6.7 Intermittent Engine Problem

[JohnBower]

Friend has a 2007 that has an intermittent problem. Sometimes when he starts it up, it runs ok and other times it almost acts like it is in a limp mode. It won't do much more than idle. He gets no MIL and dealer hasn't been much help so I thought I would ask here.

 

[wjpatton]

I've had this event 3 times. (2007. 5 3500 quad cab auto) Shut off and restart 3 times in quick sequence restores normal ops, but the problem seems to be with the electronic throttle and carbon buildup in the turbo, according to the dealer. Original turbo cleaned twice, then replaced. 35,000 total miles, mostly highway. 10,000 of those towing 13,000 pounds...

 

[Bob4x4]

If it goes away shortly after start up it is normal. There is software to protect the turbo on cold start up when out of gear.

 

[wjpatton]

All the times I had this event happen, the truck was in gear and the engine warm. Very little throttle response and almost NO power until the third recycle of the ignition key.

 

[Bob4x4]

Some of the early 07's had issues with the "throttle Body" have the dealer contact Star. They will walk the delar through the test procedure. Very simple procedure.

 

[sag2]

Unfortunately the ECM does not keep track of the throttle position so diagnosing is difficult. It tracks everything else, not sure why they left this out. If it sticks completely closed it can stall the engine.

 

[wjpatton]

So what you guys are saying is that due to the "fly by wire" nature of the interface between the accelerator pedal and the throttle body, the controller for the throttle body could be commanding more throttle opening, but the throttle body could be sticking. Multiple on-off cycles simply free up the throttle body until the next episode, whenever it may be. Is that about right? Will the J35 help with this as well as de-sooting the turbo??