Volvo VN/D13 issue

Finally got a chance to work on that truck. Top of the DPF was caked with a thick layer of fibrous material, almost like insulation. Truck only has 350 miles since DPF/DOC change. Could the DOC be deteriorating?

 

Has the DOC catalyst shifted back/moved? Sounds like damaged DOC or DPF. Is it a sandy like failing catalyst or the insulation material that surrounds the catalyst? Pictures help.

 

I blew it all off before taking a pic like a dummy, it was an entire layer of what I'm assuming is the insulation for the DOC. It was a whiteish almost fiberglass like strand layer plugging the DPF, with a layer of regular soot on that. Did'nt have that tan/sandy feel at all. Came off like lint from a dryer trap

 

Sounds like you need a new DOC and the DPF cleaned again. Let us know how the Regen goes.

 

Check inside the flex pipe after the turbo. Volvo had a recall at one time because the insulation was coming apart inside and clogging filters.

 

Flexpipe looked good, I've had that happen before. Took the only other clean DPF/DOC we had, put it in. Inlet/outlet DPF temps are in the 875-905 degree range, smoking like a steam train, I'm assuming the SCR is finally getting some much needed flow/heat. No codes after regen... going to kick it out tomorrow and run it local for a day before scheduling an OTR trip. Thank you for the help guys.

 

Truck went out today for locals, 265 miles, left at 0% came back at 89% soot with a SCR inefficient code again. Driver reports truck runs great, occasional seems to have power loss when accelerating. He usually drives one of our KW's w/ a manual so I'm thinking some of his report is not really knowing the idiocracies of the iShift...

 

You can always do the "snap test" with pipe behind turbo disconnected to see if you are getting excessive smoke/overfueling cylinder, but findings are subjective. The way I do it with a Paccar is start a Regen to get the after treatment above 550 degrees F. Flip the Regen switch to disable and take a road test while monitoring before catalyst NOx sensor. Get it on open road around cruising speed and completely get out of throttle for 10 seconds. The NOx reading should be very close to 0 or at least below 10 PPM when engine is in overrun (zero fueling). Leaky injectors while still cause the NOx sensor to read NOx emissions. Not sure if you can do this with PTT, all Mack's I have still hook up with VCADS.

 

Also, Venturi pipe isn't getting excessively plugged from a sticky EGR valve?

 

Venturi was clean when I checked it yesterday, I'll try the rolling nox test you recommended tomorrow.