Guess I spoke to soon about my good luck with my cab and chassis.

Going on a short run today, I shut my engine off while loading and when I tried to start back up the engine was just barely running and I had a dead accelerator. I shut the truck off to check for codes, there were none and restarted it. It ran fine, no problems at all. Went and completed the job, never shut the engine off, and went back to the yard. I decided to go home for lunch, the truck restarted fine and I forgot about the problem. After lunch I was called for another job and the truck would not start. Now the symptoms.

The engine, when it turned over acted like it had no compression, it would just spin. There was no check engine light, no codes, nothing. The lift pump was working, I could hear it. Got it to the dealer, they could find no codes, couldn't figure out what to do, then it just started. It is running fine, like nothing happened. To me, that is the worst thing that could have happened. Now I don't know what to expect, when will it happen again and where will I be when it happens. Today, I was in my driveway, 1/2 mile from the dealer, next time I could be 500 or 1000 miles away.

Tomorrow they are going to call star and try to find some answers about the seemingly lack of compression. Question to you techs, when the injectors are firing extra fuel for a regen, do the exhaust valves stay open or not stay closed as long as normal in order for the extra fuel to get into the exhaust stream? If so, could a computer glitch have caused them, the valves, to remain open and not let the truck start? Or, am I totally wrong on how the extra fuel gets into the exhaust stream.

 

If I read everything right. The injector fires an additional time while the exhaust valve is open. I don't think they have added any variable valve timing or solenoids to keep the valves open or anything like that. Sounds like a bad APPS sensor to me.

 

the cam is responsible for opening and closing the valves, it is not variable. the computer adjusts injection events to occur when the valve is already open for regen.

 

First two areas I would check is the APPS and the connections at the ECM.

MikeyB

 

Got my truck back this morning, I ran off and on most of the day, no problems. The tech at the dealership said there were no codes that had ever come up in the system, nothing. The people at star said they had never heard of this type of problem so I guess I'll run until it happens again and hope if it does, it sets a code then. Day before yesterday I had waited about 3 hrs at a pipe yard to unload idling all the time so I did have the fast idle enabled on my truck. I believe that might help. The tech did say that my truck had started 174 regens, and completed 96 of them. This was done in a little over 50,400 miles. I don't know how often it is supposed to be done, but that is what my truck has done. I guess I'll continue on like I have been doing and hope if the truck won't start, it's someplace close to a dealer. I know I won't be shutting it off out on a location in the middle of nowhere.

 

Just a little something I found. Ya might want to runs this by them and see if your truck falls within the guidelines, it's a ECM Flash.

I found a TSB, NUMBER: 18-038-06. It has to do with the Exhaust Pressure Sensor Rationality. My understanding is that if there is a problem with this, it will cause the engine to De-fuel, kinda like what your describing.

Just a thought.