This site is a great tool for both experienced and novice diesel owners to gather and share info on keeping these trucks running.But I keep reading over and over that it is normal for the engine to stay revved until the pressure bleeds off the CP3.This simply is not true.Think about modern vehicle safety..lawyers,NHTSA ect.An engine design that would allow uncontrolled,continued acceleration after the throttle is lifted ,simply put,would never make it from the drawing board.I know the next few posts will say they know it is normal cuz"mine did it the day I picked it up new" I work around an entire fleet of these trucks and if you have one doing it,it has an injection sys problem.Whether it be inj,tubes,seals whatever.Thats why we keep reading about burnt pistons,cracked rings,poor mpg ect.Why are so many owners in denial about this?Also,this bad info could cause a novice to purchase a truck that has a problem,thinking it is normal.We need a definitive thread on this subject as not to mis inform folks.After re tqing my tubes,still had it. 6 new SS body injectors and NEW tubes..gone..old tubes..no scarring/bad places ect where they seat.Please dont flame me,just an important fact that needs to be discussed.

 

The truck was about 1 year old and I floored the throttle in 3rd gear. It was at 1500 RPM. It excellerated very quickly, I got off it at 2500 and it continued to 3400 before it started to slow. The excelleration from 2500 to 3400 took less than one second. I was concerned that I had damaged the engine and I have never done that again but it does take a short moment to go from full throttle when towing to deceleration.

 

My truck was at Enterprise in Thornville.The owner(top flight person and shop) explained the injector issue.He builds some of the best CR's out there and understands them to the T.When throttle pedal is released,the ecm immediately sends a signal to close,and worn/damaged cant properly meter the fuel at higher rail pressures.A properly functioning inj will imm close to the proper position and the fuel sys starts returning excess fuel.

 

Your mixing too many subjects and trying to use a blanket statement across all to describe what should not happen. You have to look at each one individually to make sense.


Engine continues to rev after releasing throttle - without a load that is normal. Simpy physics. Under a load, it is not mormal. Once the throttle is released then engine will maintain rpms then ramp down. How fast it ramps down is a function of the load on the engine. Again, sinple physics and if it doesn't react that way ther may be a problem.


Engine holding rpms after releasing throttle - Normal until the fuel that is being injected is stopped or ramped down. There is no throttle plate to chop air flow like a gas engine so fuel has to be reduced. Even with a full mechanical linkage there is a lag between lifting and and engine reaction. Again, how fast is load dependent.



Engine slowly returning to idle - it took time to rev up, its gonna take time to slow down. It is physically impossible to slow heavy rotating masses any slower than can safely be done. This is in part what the ramp down injection does, in addition to keeping the turbo from blowing up. Its the nature of the engine design and operation.


A diesel engine is NOT a gas engine. Let me reiterate, a diesel engine is NOT a gas engine. They react differently and are controlled differently. As far as liability, the operator is responsible for safe operation. If the truck doesn't slow fast enough to avoid collisions, SLOW DOWN.

The balance between engine design and what is trying to be shoved down our throats as "safety" is a moot point. Its been tested, its been approved, it works. Too broad an interpreation is just going to confuse the issue.