I hope someone can help. im a tech working on a 2010 express g3500 6.6lt. its an ambulance with 332,000 miles it came in to the shop weeks ago at which time, another tech addressed a charging issue where he replaced the batterys and the altinator. vehicle now starts and runs. I just came back to work after being out with a shoulder injury for 6 months. I find out that the other tech had replaced the crank sensor and the pig tail. I get it for a crank no start. it took me some time but I finaly figured out that he had some wires crossed when he did the pigtail. so I fixed them and got the crank signal back. the vehicle now starts and runs. there was a egr code that I ran down and also repaired. so that's the history. my problem is when warmed up, at idle and running down the road, it feals like the fuel is cut off but im not sure. the rpms drop and it bucks then picks right back up. its a loss of power I cant explain. it almost feals like a dead miss but its not. now im not a desiel tech but I can figure out and research things well. what I have done so far is checked the fuel rail pressure actual vs desired and found that they were very close and stay close upon elevating the rpms. I aslo performed a injector balance test and all injectors are working. I don't know where to go from here. I would like the boss man to send it out to a desiel shop but we have so much in parts, time for diag and repairs so he wont. if anyone could help I would be very greatful.

 

could the fuel filter be almost clogged up , good enough to run but all the junk blocks the filter after running some ?

Thats what happened to my old gas powered van.....

 

I'll relay this to our fleet tech. He deals in almost nothing but diesel. Get back with what he says tomorrow afternoon.

 

I was thinking that but I looked back in our records and it was replaced 3 months ago.

 

Thanks you

 

Fleet tech says you probably got a bad crank sensor. Not unheard of to get a new part that's no good.

 

Ill swap it out with a new one and see how it goes. Thanks beau, ill let yall know if it fixes it.

 

Please do, my man said you went about the job the same way he would have.