isx black smoke, fuel knock, engine year 2009 running rough

[Rawze]

if it is blowing black smoke and it still has DPF intact then that is a high possibility that it is cracked and blocking up the exhaust partially.

Start by Pulling the DOC and DPF off and inspect them, take pics of their faces (post em here for some opinions), have them baked, flow-tested and cleaned out.

When is the last time you replaced IMAP and opther sensors, and did an EGR tune-up? -- Anyone check to see if the EGR valve is closing and opening properly?

Anyone check to ensure the Doser injector is not leaky and bleeding fuel into the exhaust?


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as far as air bubbles in the return line,... that can be totally mis-leading. The CM871 engine fuel system is known for cavitation in the return circuit and quite often shown bubbles when the return line is placed into a bucket, even when there is absolutely nothing wrong with it. - Take it with a grain of salt. - Do what I suggested... pressurize the fuel tanks to 10-15 psi and see if the problem clears up and/or if there are fuel lines leaking going to the engine.

Also do cut-out tests and check actuators, injectors, etc.




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high amunts of black smoke + fuel knock (when injectors, overhead adjustment, etc. are good) are usually...

* Stuck open EGR valve.

* Engine being choked severely by the turbocharger or other exhaust restriction.

* Too low of injection timing due to slipped cam(s), bad programming, bad timing actuator(s), or bad wiring to one of the actuators.

* A severe blockage in the intake past the turbo.

* Severely Mis-reading exhaust gas pressure (or blocked cross-pipe for it) or IMAP sensor(s).