springerj10

It has the latest software updates.

1 hour ago, Onyx610 said:

This may be a stretch, but did you ever take notice to egr diff pressure during regen?

I don’t remember what it was at this time, I’ll check after the truck comes back in.

It is a Nox issue that is throwing fault codes and preventing the truck from being able to do a regen by the button and putting it into limp mode every couple weeks. There is no DEF build up. The Nox sensors have been replaced 3 times in the past 2 years with no change on the values. The Nox outlet has always read higher than the inlet.

20 minutes ago, fjh said:

(make sure you got proper temp ) what temps are you seeing?

5 minutes ago, fjh said:

Yup start at the other end! make sure you got proper temp ! Turbo spooling properly on regen ? Check turbo Effort possibly sticking ! fuel pressure OK? fuel dowser clean?Dpf sensor ports clear  tubes clear? with this junk you need to work front to back ALMOST always!

 

Just sayin

Turbo bearings went out about a year ago, had a new turbo and actuator installed. Fuel pressure is good. 7th injector is clean, gets replaced annually. DPF sensor ports and sensor are clean. EGR pressure sensor and ports are clean as well.

Got a 2018 Mack MRU with an MP7. Truck has had regen issues since we got it new, been to the dealership multiple times but Mack says they can’t duplicate the issues. 
 

Active codes as of right now.

P103C00 P20EE00 P046C64 P24F700

Truck is in derate requesting a Sulfur regen. During the regen the Nox inlet is at 1026 PPM and outlet is 1773 PPM.

It’s had the SCR box, DPF, DOC, DEF filter, DEF doser, DEF level sensor replaced.

Any suggestions on where to go next?

Ended up sending the truck to Mack, didn’t have the time to diagnose and repair it while maintaining all of our other trucks. It had 3 out of round cylinders. Mack did a full rebuild on it.

It’s actually a 2012 not 2011. GU713 roll off truck, 296000 miles on it. Power steering works fine. I’m using Tech tool. I’ll pull the gear out and check it. The truck originally came in requesting a regen with no fault codes. That’s when I put the EGR valve on because it wouldn’t get up to temperature. It regened after that.

I swapped the valve on the front left side of the head with one out of a running truck, didn’t make a difference.

Haven’t checked it under load but at wide open throttle it jumps up to about 90 PSI. During a test drive it will have an intermittent skip bad enough to make the truck surge.