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All- I have a 2013 Ford F750 with the Cummins ISB 6.7 with two issues recently that I’m guessing are connected. Two codes are recurring: crankcase pressure high and differential pressure high. The truck will do a forced regen from Insite, but gets the high pressure code again within a few hours of driving. Crankcase pressure code goes away during regen, but comes back within minutes of hitting the road.

So far: EGR has been cleaned, crankcase filter replaced, differential pressure sensor replaced, NOX module replaced.

This is a roll-off dumpster truck, meaning short routes and hours of idling/low power.

Where do I need to look next? And, yes, I’m ready to demandate, but I don’t want to mask any bigger problems that may be occurring in the engine.

Thanks!

After typing this out I’m thinking that my first step should be checking for blow-by. Couldn’t that also cause the DPF to be constantly clogging?

Are you loosing coolant?
Could be a leaking injector
Or dpf needs to be baked and flow tested
d

Thanks hhow.

Not leaking coolant

I’ll search for injector leak test on here

I would absolutely check the blowby first.

Definitely getting what looks like fairly significant blowby based on air/oil/vapor coming out of the filter housing and breather tubes. Haven't measured using a manometer, but I think I have my answer based on the crankcase pressure reading, right?

I know blowby can cause the DPF to clog quicker, but can a clogged DPF that won't fully unclog cause excess crankcase pressure?

It can...if combustion cant get out the dpf it will vent anywhere it can find a path, even through the rings as well as exhaust pipe joints, egr valve, turbo, etc

Check with Ford as some of these were victims or bad air cleaner/piping resulting in dusting/early engine failures.

(12-22-2018 )Moose Wrote: [ -> ]Check with Ford as some of these were victims or bad air cleaner/piping resulting in dusting/early engine failures.

Interesting. The engine actually had a "full overhaul" by Rush Truck Center in 2017 per their receipt. This was before I was with this company. Rush now is saying no warranty exists and Cummins says the same. I can't imagine what causes an engine to self destruct at 100k miles, so I'll check in with Ford.