"Poor DEF QUality Detected" now what

ironpony

Professional Pot-Stirrer
Supporter
Def is injected into the decomposition Tube where it passes thru a mixer plate and into the SCR Catalyst. This all happens down stream from the DPF, initially if you have a Freightliner product there is a def quality sensor in the Def Tank on 2013 and newer models and the wiring to it is common to corrode. Also the inlet and out let Nox sensors take readings and can throw this code in a truck without the quality sensor and that can be caused by the list of other problems I gave, not necessarily buying bad def but, it can be contaminated by other things. There is a metal coolant tube that runs through the tank to keep the def fluid in winter. They are prone to cracking. Leaking def injector causing def to crystallize on the mixer plate is the third most common.
I was told a little compressed air is used to inject the DEF, and moisture in your air tanks can promote DEF crystalization. Yes or no?
 

r3gulator3

Friendly Neighborhood Former Technician
Supporter
I was told a little compressed air is used to inject the DEF, and moisture in your air tanks can promote DEF crystalization. Yes or no?
Moisture in the tanks on an air operated system will clog the regulator to the def injector and cause one of two things. A leak at the nozzle resulting in crystals forming in the decomp tube, or a def injector that doesn’t fire at all. Freightliner/Detroit went away from this system in 2014 and went to an electric fired def injector like Cummins had been using for years. The system is a lot less problematic than the air systems were, because most drivers/companies don’t maintain their air systems properly changing the cartridge annually and draining tanks daily.
 

r3gulator3

Friendly Neighborhood Former Technician
Supporter
DEF is injected in a catalytic converter after the DPF to diminish formation of NOX - it doesn't add to the backpressure on the engine exhaust like soot contamination in the DPF. AFAIK, we wouldn't even know it was there except for all the extra software and hardware added after Navistar/International started whining about everyone else's approach to NOX suppression after they realized that the MaxxForce engine wouldn't come close to meeting EPA 2010 targets.
Fun fact: international sued the EPA over emissions technology. The epa got 10 engines from them tested them they all fail (international claimed their ICT maxxforce technology was 100% compliant 100% of the time and others requiring fluid that could run out were not) and international had to pay a $2000 fine for every engine produced from 2010-2013. They also had to get some kind of credit on every truck to the customer too. International fired that CEO and replaced him with a guy named Tim Toole. Anyway that’s why international now comes with a Cummins engine hahaha!
 

ironpony

Professional Pot-Stirrer
Supporter
Moisture in the tanks on an air operated system will clog the regulator to the def injector and cause one of two things. A leak at the nozzle resulting in crystals forming in the decomp tube, or a def injector that doesn’t fire at all. Freightliner/Detroit went away from this system in 2014 and went to an electric fired def injector like Cummins had been using for years. The system is a lot less problematic than the air systems were, because most drivers/companies don’t maintain their air systems properly changing the cartridge annually and draining tanks daily.
Prime cautioned their drivers to purge air tanks daily a ways back, so it's nice to have that confirmation. mndriver mndriver and some others (myself) were discussing air system maintenance some time ago, and it was mentioned that replacing the whole air drier was about the same cost as just replacing the cartridge. I purge my tanks daily on pretrip. It's only few seconds for something that can prevent a lot of headaches and expense.

Fun fact: international sued the EPA over emissions technology. The epa got 10 engines from them tested them they all fail (international claimed their ICT maxxforce technology was 100% compliant 100% of the time and others requiring fluid that could run out were not) and international had to pay a $2000 fine for every engine produced from 2010-2013. They also had to get some kind of credit on every truck to the customer too. International fired that CEO and replaced him with a guy named Tim Toole. Anyway that’s why international now comes with a Cummins engine hahaha!
Along with all the lawsuits over MaxxFarce in general.
 

r3gulator3

Friendly Neighborhood Former Technician
Supporter
Prime cautioned their drivers to purge air tanks daily a ways back, so it's nice to have that confirmation. mndriver mndriver and some others (myself) were discussing air system maintenance some time ago, and it was mentioned that replacing the whole air drier was about the same cost as just replacing the cartridge. I purge my tanks daily on pretrip. It's only few seconds for something that can prevent a lot of headaches and expense.
Depends on the dryer. If you have an older canister style AD-9 or AD-4 then it’s always cheaper in the long run to hang a reman complete unit. On the newer ones with a spin on cartridge. If you lube the threads and o-rings when you install it and you do it annually and don’t muscle **** the cartridge on. Then replacing the spin on is the way to go.

If your finding moisture beyond the wet tank then you should check the wiring and function of the heating element in the dryer. If it’s a dark color and thick. Your compressor is passing oil.
 

quillcom

Well-Known Member
Def is injected into the decomposition Tube where it passes thru a mixer plate and into the SCR Catalyst. This all happens down stream from the DPF, initially if you have a Freightliner product there is a def quality sensor in the Def Tank on 2013 and newer models and the wiring to it is common to corrode. Also the inlet and out let Nox sensors take readings and can throw this code in a truck without the quality sensor and that can be caused by the list of other problems I gave, not necessarily buying bad def but, it can be contaminated by other things. There is a metal coolant tube that runs through the tank to keep the def fluid in winter. They are prone to cracking. Leaking def injector causing def to crystallize on the mixer plate is the third most common.
Ok, great fyi. Thanks for the info.
 

quillcom

Well-Known Member
There are several things that can cause this, bad sensor, a coolant leak into the tank, yielded or corroded terminals at the plug on the top of the def tank. Bad wiring, crystallized def in the decomp tube or One Box depending on if Cummins or Detroit, a leaking def injector,
Or overfilling my def tank, which I was notorious at doing, and I hear you should not do. I use to try to fill it normally only to see that needle not quite all the way over.
 

quillcom

Well-Known Member
Dude, there's no connection between the SCR/DEF and your DPF. They're unrelated emissions system.

Interesting article though. If you're concerned about DEF quality, it would be an idea to carry a small, empty glass jar to dispense a sample of pump DEF to inspect before filling your tank.
Upon further study I have to defer to your stance that yes dpf is not dependent on def or visa versa. Yes their only relation is that they are a part of EATS... which I was quickly reminded of today as I went to shield the sun from my eyes...............

49972

So I think the contaminated def came from me constantly overfilling the tank which they tell you no to which let in outside particles into a very sensitve system. Thanks buddy for the good info here.
particles
 

r3gulator3

Friendly Neighborhood Former Technician
Supporter
Or overfilling my def tank, which I was notorious at doing, and I hear you should not do. I use to try to fill it normally only to see that needle not quite all the way over.
If an over fill is doing it that leans me towards problems in the DEF header. The bad thing about over filling your tank is it has a tendency to wedge the float at the top of the tank and there fore causing the system to go dry. Lol. It’s not a traditional float like what’s in your diesel tank. Anyway glad you rectified the problem.
 

Ontario Outlaw

Hozer Witta Hood
Supporter
Upon further study I have to defer to your stance that yes dpf is not dependent on def or visa versa. Yes their only relation is that they are a part of EATS... which I was quickly reminded of today as I went to shield the sun from my eyes...............

View attachment 49972

So I think the contaminated def came from me constantly overfilling the tank which they tell you no to which let in outside particles into a very sensitve system. Thanks buddy for the good info here.
particles
The fuel guy will said to use a condom on your fill tube to help promote safe intercourse when filling, as it keeps the hole free from detritus
 
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