Since I got my truck almost 2 years ago I have noticed that if I hit the gas and then let off it seems as though the engine doesn't react right away, and it seems to have gotten a little worse over time. It seem like the engine keeps fueling for a fraction of a second or so more after getting off the throttle. I have found it to be the most extreem when you are stopped, floor or nearly floor it and then let off almost right away (aka going up a curb or when your backing up a short steep hill.)

I have had to stand on the brakes for all they are worth on several occasion because the truck was still fueling, when it should have been idleing down.

I have experimented with it and found that if I floor it until it just starts to build boost and then get off the trottle completely, it will continue to rev several hundered RPM more before slowing down. While doing this is still pulling so hard that I managed to klunk the brake peddle on the floor and still had the truck gaining speed!

Any input will be greatly accepted on what is causing this and how to prevent this.

 

they all do it I hate it with the smarty I can lay rubber for 2-3 seconds on its own Ive had to knock it out of gear its scary at times

 

Well I'm glad to see that there is at least one other person out there that knows the feeling.

I'm still really wondering why the engine does this... its borderline a safety issue in my mind.

 

What is a 2003.5?
Joe

 

A 2003.5 from what I've been told it when Dodge made the complete change over (excluding California i think) to the 305hp/555tq with the 48re. Prior to that it was still the 47re with 250hp.

Other than that I can't remember what the few other minor "adjustments" they made for 03.5.

 

HAHAHA Nothing like flooring the throttle and wondering why the truck wants to go for 2-3 seconds. HAHA You start the turbo to spin and the computer feeds fuel in relation to turbo spin , takes a moment for things to come back down to idle. HAHAHA

 

Chaulk up another one to the NVH guys.

The fueling slew rates are adjusted like that to keep the turbo compressor from surging (turbo bark, better known as turbo chuff).

A small portion of the slew rate is also attributed to trying to extend the life of the u-joints.

 

bigblock2stroke

I was always wondering if it had anything to do with preventing turbo bark. I know my 01 would bark pretty easy, even bone stock, but this one doesn't bark at all.

It makes tons of sense, but I would rather take the risk of barking the turbo, than listening to the barking of the insurace company after I flatten something or someone with my "run away" truck.

So thinking about it in this new light, has anyone come up with a tuner, box, etc. that changes the fueling in a why that stops this behavior?

Also, Whats are "NVH guys?"

Thanks a ton for the info,

Mike

 

I've had it do this without any boost.

When I installed my Bully Dog Triple Dog, I was looking out my side view mirror to see all the smoke that I was putting out by just stabbing the throttle a couple of times while it was out of gear . On the third time it kept on running for about three more seconds.

I had originally thought maybe it was just "loaded up" like a gasser.


..............Jim

 

Well thats as good description as any although I think its more of safety feature for the rail than the turbo.

When you dump from WOT the APPS has to tell the ECU its closed then the ECU has to tell the FCA to shut down fuel to the rail and then the rail pressures have to drain off before the delivery slows down.

Not bleeding the rail pressure off slowly would lead to some nasty high rail pressure spikes.

 

It all happens in microseconds, but you are probably right.

All I know is that the slew rates were good (they were tuned to allow the engine to decelerate quickly without spiking the fuel rail pressure), before the Noise, Vibration, and Harshness engineers complained of too much chuff. The performance guys (like myself and most others on this thread) would certainly rather have a little more potential for chuff than having to wait for the engine to decelerate after letting off the go pedal. The NVH guys have more and more pull with each model year. Almost as much as the Marketing, Safety, and Accounting people.

 

LOL! Oh, I don't doubt there are multiple things in effect that is causing this and that is probably right on target. What is annoying is this almost becomes a safety concern if one is not familiar with the reaction. A little too much throttle in a parking lot and things can get interesting if somebody backs out of a space.

I guess the they think we all drive with one footon the accelerator and one on the brake.

 

But who is driving the Noise Vibration Harshness guys to these lengths?

Supposedly we, the consumers?

 

my friends sister rolled his truck cuz she didnt know anything about the power surge after getting off the fuel... she stomped it, and the truck kept going and she lost control... chauk another one up to now knowing your vehicle.

 

... or perhaps to women drivers?