Glad no one was hurt! But that is the great thing about the 6spd. You can down shift to keep the rpms up and the mph down. the govoner will only let the rpms go so high and you could have kept up with traffic without trying to run over those in fron of you. Try it with everything working.
Fred

 

I agree with the floormat theory....because A) it happens alot and B) he says that the pedal was "stuck down"...the pedals on these trucks are just possions sensors with a return spring...there is nothing that would physically keep the pedal on the floor (other than the floormat), if it where a computer/cruise problem the skinny peddle would not stick on the floor.

 

The APPS utilizes a 5 volt input, a signal return, ground, and TWO idle validation switches. For the pedal to return to idle position, and the ECM not see either of the validation inputs.....and not set any kind of idle validation dtc????? Not sure what to tell you.

 

FLOOR MAT! Only thing left! LOL Hope you get it figured out seriously though. Maybe there was a code and he didn't check. Can't wait to hear what the dealer has to say though.

 

Floor mat...Happened to me ONCE and only once, with my 05 ctd. Also happened to my Dad once. Ofter that we both decided to trim the new mats.
We both bought our trucks within a few months of each other and both bought those fancy after market floor mats. The new plastic or rubber was just stiff enough to hold the pedal to the floor. Both of us were stomping the gas to get on it when this happened.

I really really hope for the sake of you and your families poor nerves that your able to point to the fault of the floor mat. Other wise I doubt I'd be jumping right back in myself.

Good luck and let us know what you determine.

 

I find it hard to believe that it is a floor mat that did this. I think it might be something electrical, since he saw over 4K RPM. Isn't the limit supposed to be 3500 RPM in neutral?

 

Yeah, I would have to agree with that theory as well...The RPM numbers aren't making alot of sense to me either unless he did something to try and slow it down by shifting down the gears but it remained pegged to the floor.

Who knows, when that happend to me, I too dropped it into neutral in order to stop it. He on the other hand was pushing the brake pedal throught the floor...

 

Something the factory guys on here might mention is there is no "throttle" to stick on these engines. Like most diesels these engines don't have a throttle plate to stick. The fly-by-wire controls speed by controlling the amount of fuel injected. This is diesel operation simplified, and I'm sure many of the old hands are literally groaning, but unfortunately most of us aren't pros and start somewhere in the middle as to our understanding of how these things work. One of the advantages these engines have is not having a throttle plate in the way causing pumping losses. The point is unless you have a TOTAL snafu in the computer which is just as likely to make the engine not run as it is to runaway, it was probably a mechanical problem with the apps linkage. That is a floor mat or a loose underdash wire snagging the "throttle" linkage, or the the pedal.

 

Not to disillusion the factory techs that read these things.

Once, and only once, I ran into a 99 dodge, which had no floormats at all, hence nothing under there to hang a pedal on, and when the APPS failed, it went wide open throttle. All by its innocent little self. It screamed like the above mentioned truck, until it could be pulled over and stopped.

After getting it stopped, still at WOT, with the pedal in the released position, the truck was shut off. When restarted, the throttle worked normally for approximately 5 minutes of the drive back to town, and went WOT again. At that point, it was shut off again, and restarted. This time, it would only idle, and nothing else, APPS was done.

We idled the truck back to town in 5th gear, ( roadside really doesn't work here ) and to the dealer, APPS was replaced immediately, no further problems with the unit, until a VP failure. Now, this APPS went out at less than 2500 KM. The VP on that truck failed at less than 19,000 KM.

It can happen.

Looking forward to seeing what happened in this case

 

I hate to mention it, but here is a throttle plate on the 6.7's

Used to limit airflow and build up heat for regeneration.

You are right that there is nothing physically connecting the engine to accelerator pedal. There hasn't been since 2003. Even then, it was just a cable to the pps (pedal position sensor) on the engine (alah 1996-2002).

 

BB2stroke,
Even if there is throttle plate it wouldn't cause the truck to run away if stuck wide open. The control is still the pump. Please correct me if I'm wrong. A control plate like that would be more of a "choke" plate.

 

Right, I never said it was the cause. I was just pointing out that there is a throttle plate and yes, its use to "choke" the engine to build heat in the exhaust.

Usually, the only thing that causes a runaway is a fuel system issue.

 

Sorry guys but what is the APPS sensor and what does it do?

 

APPS = Accellerator Pedal Position Sensor

 

Hey Axlerod50, Did you ever find out what was wrong???