2018 579 Peterbilt X15 Cummins Constant Regen

2018 579 Peterbilt Had engine light come on monday morning while it was idling to warm up for the day. Truck since then would regen anytime I come to a stop sign or anything to do with slowing down where rpm got under 1000. Engine light went away around 11am and turned back on shortly until 4:30pm and shut back off. Took truck in and had fault code 3725. They replaced inlet nox sensor. Went to pick up the truck and when I turned the key the ignition was just clicking and the bunk alarm and espar heater was turning on and off. When the key was turned there was no power to the truck at all. Hooked up battery cables and did nothing. Mechanic did something with the battery cables and got it started. I noticed today that when I left the shop and was coming to a stop sign it started to regen. Here’s the kicker. I pull into the farm as it starts to regen because I’m slowing down and got parked, if I idle it up to 1000 and then cut the cruise it will stop the regen. If I idle it up a notch to 800 it starts to regen. Idle back up to 1000 and cut the cruise it stops the regen. So truck normally idles at 700. If I bump it up to 800 it starts a regen and can stop it by putting it up to 1000. Whenever I do idle I’ve always idled at 900-1000 and never had this issue. It sounds like where the egr cooler is it makes some sort of leaking noise and told that to the shop and they said they couldn’t find a leak there and what I’m hearing it the exhaust going through egr valve when it opens. But it seems I can hear it at all times. And while it regens it sounds more like a ticking noise. I don’t have access to insite so I’m very limited to what I can see. I have geotab to track ifta and that will show engine codes but not really live data other than a few things ( Temps and fuel consumption ) anyone here anything like this ?

 

I think so it hasn’t come back on. I think I might have spot something on the manifold which I mentioned to the shop. They said they sprayed it down several times and it wasn’t leaking but in a few minutes I’ll take a picture and upload it

 

Pictures

 

First one is bottom of #5 and 2nd one is #6

 

Top between #5 and #6

 

Also my stack has this brownish dust type film on it. Not sure what exactly going on with it . It’s always just a dark gray color. But never a coating of something else

 

I gotcha. I just didn’t know if the black between #5 and #6 would be an indication of a leak