Originally Posted by justruck1

Plugged EGR back in made no difference, back to cummins and another couple grand to see if they can tell me why the boost dropped with a new turbo, good thing I have another truck with a Cat to keep paying to fix this Cummins.

Justruck,

So does the engine have low power now with the new turbo? Or is the boost gauge just reading lower? Reason I ask is with variable geometry turbos I have never really seen two act the same. You now have a turbo that is computer controlled essentially, so it might not act like the older one.
Also is this a new turbo or does it say Recon on it, which would mean it is a Cummins remanufactured turbo. I have seen some issues with Recon turbo's defective from stock.

Originally Posted by Smalltruck

Detroit uses a Delta P sensor that reads the before and after pressure of the flow from the EGR valve. If you unplug the EGR it will set a code and CEL. Mercedes and Cummins don't. Well the older ones anyway.

This isnt 100% accurate. Not sure about Mercedes but every Cummins ISX engine with an EGR valve does have a delta P sensor. The sensor reads the drop in pressure across an oriface in the egr connection tube and this is how it knows how much EGR gas it is putting in the engine. Without a sensor it would have no idea how much exhaust gas it was putting in the engine.

about early Mercedes. They istall EGR on top of engine with delta sensor and temperature sensor.

But if you swap ECM with non EGR you can remove all the EGR stuff and engine runs well.

By the way if someone has faulty non egr Mercedes control unit, I wanna get Flash (usually 29F400 ore 29F200) and EPROM (93C66 ore 93C86) for 12V ECM. I have 24V dumps only, so any hep will be appreciated.

With SCR Mercedes engine all things are not so clear. There is ADM unit in cabine and if there is SCR fault torque is limited by ADM (in EU mercedes names it FR ore FMR). I know only how to disable power and speed limitation.

The turbo I put on was a reman from Cummins, the engine does have less power so maybe it's like you say it is faulty, will have to see what cummins says about it, one thing about them, the dealer here is real good to deal with