4.6 V8 over rev/6 speed issues

[Galen Burden]

I have some questions, do tuners have the ability to change how the drive by wire comes off throttle? When you rev it up, the motor slows down very slowly as if the throttle blade is closing very slowly. My truck did this before the Bama Chips tune, still does it.



Does the drive by wire move the throttle blade exactly as your foot moves?



If the drive by wire is causing this "slow engine slow down" and the program could be changed to move the throttle blade exactly as the pedal moves, would this screw something else up?



IMHO, this "slowly return to idle" one of the things that is driving the 6 speed trans nuts. When I come to a stop, its like I still have my foot on the gas and the brake at the same time, as the tranny downshifts, the motor is at a relatively high rpm/throttle setting and the trans goes BANG when the truck is finally moving slow enough for the trans to shift down to low gear.





Opinions?

 

[Gavin Allan]

The slow decell is used to reduce emissions. Can't remember which ones, but cars since mid-70s even with carbretors have used some sort of device / dashpot to slow decelleration to reduce emmissions.



I agree with the problems you've identified, however. Wish I could get around them too with my Trac.

 

[Tom Schindler]

Does the drive by wire move the throttle blade exactly as your foot moves?

No it doesn't. The ECU has been given the power to control what you do with the throttle. You want to floor it, it says it doesn't want yuy too, it won't!



If you think it will rev like a race car, it won't. If you think it should drop to idle instantly, that isn't going to happen either.



All engines will drop to above idle and then settle at idle.





Tom

 

[Galen Burden]

Never expected it to rev like a race car, just slow down when I take my foot off the pedal.



Anyway, I think this issue is a major contributor to the 6 speed trans problem so many have.

 

[Eric Gutknecht]

This behaviour also is affected by the weight of the flywheel and the inertia/weight it has when spinning up and down...



Cheers;

Eric