Regeneration Frequency Issue: MAF Poll

[Ostracize]

My dpf guage was @ just above the first hash mark before everything and is still in the same spot. Previous regens were every ~3-350mi and my trip B used to track is at 195 currently now after cleaning and test loop. So now just going to monitor and see if it helped.

 

[OLEJOE]

I’m interested to see if the relearn has any effect. How many miles on the nasty sensor?

 

[AH64ID]

I’m interested to see if the relearn has any effect. How many miles on the nasty sensor?

The relearn is for the MAF, so the cleaning probably won’t have any effect on that. The MAP only has to read pressure and temp, so it’s not a big deal if it’s dirty and why it survives on the downstream side of the EGR.

 

[OLEJOE]

The relearn is for the MAF, so the cleaning probably won’t have any effect on that. The MAP only has to read pressure and temp, so it’s not a big deal if it’s dirty and why it survives on the downstream side of the EGR.

My MAP was just as bad and I cleaned & didn’t have a regen for 10 days , prior was every day !

Evidently it getting dirty does have some effect on it. Cleaning it seems to have an effect also.

 

[Ostracize]

The MAF and MAP work together specifically in turbo applications to accurately inform the ecu to determine when the ignition(for diesels, injection timing) should occur under varying engine load conditions. I have my theory as to why a MAF relearn plus cleaning can have an effect overall... Which is what I'm hoping to see.

I’m interested to see if the relearn has any effect. How many miles on the nasty sensor?

Hard to say exactly... I started seeing regens more frequent than 24hrs about 7/8 months ago... But there were also other variables in the same frame of time... Had the ecu flashed by dealer to address 2/3 flare... And I unknowingly installed the "wrong" intake filter (which has been corrected for about 3 months now.

 

[mbarber84]

Did they do the MAF reset procedure @mbarber84 posted previously? If not, it may be going off the old lookup tables.

I am going to try to do that drive sequence today and see if it’ll reset even with the “bad” MAF. Hoping it will revert like it was new and take a while to learn the bad behavior.

Was going to say the exact same thing.

@scdo if they didn’t perform the MAF relearn after replacing the sensor, I wouldn’t place too much validity in the results. The document is pretty specific in what it outlines:

“Anytime the MAF or air filter is replaced (due to incorrect part), the MAF has to relearn similar to a transmission.”

 

[OLEJOE]

I think you might have the answer. “Dealer flashed the ECU”.

 

[AH64ID]

Evidently it getting dirty does have some effect on it. Cleaning it seems to have an effect also.

Just looking at what each sensor does for operation. MAP is for fuel delivery, and MAF is for emissions.

Electronic diesels all have MAP’s, but only those with EGR have a MAF.

The MAF and MAP work together specifically in turbo applications to accurately inform the ecu to determine when the ignition(for diesels, injection timing) should occur under varying engine load conditions. I have my theory as to why a MAF relearn plus cleaning can have an effect overall... Which is what I'm hoping to see.

I’ve only seen MAF in diesel applications with an EGR.

 

[OLEJOE]

We may never find out what the root cause is. The ones saying don’t know and the ones that know (if any) ain’t saying. I’ve got a better, more knowledgeable Service Advisor at a different dealership I’m dealing with now and I’m going to see what he knows or hears about this. He’s been great so far and I hope it holds out. I saw the most improvement by changing the brand of fuel I use.

 

[Ostracize]

Just looking at what each sensor does for operation. MAP is for fuel delivery, and MAF is for emissions.

Electronic diesels all have MAP’s, but only those with EGR have a MAF.



I’ve only seen MAF in diesel applications with an EGR.

That is probably true and I don't doubt you... I see it much like(similar to) narrow vs wide band o2 in NA vs FI applications. Basically needing more fueling delivery data for....
Egr diesels - to make power with while meeting epa requirements.
O2/FI wide band - to make power while avoiding fuel knock during varying engine loads

 

[DougB]

Last week I cleaned my MAP sensor and adjusted oil level but didn’t notice any change in regen immediately after. Probably because the MAF tables were the same? Dunno. MAF sensor was perfectly clean as I’d expect. I have the German version.

Changed the oil today from 10w-30 to 5w-40 at just under 6k. Will send off for analysis. Put in 11qts. Looks to be about middle of the SAFE on the dipstick.

Did the MAF relearn sequence,too, as best I could. FRP varied from 15-21k over the 3 drive cycles but I kept it at ~2600, 68mph in 4th, the entire time. There’s not much perfectly flat around central Texas. I’d have to go further east but risk having to slow down for lights in small towns.

While doing the drive cycles the DPF EVIC never got off 0. The iDash started at 15% and I think it’s still under 30, don’t recall at the moment. It got as high as 47 during the drives but after the 10mins key off it would be in low 20s when restarted. The EGT 2&3 we’re around 550-575 during the drives. Rarely saw either over 600 except on a couple hills. Have about 110mi since last regen with about half of that highway miles. Different miles than my normal DD routes.

I’ll be taking it on a highway road trip next week so hopefully the MAF will learn during that trip. Expecting it’ll passively regen, too.

 

[OLEJOE]

Last week I cleaned my MAP sensor and adjusted oil level but didn’t notice any change in regen immediately after. Probably because the MAF tables were the same? Dunno. MAF sensor was perfectly clean as I’d expect. I have the German version.

Changed the oil today from 10w-30 to 5w-40 at just under 6k. Will send off for analysis. Put in 11qts. Looks to be about middle of the SAFE on the dipstick.

Did the MAF relearn sequence,too, as best I could. FRP varied from 15-21k over the 3 drive cycles but I kept it at ~2600, 68mph in 4th, the entire time. There’s not much perfectly flat around central Texas. I’d have to go further east but risk having to slow down for lights in small towns.

While doing the drive cycles the DPF EVIC never got off 0. The iDash started at 15% and I think it’s still under 30, don’t recall at the moment. It got as high as 47 during the drives but after the 10mins key off it would be in low 20s when restarted. The EGT 2&3 we’re around 550-575 during the drives. Rarely saw either over 600 except on a couple hills. Have about 110mi since last regen with about half of that highway miles. Different miles than my normal DD routes.

I’ll be taking it on a highway road trip next week so hopefully the MAF will learn during that trip. Expecting it’ll passively regen, too.

Look forward to hearing how it pans out.

 

[batman900]

Can't vote twice but confirmed my father's 2023 with the issue has the China sensor. His will sometimes regen 10-30 miles after the last one, it's pretty bad. He tows a lot and only has around 4k miles on the truck. Dealer said mid Feb before they can look at it which is insane to me but he does live near Austin TX, lots of people around there.

 

[CdnHO]

No issues with my 2021 HO with a German MAF sensor. I did take the precaution of removing the Mopar air filter (with the glue strips) with the proper Fleetguard about three months ago. About 60% of my miles is towing heavy. The rest is around town sort of stuff.

 

[scdo]

You know, I’m not sure but STAR advised them the fix didn’t work. It couldn’t hurt for me to try that procedure myself.

I tried the procedure myself. It did not make a difference. Next two regens came only about 35 miles apart.

That said, I finally had a chance to tow a ~ 8,000 pound TT. When towing, the DPF gauge sits confidently at 0%. I’ve driven 500 miles while towing so far and it doesn’t budge at all.

 

[ironmike]

Here's another update to the initial cleaning of the severly sooted up MAP sensor,12/11/23, after having regens every day prior. I have had only 1 regen now for the last 17 days. I have put approximately 300 miles since MAP cleaning. I have watched the DPF gauge toggle up to less than 1/2 then back down to zero a few times.
I'll try and start to log miles, date, time, the next regen cycles to get some data... Seems to me the proof is cleaning the MAP sensor. I did nothing else to the truck but visually check the other 2 sensors on air filter box top, which were perfectly clean

 

[OLEJOE]

Looks like your regen frequency has improved. Continued driving may help it clean itself out and may improve more. Mine was regening every 3-400 miles and 10-14 hours. What ever it was it went to 24-25 hours. 1103 miles on 1 and 896 on the next one. I currently have 510 miles and 13 hours since the last one but my gauge jumped up to about 3/16 or 18.75% yesterday but I have been making a lot of short trips over the holidays. Good luck with yours. I hope you are on to something. I think they have changed the emissions requirements and have increased the amount of EGR they are forcing these trucks to ingest. My truck uses hardly any DEF except when towing. It also doesn’t regen except every 24-25 hours towing.

 

[ironmike]

Looks like your regen frequency has improved. Continued driving may help it clean itself out and may improve more. Mine was regening every 3-400 miles and 10-14 hours. What ever it was it went to 24-25 hours. 1103 miles on 1 and 896 on the next one. I currently have 510 miles and 13 hours since the last one but my gauge jumped up to about 3/16 or 18.75% yesterday but I have been making a lot of short trips over the holidays. Good luck with yours. I hope you are on to something. I think they have changed the emissions requirements and have increased the amount of EGR they are forcing these trucks to ingest. My truck uses hardly any DEF except when towing. It also doesn’t regen except every 24-25 hours towing.

I too also notice i am not using much def fluid in my opinion....

 

[AH64ID]

Looks like your regen frequency has improved. Continued driving may help it clean itself out and may improve more. Mine was regening every 3-400 miles and 10-14 hours. What ever it was it went to 24-25 hours. 1103 miles on 1 and 896 on the next one. I currently have 510 miles and 13 hours since the last one but my gauge jumped up to about 3/16 or 18.75% yesterday but I have been making a lot of short trips over the holidays. Good luck with yours. I hope you are on to something. I think they have changed the emissions requirements and have increased the amount of EGR they are forcing these trucks to ingest. My truck uses hardly any DEF except when towing. It also doesn’t regen except every 24-25 hours towing.

I not sure what timeframe you are referring to with the changed emissions requirements, but the 19+ trucks use less EGR and more DEF than the 13-18 trucks.

What kind of DEF mileage do you get?

And since this is a regen thread I want to point out that DEF/EGR don't have anything to do with regen or DPF.

 

[OLEJOE]

I not sure what timeframe you are referring to with the changed emissions requirements, but the 19+ trucks use less EGR and more DEF than the 13-18 trucks.

What kind of DEF mileage do you get?

And since this is a regen thread I want to point out that DEF/EGR don't have anything to do with regen or DPF.

Correct. DEF is used in the exhaust to convert the nitrous oxide produced by the heat. EGR is a means of lowering cylinder temperature to reduce nitrous oxide emissions. If the cylinder/exhaust temperature is lowered in the engine, then there is no need for DEF except for when it is regening or under high boost/load conditions when turbo boost cuts down on the amount of EGR because of high intake pressure. The time frame I’m referring to is 2022 or late 2021.
My 2018 used twice as much DEF as the 2022 is using and never had a regen problem regardless of the fuel or air filter used.