Accelerator pedal "play"?

[Badunit]

It has always been difficult controlling the speed of my JT right off of idle. I think most, if not all, of the problem is that I have 1/4" of deadness at the beginning of the accelerator pedal. Unlike slack in a cable-operated throttle, there is no different feel to it to know when it is at the end of it so sometimes I undershoot and sometimes I overshoot. Using JSCAN I see some throttle sensors that change with the pedal movement from the beginning but the actual throttle doesn't do a thing (and no change in RPM) until about 1/4" into it. Is this normal on a JT? It certainly is not normal on any other drive-by-wire vehicle I've ever driven.

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[jac04]

You could try doing a throttle re-learn. It might help.

1) Get in vehicle & put on seat belt
2) Press Start button twice to put it into Run (do not start engine)
3) Wait for the engine light to appear.
4) Slowly press the accelerator pedal, taking about 5-10 seconds to go all the way to the floor, pause for a few seconds, then about 5-10 seconds to come all the way up.

 

[Badunit]

I have tried that so many times and also have done multiple throttle learn procedures with JScan. Nothing really changes. After many attempts at recalibration with no luck, I bought a new pedal. That did not help, unfortunately, but I think that eliminated it as the problem or at least reduced the probability.

With the procedure you posted, I am not clear on step 3. The engine light lights up, there is a ding, after a little bit the light blinks, then I think it gets steady again. I've started the procedure at each of those times with no luck at any of them.

One other thing (not related to the recalibration procedure) is that if I keep the pedal at a position just at where it transitions to doing something, the engine rpm and some of the throttle sensor readings jump around, surging up and down, often dipping below what they were at idle.

If anyone else has taken a look at the PIDs for the throttle on their JT, I'd love to know what readings they get. There are six different PIDs related to the throttle pedal and throttle actuator in JScan. None go to 0 when my foot is off the pedal. "Absolute Throttle Position D" goes to about 95% when floored (engine off) but it is about 8% when my foot is off the pedal. None of the others get even close to 95%. The one that is labeled "Throttle Position" ranges from 11% to 38%.

I tried ALFAOBD to get a second opinion but it wouldn't give any reading for the pedal . My Autel tool requires a $500+ subscription to use it on my Jeep so screw that and screw them. I feel like I'm working with hacker tools with my phone and an app and a bluetooth dongle and a bypass cable and a SGW extension cable but I don't want to take it to the dealer, even though it is under warranty.

 

[Janster]

Do you have an automatic?

My 24' Mojave isn't instant either.... Throttle delay or Lag (or whatever you want to call it).
I'm not necessarily convinced that it's a throttle issue - versus - a throttle + transmission shift points. There are times (warmed up) when the throttle acts as I'd expect it to.

My previous truck (16 GMC CAnyon) had similar throttle response lag.....It was known as the "Chuggle /Stutter". I'm convinced it was a transmission programming issue.....
Slow down to make a turn.... after the turn, step on the gas... chuggle chuggle chuggle. The truck didn't know how to downshift unless you buried your foot in it. However.... when using Tow/Haul mode (especially while towing), it shifted perfectly.

I actually had a Pedal Commander for a while. At some point (warranty), the dealership replaced the Torque Converter (took the pedal commander OUT) and some computer updates. That helped for about 3 months...then, it was back to 'same old'. GMC's have what they call "Adaptive Learning" - where it learns your driving habits/patterns and adjusts the shift points accordingly.

I just got used to needing to step on the gas harder ..... They never did have a fix for it. "It's a GMC thing....."

 

[Badunit]

Yes, automatic. I had been considering the transmission or torque converter as a possible issue but it happens in neutral and park sitting still so I have discounted them as related to the problem. Not that I don't have other issues. If I am braking hard, the downshift into first almost sends me through the windshield. Or if I am braking relatively hard and hit a bump (like a speedbump) it will downshift in that same manner and stay in that lower gear long after it could have upshifted. These kinds of things can make you lose traction in wet/snow conditions. These issues may become the subject of another thread.

 

[Hemy5587]

Pedal commander took all the delay out for me. Some on the forum don't like them and use a similar product from Banks. Sounds like either way a throttle controller would help you out with your issue.

 

[Badunit]

I have the Banks unit. I like the better throttle response but it does not fix this problem. It has no effect on the problem at all. At the moment it is disconnected.

 

[Hemy5587]

Interesting because with mine with the pedal commander sport+ and +4 it is so sensitive that it barks and jerks the truck repeatedly barely touching the pedal each time. It is the first vehicle I had to turn the Pedal Commander down on because it was too twitchy at sport+ and +4 (highest setting). Maybe you have a bad throttle body?

 

[Badunit]

Really my main questions are

1. Does anyone else have 1/4" of pedal travel before anything happens?
2. Does anyone else have this surging/hesitation just as the throttle starts to be affected by the pedal?
3. Does anyone else have this inconsistency where you don't know if you're going to start off at a crawl (or not move at all) or do a jack rabbit start when you lightly press the gas pedal from a stop?
4. Has anyone else has had this problem and got it fixed. If so, what was it? If it is normal, though, it sucks.

 

[Badunit]

I have considered it being the throttle body. I can buy one and swap it in but I was hoping to diagnose it as that first rather than buy and try. Sometimes buy and try is the only way to fix a problem as a DIY mechanic. I'm not yet convinced the throttle body is the problem. I also considered the MAP sensor and replaced it, with no effect on the problem.

 

[MrBones]

I checked on my drive today. From a dead stop I can sense some minor play but dang if I can tell 1/4" from 1/8" or 1/2". Just know it's consistently the same. The truck accelerates nicely and the front lifts some. Nothing that concerns me and a whole lot better than my 2016 JKUR. The only lag I can feel is on kick down to down shift but still nothing I'm concered about.

 

[Rusty PW]

I have the Banks Pedal Monster. Have it set at Sport 6. It's touchy. When the wifey drives the JT. I set it to Sport 1. Otherwise she will spin the tires pulling out.

 

[jav_eee]

Really my main questions are

1. Does anyone else have 1/4" of pedal travel before anything happens?
2. Does anyone else have this surging/hesitation just as the throttle starts to be affected by the pedal?
3. Does anyone else have this inconsistency where you don't know if you're going to start off at a crawl (or not move at all) or do a jack rabbit start when you lightly press the gas pedal from a stop?
4. Has anyone else has had this problem and got it fixed. If so, what was it? If it is normal, though, it sucks.

Yes I have the issue. Impossible to control at very light throttle like through parking lots or going down a long slow driveway. It’s jerky and I hate it. I have tried the throttle relearn with no joy.

 

[Volt0]

I have the same issue; usually when at a divided highway, stop, see an opening, and try to get across. Sometimes it'll go ahead and get going, other times the delay/lag is so bad that I have a split second or two where I'm wondering if the vehicle is just going to peter-out while I'm broadside to oncoming highway traffic. I don't need more aggressive shift points ( like OR+ ), I just want it to "go" when I tell it to, in a consistent manner. That initial stutter/gap/deadness/lag seems to be worse when I'm in a bit of a hurry, or when the gaps of oncoming highway traffic are a little tighter than I would like; it doesn't seem to be an issue at 4-ways/3-ways where I wait for other vehicles before going.

 

[legacy_etu]

Really my main questions are

1. Does anyone else have 1/4" of pedal travel before anything happens?
2. Does anyone else have this surging/hesitation just as the throttle starts to be affected by the pedal?
3. Does anyone else have this inconsistency where you don't know if you're going to start off at a crawl (or not move at all) or do a jack rabbit start when you lightly press the gas pedal from a stop?
4. Has anyone else has had this problem and got it fixed. If so, what was it? If it is normal, though, it sucks.

Sorry, can't relate at all. My pedal is smooth as can be and I sense no delay from the moment I touch the pedal. No surging or control issues either at light pedal input. Stock Mojave drivetrain, no throttle controller mounted.

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