Hello to the Forum, This is my first post. I have a 2006 Ram 2500 with the 5.9 Cummings. The truck has 92000 miles and is not modified in any way from stock. All servicing such as fuel filter changes, other filters and oil changes have been carried out as directed my the owners manual since new. Last week the truck began to experience unwanted acceleration from around 60MPH to in excess of 90-100 MPH. The only way to control this unwanted acceleration was to put the tranny in neutral and shut the motors off and use the brakes to slow the truck. Upon restarting, the truck would again do the same. We began trying to get the truck back home this way but it finally quit and would not start at all and had to be towed. Once at the shop the truck would not start but then on the 2nd day at the shop it started and ran OK around town. The shop diagnostic computer "throws" to codes to indicate something is wrong. Any ideas as to what is occurring with this "run-away acceleration???? Thanks, Jerry Poole

 

Jerry, can't help with the problem because I'm new to diesels myself, asked a mod to move to the diesel forum where you may get more answers

 

I moved it to Diesel for you but it may be much more of a universal thing....
The 2006 is a Drive-by-wire gas pedal in gasoline models. I'd expect diesel to be the same.
I would have the sensor for your gas pedal checked for inconsistencies and or just replaced for safety reasons.
The gas pedal sensor transmits pedal position to the Throttle body.

 

What are the codes?

My money is on one or more fuel injectors being cracked or otherwise faulty.


If it was a APPS issue, I would expect no throttle response due to a fail safe mode.

Typically there are two sensors in the pedal assemblies, and they're not parallel outputs so the computer can take Value 1 and do a computation to figure out if it matches Value 2. If they don't match due to a fault in one of the sensors, it figures the pedal is bunk and goes into limp mode.

Fuel injectors are a common enough failure in common rail trucks, and somehow you're getting extra fuel injected until you shut off the injection pump. There are a limited number of reasons for these trucks to run away - they're compression ignition so you could be driving through a dense cloud of gas (propane, etc), you could be sucking oil somehow, or your injectors are dumping way too much fuel.

 

While I am new to this engine, I guess my first thing I would check is to see if perhaps I had lost the seal on the turbine compressor. Look at oil level in crankcase, also pull induction hoses and check for oil. I remember many years ago driving a Massey Ferguson combine and loosing a seal, and the engine ran away until it melted down.