Diesel Particulate Filter

[vap0rtranz]

I agree, it seemed odd to me as well. Could a screaming hot DPF have perhaps managed the heat, but something just past it couldn't? That is, the heat came from the DPF but hit the burning point on a connecter?

Like the DPF's own fuel line.

Supposedly the whole system has several sensors and computer to shut things down. On another forum, a guy replaced his truck's exhaust and found how many sensors are upstream and downstream.

And we're not talking just hot grill temps for a regen. I read somewhere that the temps shoot up to > 1000F.

[ajg617]

The SCR theory makes no sense. All that entails is DEF being injected into the SCR (selective catalyst reduction) This lowers NOX emissions. Since DEF is basically UREA which is pretty close to piss... It cannot increase the exhaust temp. It cools it. Now the DPF injects diesel into the exhaust to burn off the soot that clogs the DPF.(Think: burning off a grill)

That assumes that DEF was in the DEF tank. Anything else (like fuel) would certainly have an impact. And just FYI, we stopped at a Pilot station last year where all the DEF pumps were compromised in the truck lanes and staff was out warning everyone not to pump DEF. Seems the delivery driver was new, got confused, and put fuel in the underground DEF fill. It was only noticed because of the broken down big rigs lined up trying to exit the fuel stop. There's also a post on the Cummins Forum by a dealership of two trucks coming in with DEF tanks filled with gasoline.

[TimtheToolMan]

OP--during failure was there a pop sound or did exhaust get much louder at any point? I am wondering if the excessive exhaust pressure blew off the DFP or other part of system.

If engine had excessive oil before, wouldn't it still have too much after fire but not as much? Was the oil level checked after failure?

Leaking fuel filter (my previous comment) would not explain the sudden increase in DPF level.

[huntindog]

That assumes that DEF was in the DEF tank. Anything else (like fuel) would certainly have an impact. And just FYI, we stopped at a Pilot station last year where all the DEF pumps were compromised in the truck lanes and staff was out warning everyone not to pump DEF. Seems the delivery driver was new, got confused, and put fuel in the underground DEF fill. It was only noticed because of the broken down big rigs lined up trying to exit the fuel stop. There's also a post on the Cummins Forum by a dealership of two trucks coming in with DEF tanks filled with gasoline.

This is one of the reasons I only buy sealed jugs.

[wrp75_CO]

Same, I only used DEF from the jugs we get at Costco/Wal-Mart/gas stations, etc. I suppose it's possible for one of 'em to be bad, but every time I loaded the DEF tank recently it sure looked like water going in (no odd smells or other indication of polluted DEF.)

And I didn't see any evidence that parts were blown off the truck as I was driving. The DPF and SCR were still attached when they were looking at where the fire started.

[ajg617]

Same, I only used DEF from the jugs we get at Costco/Wal-Mart/gas stations, etc. I suppose it's possible for one of 'em to be bad, but every time I loaded the DEF tank recently it sure looked like water going in (no odd smells or other indication of polluted DEF.)

And I didn't see any evidence that parts were blown off the truck as I was driving. The DPF and SCR were still attached when they were looking at where the fire started.

I'd be more concerned about what might have gone in while it was at the dealer and out of your control. The amount of damage done to vehicles at dealerships and independent repair shops has been an increasing problem.

[Butcher]

The regen process evidently sprays fuel into an exhaust chamber to do a "controlled" burn of the exhaust cruft.

That is not how it works. There is no fuel sprayed into the exhaust.

Knowing that the DPF is ceramic insides and high temp metal on the outside, I highly doubt if the DPF caught fire. It could be that the part got so hot that other items around it caught fire, but even that is doubtful.

[Butcher]

I am wondering if the excessive exhaust pressure blew off the DFP or other part of system.

A 100% plugged DPF causes the engine not to run. Remember the potato in the tail pipe trick? Same thing.

[Butcher]

Dealership way over filled the crankcase with oil. Running the engine caused atomization of the oil which overwhelmed the PCV (hmm, that was worked on as well). This lead to motor oil being introduced into the combustion cycle which will clog a DPF rapidly. Then the emission controls started a regen cycle to clean the DPF which introduced fuel oil into the DPF. With all that fuel in the DPF (motor oil + fuel oil) I can easily see how the DPF would catch fire internally.

That is not going to happen either.

[Butcher]

Although the dealership may be at fault, just because they worked on it does not automatically mean it is.

The insurance company will invest the right time/money to investigate this. I suspect the fire department will too. If there is enough evidence of what exactly happened, the blame will be passed to those that cause it. If you think they are going to listen to the truck owner, I think not, unless you have some cred.

The only thing for certain as long as we keep pushing the government for clean air, the government will push the manufacturers to make that happen. Just like the cars in the 70-80's, the emission controls were terrible and cars ran terrible. It took some time, but they did a pretty darn good job to make tons of power and clean tail pipe emissions. If you think the manufacturers know the long term durability of diesel emissions, I would recommend you change that thought. The long term durability is happening now with the clients.

Just wait, batteries are around the corner and if you think diesels have problems........