07 int cummins isx

Get the truck away from that dealer.

That turbo cough is an egr system issue 99 times out of 100. Did you try unplugging the egr valve?

When was the last time the egr system was cleaned?

 

Your 07 has a cm870 version of the isx. No dpf, egr valve on the right front of the engine.

I spent several months debugging an 07 9400 that wasnt quite as bad as you describe but drove me crazy at times. Egr valve was stuck partially open, pretty much every egr passage clogged with soot, and every egr sensor clogged up.

Knowing what I know now I would start by cleaning every egr passage and replacing all the sensors. Take the egr valve off and verify its functioning. If it is then clean it or rebuild. If not obviously replace.

I never had black smoke but I can see where a fully open egr could cause it.

 

how about dark fuel? can you explain why fuel is dark? ))) this is not egr valve issue .

 

Dark/dark blue fuel means soot in the fuel. 90% bad injector o-ring, 10 % cracked head. It is easily diagnosable. Run high rpm and with flash light look for bubbles in fuel tanks.

 

Pete the top picture is the egr valve. It is right behind the water pump on the passenger side.and I agree with mhyn