Dtc p042e

[MullenaxM]

would someone please tell me how a K&N filter could possibly cause an EGR Valve to stick???? This thread is soooooo far off the problem I can't believe it.

To answer your question,and to not slam the K&N air filters, Its not so much the air filter itself that causing the EGR valve to stick. As I'm sure that we all know by now that the issues that cause the EGR valve to stick is the soot in the exhaust gases that contaminates the valve faces and shaft inside the EGR valve.



What I have found is that the oil in the aftermarket air filters actualy get on the MAF sensor and coat it with a film of oil and inturn cause the MAF sensor to return inaccurate voltage signals to the ECM. This voltage signal is interpreted by the ECM to determine the Mass of air that is coming into the engine. It uses this information to determine how much EGR gases it needs to inject in the intake air stream to control the combustion temperature in the piston cylinder to reduce NOx gases in the exhaust system.



Without getting into a discussion about how a MAF sensor works, suffice to say that the oil coating the MAF sensor is causing the MAF sensor to return a voltage signal to the ECM that there is more air coming into the intake system than actually is. So inturn the ECM adds more EGR gas to the intake air than is actually nessasary, which inturn causes more soot in the exhaust gases which creates all kinds of problems.



As far as a repair goes, if you were to pull the MAF sensor out and clean it, it would be good until it gets coated again. I have been unable to determine if the problem is because the owners are adding too much oil to the air filter when they clean them or if it is just the filter itself letting the oil get into the system.



I'm not going to get into the debate as to weather the aftermarket air filters are any better than the OEM air filters, Being a dealer technician I personally recommend a OEM air filter, weather it be a MOPAR filter or a FLEETGUARD filter.



Mike

 

[MullenaxM]

One more thought, The main objective of any air filter is to filter the air coming into the intake system and remove any dirt or dust particles. No matter how much any aftermarket air filter manufacturer claims it will increase horsepower, if it dosen't properly filter the intake air, In my opinion your wasting your money.



Any air filter made can only hold a determined amount of dirt or bebris. Once it reaches it's capacity one of two things will happen :



1) It will stop up and not let any air through.



2) After it reaches it's capacity it will stop filtering the dirt and debris and let it just pass through.



Of the two choices from above I would prefer the 1st one because if the filter was to stop-up it would cause the engine to not have the power it would normally have and more than likely the owner would bring it in for service.



The problem we have with the 6. 7 liter engine is that the turbo will not be denied a source for air. On the 5. 9 liter engine once the air filter got to full capacity the turbo would try to eat the air filter (not a pretty sight), but on the 6. 7 liter engine the turbo has a optional source for air, it has the crankcase breather tube for a air source. So when the air filter starts to get stopped-up it will get it's air from the crankcase breather tube which in and of it's self can cause a whole bunch of other problems.



Mike

 

[DieselLady]

Thank you Mike. That was very informative. I personally Have vented my CCV to the outside for that and other reasons. I know, I know, Your not supposed to do that, but the reason I did, was not only did It let the turbo draw air, but it coats the whole intake system with oil. Including the grid heater. Then you add some soot. Yes, Tar and feathers. The grid heater will cook the oil and soot on to the grids and it becomes a big blockage. After only about 10k miles the blockage was substantial.
Thanks again for the info. I like the technical information as then each person can make their own decision as to how to solve the problem.

 

[PFranzese]

Mike,



I remember reading that 6. 7 has a warning to service the air filter. In your experience does this warning go off before the engine will start drawing to much air thru the crankcase and therefore possibly sucking oil in as well? Can you tell me where in the intake tube the MAF sensor is located?

 

[MullenaxM]

Mike,



I remember reading that 6. 7 has a warning to service the air filter. In your experience does this warning go off before the engine will start drawing to much air thru the crankcase and therefore possibly sucking oil in as well? Can you tell me where in the intake tube the MAF sensor is located?

There is warning that will be displayed on the EVIC (overhead console) along with one audible "Chime". In my experiance the perameters that enable the warning to be displayed are too high and the turbo will start sucking oil from the crankcase breather before the warning message appears on the EVIC.



The MAF sensor is located in the Air filter box top. right behind the intake pressure/temp sensor.



Mike

 

[PFranzese]

Thanks mike, thats good info to know. I will certainly keep an eye on the air filter and not rely on the overhead console to notify me.

 

[BDW]

Thanks for all the response and sorry it took so long to get back. So far, the dealer has warrantied everything and was just warning me. I cant afford the repairs on my own, so I will go back to an OEM filter for peace of mind.



Mike,

From what you have stated it sounds to me that coating the MAF would cause MPG to drop also, do you think this is correct?



Also, what would clean the MAF with?

 

[MullenaxM]

Mike,

From what you have stated it sounds to me that coating the MAF would cause MPG to drop also, do you think this is correct?



Also, what would clean the MAF with?

You would think that inaccurate voltage signals from the MAF sensor would cause a fuel mileage issues, but on the 6. 7 liter Cummins Diesel in the Dodge trucks only uses the MAF signal for EGR. The MAF signal is not incorporated into the fuel map algorithm.

 

[DieselLady]

You would think that inaccurate voltage signals from the MAF sensor would cause a fuel mileage issues, but on the 6. 7 liter Cummins Diesel in the Dodge trucks only uses the MAF signal for EGR. The MAF signal is not incorporated into the fuel map algorithm.

Ok, but the reality is, more EGR, Less fuel economy. So indirectly it does effect fuel economy.

Sorry to nit pick!

 

[MullenaxM]

Ok, but the reality is, more EGR, Less fuel economy. So indirectly it does effect fuel economy.

Sorry to nit pick!

Nit Picking is good, It keeps me on my toes.





If a diesel engine was to use an Adaptive fuel strategy like a gasoline engine that would be correct. But since the 6. 7 liter engine uses a fuel map algorithm, based on engine load,boost pressure,engine temp. etc... , the amount of EGR gases coming into the cylinder has no correlation to the amount of fuel that is injected into the cylinder.



This is the short answer, there's more if your interested.



Mike