Drive by Wire super touchy 5.3 Vortec

[werrea]

So, does anyone have experience with their drive by wire throttle being really touchy. Man...It's starting to get to me. 1st and 2nd gear can be bad and if I am hitting bumps, my foot on the accelerator causes the motor to fluctuate in rpm a lot.

Any suggested solutions?

 

[MANUCHAO]

DBW usually have a lag (delay) response.
I notice this lag response at times only.
That is why most peeps swap to a cable activated gas throttle/pedal.

The symptoms you are describing make it sound like a sensor malfunction.

Some engines have their own DBW PCM between the gas pedal and the actual engine PCM..
I dont know if that is what you have, but you might want to swap for another.

I also want to say that it might be a program issue with the engine PCM, but you did not state if this problem has been there from the get go and just started...

Let us know what you end up with.

 

[werrea]

DBW usually have a lag (delay) response.
I notice this lag response at times only.
That is why most peeps swap to a cable activated gas throttle/pedal.

The symptoms you are describing make it sound like a sensor malfunction.

Some engines have their own DBW PCM between the gas pedal and the actual engine PCM..
I dont know if that is what you have, but you might want to swap for another.

I also want to say that it might be a program issue with the engine PCM, but you did not state if this problem has been there from the get go and just started...

Let us know what you end up with.

I have done some research. The motor is from a 2005 which from reading the Vortec forums did not have lag. But in 2006 and forward they have lag built in. People swapping in the motor have complained about the lag. But for me, it's almost like a 1:1 ratio. No lag. Coupled to a 5 speed, hitting bumps causes the throttle pedal to bounce on my foot. And I can get the truck to jump quite a bit. Very annoying when trying to be smooth.

Problem has been there since I purchased the truck. My guess is that it was always like that since BTB did the conversion.

Also kind of embarrassing when you try to pull out fast in first and it hops and the only solution is to let off the throttle.

 

[MANUCHAO]

Yeah, cant complain about the lag... it does not happen that often and I have a heavy pig.

Re: your throttle issues... I want to say you might also want to change the throttle body on the engine but you have not got any codes, right ?

Sorry I can be of more help...

 

[FJ62INTX]

Sounds like a torque management issue/tune adjustment possibly on the DBW setup for the 2005.

a good tuner should be able to soften the response a little for You and keep it from being so touchy I would think.... You might check with BTB and find out who programmed the ECU for them to remove the VATS, etc. and see if they might can adjust it for free or a small fee.


I had a Dakota 4.7V8 with the 5 speed brand new in 2002 and it also did this for me when I drove it...

It was happening because it was a manual tranny and had a lot of torque at even low RPM when You bumped the throttle



P.S.- If You don't fix the Jumping/bucking, You can always rename your cruiser to Jackass instead of Yeti.... haha

 

[workingdog]

I have the same set up in my FJ60 and the throttle is only touchy when dead cold. Either the throttle is sending the right data to the PCM or there is another problem. Don't re-program the PCM yet. Do you have a way to display the throttle position? A OBD II gauge or scanner?

 

[werrea]

I have the same set up in my FJ60 and the throttle is only touchy when dead cold. Either the throttle is sending the right data to the PCM or there is another problem. Don't re-program the PCM yet. Do you have a way to display the throttle position? A OBD II gauge or scanner?

No but I can take it to the shop that has been working on it. Only problem is they don't have a programmer to change any settings. The Chevy dealership wouldn't touch it.

 

[FJ62INTX]

I have the same set up in my FJ60 and the throttle is only touchy when dead cold. Either the throttle is sending the right data to the PCM or there is another problem. Don't re-program the PCM yet. Do you have a way to display the throttle position? A OBD II gauge or scanner?

Also, Yours has a 4L60E with a converter which greatly masks an overly sensitive throttle input unlike a manual tranny and a clutch....

I like where You are going though to check the throttle position!

 

[rcmccars]

dose it have a factory or aftermarket pedal? if its factory was it shortened? a shortened pedal will be more touchy because it wont travel as for as a longer one. check for welds on the arm if it was shortened you can install a heaver spring to reduce the amount of leverage you have on the pedal. if its aftermarket like a lokar or something it might just need to be calibrated. there are two sensors in the TB and and some more in the pedal if any of them are out of range of each other the pcm will go into reduced power mode so I dont think that's your prob. I just went through that on my cruiser. (corroded wire) pita. post up pics of the pedal if you don't know what stock one looks like someone will let you know.

 

[werrea]

dose it have a factory or aftermarket pedal? if its factory was it shortened? a shortened pedal will be more touchy because it wont travel as for as a longer one. check for welds on the arm if it was shortened you can install a heaver spring to reduce the amount of leverage you have on the pedal. if its aftermarket like a lokar or something it might just need to be calibrated. there are two sensors in the TB and and some more in the pedal if any of them are out of range of each other the pcm will go into reduced power mode so I dont think that's your prob. I just went through that on my cruiser. (corroded wire) pita. post up pics of the pedal if you don't know what stock one looks like someone will let you know.

Will take a shot of that tomorrow. Thanks for the help guys. If I get this fixed my wife and two year old will be very grateful.

 

[werrea]

Will take a shot of that tomorrow. Thanks for the help guys. If I get this fixed my wife and two year old will be very grateful.

Here a couple of shots of what I have. Doesn't look like it's cut.

 

[FJ62INTX]

There is always the idea of changing the return spring tension to something different.... maybe a stiffer spring might help....
or adding an additional spring to the one that is there already?

especially if it is occurring during a bumpy ride.. maybe a little different tension would help

it would be a heckuva lot easier than a bunch of tuning....

 

[werrea]

There is always the idea of changing the return spring tension to something different.... maybe a stiffer spring might help....
or adding an additional spring to the one that is there already?

especially if it is occurring during a bumpy ride.. maybe a little different tension would help

it would be a heckuva lot easier than a bunch of tuning....

Agreed. Will see what I can find tomorrow at the hardware store. Thanks for the feedback.

 

[MScatena]

I've worked on a few LS Swaps, you need to have the ECU looked at by a programmer. Do you know who did the original ECU work? They paid for the VIN key once but if you don't know can't find out then you'll have to pay for a new VIN key likely.
1. calibrate the throttle for proper WOT (wide open throttle)
2. adjust the sensitivity (usually 0-10 step stetting, most are about 4 steps) for "tip in & out" response (when you tip in to the throttle how fast does the ECU respond and how fast does it retard)
3. make sure all the other parameters still function properly

 

[tclark]

One good thing about my 2F--doesn't matter if I floored it, the rig just continues to glide along smoothly...

 

[werrea]

I've worked on a few LS Swaps, you need to have the ECU looked at by a programmer. Do you know who did the original ECU work? They paid for the VIN key once but if you don't know can't find out then you'll have to pay for a new VIN key likely.
1. calibrate the throttle for proper WOT (wide open throttle)
2. adjust the sensitivity (usually 0-10 step stetting, most are about 4 steps) for "tip in & out" response (when you tip in to the throttle how fast does the ECU respond and how fast does it retard)
3. make sure all the other parameters still function properly

Thanks. No luck on ecu work but I bet BTB would know.

 

[werrea]

So after trying 3 springs I finally found the right one that did the job. Sure it's a stiff pedal, but I like it and it doesn't bounce as much since my foot isn't bouncing on the pedal.

Thanks for the Spring recommendation.

 

[rcmccars]

glad to hear you got it to work for you.

 

[Spook50]

Isn't there a way to eliminate the drive by wire on newer Vortecs?

 

[lehiguy]

Are the ECU and the throttle body from the same donor rig? I heard of others having similar issues with parts form different vehicles being less than perfectly compatible.