS's have like a 0-60 defined range, non EAP equipped OS's have more like a 0-100.

I know it's not in the APP sensor, as the part number for EAP or non-EAP pedals is the same.