I just did a in frame overhaul on a 5.9 Cummins in a 97 single axle dump truck. The truck is weak on bottom end when it hits 2400 RPM it comes alive. But when you shift the RPM drop back to below 2400 and runs like a dog again. I Just pinned the pump and the front gear so everything is in time. I was wondering about the android valve on the pump which is fed by the turbo boost. I haven't checked the boost yet to see what its doing at what RPM. Is there any Information on what the boost should be at what RPM? Anyone had this problem before or am I barking up the wrong tree?
Thanks Grandpa Rat 409

 

could definitely dial some preboost fueling in to get so ***** in the bottom end

 

Boost should peg about 17psi max under load when stock.

Cruising down the highway at 1800rpm in OD unloaded should be about 5 psi.

 

check to see if the waste gate is stuck open.