No throttle response

[Don S]

So, I’ve driven this 07 for around 200k miles. It has 330k now and I’ve only found one issue with it that drives me crazy. It drives normal and has typical power, passing gear etc is all fine. But, if you get off in the snow, it will not accelerate. It’s like the accelerator pedal won’t do a thing. You can pump it and rpms will not fluctuate like it normally should. You can’t rev the motor up and down. Same thing if I’m backing a loaded trailer uphill and you need to give it more power to back up the hill. It totally falls on its face and won’t do a thing. It just idles. I should be able to melt the tires off this truck if I want to or plow right through any snow in my way. Instead it just sits there helpless and won’t let me accelerate in bad conditions. Drives fine on the road. I don’t get it. I should be able to blow the motor up if I so choose like a truck pull at the county fair but it’s dead on its face.

 

[mikez71]

I'm guessing traction control?

 

[mikez71]

something about ...the right of the people to keep throttle control, shall not be infringed.

That's why they let you unplug the wheel/steering/yaw sensors I suppose..

 

[j91z28d1]

something about ...the right of the people to keep throttle control, shall not be infringed.

That's why they let you unplug the wheel/steering/yaw sensors I suppose..

or just hold the button for a few sec?

 

[Marky Dissod]

So, I’ve driven this 07 for around 200k miles. It has 330k now and I’ve only found one issue with it that drives me crazy. It drives normal and has typical power, passing gear etc is all fine. But, if you get off in the snow, it will not accelerate. It’s like the accelerator pedal won’t do a thing. You can pump it and rpms will not fluctuate like it normally should. You can’t rev the motor up and down. Same thing if I’m backing a loaded trailer uphill and you need to give it more power to back up the hill. It totally falls on its face and won’t do a thing. It just idles. I should be able to melt the tires off this truck if I want to or plow right through any snow in my way. Instead it just sits there helpless and won’t let me accelerate in bad conditions. Drives fine on the road. I don’t get it. I should be able to blow the motor up if I so choose like a truck pull at the county fair but it’s dead on its face.

Guess we should assume that you disabled the Traction Control feature (GM used to call this Accelerative Slip Regulation ASR)?

The 'accelerator pedal' is an electrical signal, aka 'drive by wire' - it is NOT physical / mechanical, aka drive by cable.
The 'accelerator pedal' is treated by the pcm / ecm as a REQUEST, NOT a demand. GM's OE tune is specifically meant to discourage assertive throttle use.
The pcm / ecm decides when, how much, and how quickly to deliver your REQUEST.
In other words, your foot 'punches' it, but the throttle itself acts as if you lovingly placed your foot down and gradually rolled into it over a full second.
The end result, even without Traction Control, is it's more difficult to break the rear tires loose at will.

If you want it to be an unequivocal DEMAND that is acted upon without mitigation or interpretation, get your pcm / ecm tuned to stop second guessing your foot.
The other thing you should very seriously consider is 4.10 rear axle gear, but the tune should come first, whether it accounts for 4.10 or not.

 

[mikez71]

or just hold the button for a few sec?

Only problem with pushing the button, is it re-activates past a certain speed and it re-activates when you start the car.
You'll have to remember to press it EVERY time...

I'm not out there shredding tires, but Stabilitrak always kicks in when I make a tight turn and try to power out..
flat no response for about 2 seconds...

Possible a bad yaw sensor making it too sensitive?
It probably has to be that sensitive and pro-active to prevent a spinout..

I much rather have to push the button to turn stabilitrak on.. Or they should have a rocker switch for it.
(Yea yea, safety, people can't drive, insurance.. yada yada) = lame driveability.

BTW you can disable some traction control in the tune, but not stabilitrak. (I think it's in the EBCM)...
Unplugging the steering angle sensor is the easiest, most complete way..

 

[Marky Dissod]

Only problem with pushing the button, is it re-activates past a certain (road) speed and it re-activates when you start the car.
You'll have to remember to press it EVERY time.

I'm not out there shredding tires, but Stabilitrak always kicks in when I make a tight turn and try to power out.
flat no response for about 2 seconds.

Possible a bad yaw sensor making it too sensitive?
It probably has to be that sensitive and pro-active to prevent a spinout.

I much rather have to push the button to turn stabilitrak on. Or they should have a rocker switch for it.
(Yea yea, safety, people can't drive, insurance. yada yada) = lame driveability.

BTW you can disable some traction control in the tune, but not stabilitrak. (I think it's in the EBCM.)
Unplugging the steering angle sensor is the easiest, most complete way.

What can be done in the ecm, is 4 things (last I checked):
adjust the amount of spark retard used during a traction or stability event (old)
adjust the rate at which spark retard goes back to normal (old)
adjust the rate of driver power request (new) during a traction or stability event (new)
adjust how long each intervention is to last before a check is made to see if the traction or stability event is ongoing (new)

 

[j91z28d1]

I didn't realize it turned itself back on. that's annoying.

 

[Marky Dissod]

I didn't realize it turned itself back on. that's annoying.

How many of you realized that how often you turn off the stability and/or traction control is one of the many things monitored by
the little plug-in from your car insurance company?

 

[j91z28d1]

yeah I don't have the insurance plug in and I honestly never turn it off. it's a in town truck. the only time it's been in 4wd is to test it on a beach to see if it worked. honestly still not sure it worked since I didn't go spinning tires rutting up the sand road in 2wd first haha. this thing is basically a minivan as far as how it's driven. if a Toyota mini van wasn't like 3.times the price, seeing as they have about the same tow rating. one would have probably been the more practical choice. faster and more reliable too I'd bet.

I only know gm allows you to shut all the aids off by holding the button for 3-5 seconds because I have to do it on the c6 everytime I get in it. I've put a angle kit on it that changes the steering ratio but without a way to calibrate the steering angle sensor, it thinks you're over steering at every corner and freaks out. so you gotta turn everything fully off and drive it like an analog car. luckily the angle kit makes that safe to do where honestly without it, the horribly slow rack ratio made it uncomfortable to drive near the limit without some electronic back up.

that said I can't imagine I'll ever be hot lapping the yukon to need to turn it off or find out it turns back on. I did read somewhere in a manaul that going into 4 lo disables everything but abs if I remember right. I'm just trying to baby it along to. 300k without doing any major work to it like pulling heads. I got more than enough broker junk to work on daily haha

 

[j91z28d1]

Only problem with pushing the button, is it re-activates past a certain speed and it re-activates when you start the car.
You'll have to remember to press it EVERY time...

I'm not out there shredding tires, but Stabilitrak always kicks in when I make a tight turn and try to power out..
flat no response for about 2 seconds...

Possible a bad yaw sensor making it too sensitive?
It probably has to be that sensitive and pro-active to prevent a spinout..

I much rather have to push the button to turn stabilitrak on.. Or they should have a rocker switch for it.
(Yea yea, safety, people can't drive, insurance.. yada yada) = lame driveability.

BTW you can disable some traction control in the tune, but not stabilitrak. (I think it's in the EBCM)...
Unplugging the steering angle sensor is the easiest, most complete way..

I knew it defaulted to on every key cycle but didn't realize it could turn itself back on during a drive. I dislike unexpected things changing while driving.

there's a theory that that's why so many mustangs crash, even thou they have turned all the aids off, behind the scenes it's still active at the limit tyring to help but actually makes things worse. once passed a limit it's actually making things worse and fighting the driver while the driver is trying to keep tires spinning for that cool cars and coffee pull out. there's whole youtube vidoes diving into it. I just figure it's a driver failure but I do know even in a corvette, even in competition mode if you don't work with the ecm to gather the car up quickly, once it kicks in but actually want to expend a slide for a while it will start fighting you and make everything worse. I only did that a few times before disabling it all, adding a fdf angle kit so I could drive it like I wanted to.

 

[mikez71]

What can be done in the ecm, is 4 things (last I checked):
adjust the amount of spark retard used during a traction or stability event (old)
adjust the rate at which spark retard goes back to normal (old)
adjust the rate of driver power request (new) during a traction or stability event (new)
adjust how long each intervention is to last before a check is made to see if the traction or stability event is ongoing (new)

From what I could tell the settings affect traction control but not stability control.
None of the available settings can alter steering angle or inertia/yaw sensor related settings.

When disabled I could peel out from a stop, but turning still cut power I'm pretty sure..
I did not test thoroughly, but that seems to be the consensus online as well..

And while you can limit the amount of final timing pulled, I may still want some retard to smooth out the shifts..
(I actually don't know how much I want or don't want yet)

How many of you realized that how often you turn off the stability and/or traction control is one of the many things monitored by
the little plug-in from your car insurance company?

I will never allow it!

I did read somewhere in a manaul that going into 4 lo disables everything but abs if I remember right.

I think you're right about 4LO.. I was planning to install an ABS disable switch..
Reason being, I once slid down a VERY SHALLOW muddy slope and the brakes in my Toyota did not work.
I -think- the ABS freaked out and I just rolled down.. luckily they finally worked, because I was about to hit a pole.
I don't trust ABS in mud after that.

 

[j91z28d1]

there's also a ice mode coded in gm abs that pretty much can't be deleted. it might be what you hit. it's crashed a lot of cars doing track days. Just randomly hits, no one fully understand how the cal works. it's meant to say your wife is driving down the highway, hits a black ice bridge or patch, panic stabs the brakes. well the pedal is hard as a rock but doesn't apply the brakes. that's ice mode. only bad thing is, it also sometimes kicks in at the end of the long straight when doing a club day at the track and totals you corvette or camaro.

pulling the abs fuse is the only known way to 100% avoid it. but abs is useful on track, especially when your car has a stock braking bias setup to be used with abs.

 

[CMoore711]

This may or may not be related, but it may be applicable?

I’ve been experiencing an inconsistent issue with what is either related to steering or maybe a wheel speed sensor? Where every once in a while mid-turn or while turning and accelerating it will engage what looks like a traction control light on the dash and the throttle will hesitate or cut off. I thought maybe turning off traction control and stabilitrac might cause it not to happen, but it does not. Even with TC and stabilitrac turned off it will still illuminate a separate orange light that looks like TC, but it is not.

 

[Marky Dissod]

From what I could tell the settings affect traction control but not stability control.
None of the available settings can alter steering angle or inertia/yaw sensor related settings.

There are always 'unavailable' settings - and yes, I get that it's pretty much pointless to discuss them ...

When disabled I could peel out from a stop, but turning still cut power I'm pretty sure.
I did not test thoroughly, but that seems to be the consensus online as well.

Not sure, think that FoMoCo beat GM & ChrysCo to the punch with 'Progressive Traction Control', keeps track of front wheel speeds and steering angle.
If steering angle = 0° AND front wheel speeds are low AND very close to equal, Traction Control is disabled.
FoMoCo may have also come up with a more primitive version of Stability Control that simply compares wheel speeds?

I'm also 'pretty' sure that Stability Control, by its programmed nature, intervenes 'harder' in rough proportion to the steering wheel angle?

 

[mikez71]

In addition to showing whether abs, traction control, or stabilitrak is active or not,
a scanner can show steering wheel position, yaw rate, lateral acceleration, and over/under steer ratio?..
If you suspect one of your sensors is bad or mis-calibrated..

Is the separate light circle shaped? (abs or brakes)

 

[mikez71]

there's also a ice mode coded in gm abs that pretty much can't be deleted. it might be what you hit. it's crashed a lot of cars doing track days. Just randomly hits, no one fully understand how the cal works. it's meant to say your wife is driving down the highway, hits a black ice bridge or patch, panic stabs the brakes. well the pedal is hard as a rock but doesn't apply the brakes. that's ice mode. only bad thing is, it also sometimes kicks in at the end of the long straight when doing a club day at the track and totals you corvette or camaro.

How do people know it's an ice mode? Does it say on the display?
Hope it's not in our trucks!
But in my case it was a Toyota, and I was barely moving..

At the end of a long straight, could be pads outgassing?
I guess if it happens on initial braking, its not.

I experienced outgassing once when following a friend at 105mph, and police pulled us all over.
By the time I slowed down to ~25mph, the brakes suddenly got hard and braking felt waaaay reduced, almost none.
Almost hit the other random car that got between us that was being pulled over too.

Supposedly doesn't happen with riveted pads but happens with glued pads..

 

[Marky Dissod]

At the end of a long straight, could be pads outgassing? I guess if it happens on initial braking, its not.

I experienced outgassing once when following a friend at 105MpH, and police pulled us all over.
By the time I slowed down to ~25mph, the brakes suddenly got hard and braking felt waaaay reduced, almost none.
Almost hit the other random car that got between us that was being pulled over too.

Supposedly doesn't happen with riveted pads but happens with glued pads.

This is what slotting and dimpling are for, to give the gasses escape routes so the pads can really press up against the rotors.