CM871 poor power and fuel econ

[Rawze]

(04-09-2022 )Grounded Pilot Wrote:  I did the leak down test and replaced the injectors. #4 was obviously bad. Blew multiple bubbles every revolution and less resistance against the handle when turning it through. #1 only blew a small bubble, but did it every revolution. But I have not retested it since putting it back together so I will do that again. The only thing that changed, apart from taking the overhead apart and putting it back together, was the injectors. And after I fired it back up, it would shut down correctly and has since. So maybe a slightly bad actuator and bad injector combo caused the run on???

The reasons we ran the cutout test are low power, rough running, and a white haze at idle and puffs white smoke if you tap the throttle while idling. No oil usage and no water loss. The mechanic did the cutout test while I was watching and talking with him. Rear bank ran good and exhaust cleaned up. Front bank ran rough and the haze was present. Both fueling actuators had the tops popped off while driving and we replaced the timing actuators for excessive side play. All had some debris in them but not much. All looked to be original equipment with 925k miles.

Then the next thing to do to find the hazing and smoking at cold idle is to slide the exhaust manifold away from the head a bit and fire it up. .. see what cylinder(s) it is.

Also to inspect it for wet exhaust valves... make sure it is not leaky valve guide seals.