EGR failure on LLY

[johns d-max]

I put a MBRP catback on my LLY. At @12000 miles, the truck started smocking and would not go more that 10 MPH pulling out of a drive. NO Light. It did it again a month later, ten minutes of hell, then fine, no light. I did it three or four more times over the nect two months, no code thrown.Last time the truck was somking so bad that a cop pulled me over cause he throught it was on fire!!! Dealership said that it was EGR valve, replaced. Now no problems. They said that the Valve was full of chunks of carbon. I AM NOT running a cat. Do you think that this is why the valve got clogged up? Thanks

[More Power]

Excessive soot buildup could be due to the EGR valve remaining open more than it should. And yes, a stuck-open valve will cause the engine to smoke excessively. Kinda surprised it didn't set a code...

These engines run so clean that it should have taken a lot longer to reach a point of creating "chunks of soot" in the EGR valve assembly. Are you running a module or program that allows the engine to produce more black smoke?

MP

[DmaxMaverick]

That sounds absolutely dead-on for an EGR failure. The black smoke is due to the turbo not being able to build pressure, which overfuels the cylinders. The EGR is just a wastegate that dumps the exhaust gas into the intake. Soot chunks wouldn't take long to build up under those conditions. That's great you got it diagnosed and fixed in short order. Driving it extensively like it was could cause permanent damage, but doesn't sound like you did.

[johns d-max]

the truck did throw a code, but the light did not come on since it did not happen two times in a row, which is required. No Modeule. I did not drive it much that way, but if there were damage, what would the valve sticking open cause?

[DmaxMaverick]

Soot is abrasive, and retains heat. It can also restrict the intake path to the point of depriving air needed to keep EGT's down. Your running wasn't near enough to cause permanent damage. This would have to continue for an extended period of heavy use, like a long trip involving long grades and a load. The soot would have a chance to build up, then get worse, exponentially. The more soot you have built up, the worse the conditions are that cause the soot....Snowball. Don't worry about it.