Engine Temps Rising Again Update

[Gary M]

Update on Temps rising again!!

Before I left Vegas this morning, I crawled underneath to check on some of the ideas from my fellow Monaco Owners. I think I found part of my problem. In between the fan housing and the radiator, I removed a large amount of plastic that is used when service people need to enter your coach. It’s placed on the floors so as not to dirty your coach. I noticed a small piece stuck to my tow hitch. Pulled that off and noticed another small piece sticking out between the radiator and the fan housing. I pulled, and pulled, and pulled, and pulled till I had a 24” x 48” piece. I’m pretty sure its from almost a year ago when I broke down and had my VGT actuator was replaced. Temps were much better from Vegas to Desert Hot Springs today. Not perfect, but much better. But I think soon, new thermostat, new flush and fluid, new temp sender and anthing else you people( guys and gals) might recommend. I did finally receive my ECM file of which I sent to Frank McElroy and was sent back to me as a PDF. He commented on the high temps are preventing my Regens from completing. Because my coach has been running hot ( as high as 239) my regen is not completing. Last Regen was over 140 hrs ago. I had hoped the trip from Vegas that the regen would start and complete, but no. Ive already spent $1500 on a DPF and DOC filter cleaning and dont want to do it again. 
Thankyou for all your suggestions.  If you have more, hit me with it.

[Frank McElroy]

Actually the ECM printout I sent you was very revealing. It's great that Cummins gave you the EIF file.  I loaded that into the Cummins Insite software to generate the report.

If you are running hot and the dpf light is coming on but going off like it was in your case, also with a periodic Check engine light, the engine wanted to do a DPF Regen but couldn't because the engine was already running too hot.  High engine temps and a check engine light will shut off the DPF Regen.  In your case, you had 8 normal 100 hour engine run time DPF regens.  Then you started overheating and went for 150 hours before a DPF Regen with filter pressures double a normal Regen.  That's why the engine derated and the Cummins shop had to do a forced Regen. 

It's great to hear you found the reason for the overheat condition.  Now the DPF should Regen normally.

So, the lesson learned is to fix an overheating or check engine problem really soon because either one will tell the engine computer not to do a dpf Regen. 

Then it's just a matter of time before the DPF plugs and your engine derates.

[Scott 61]

Question for Frank you said in a  earlier post that your coach will not do a regen if you are in (cruise control) ???

Thank you safe travels

[Gary M]

1 hour ago, Frank McElroy said:

Actually the ECM printout I sent you was very revealing. It's great that Cummins gave you the EIF file.  I loaded that into the Cummins Insite software to generate the report.

If you are running hot and the dpf light is coming on but going off like it was in your case, also with a periodic Check engine light, the engine wanted to do a DPF Regen but couldn't because the engine was already running too hot.  High engine temps and a check engine light will shut off the DPF Regen.  In your case, you had 8 normal 100 hour engine run time DPF regens.  Then you started overheating and went for 150 hours before a DPF Regen with filter pressures double a normal Regen.  That's why the engine derated and the Cummins shop had to do a forced Regen. 

It's great to hear you found the reason for the overheat condition.  Now the DPF should Regen normally.

So, the lesson learned is to fix an overheating or check engine problem really soon because either one will tell the engine computer not to do a dpf Regen. 

Then it's just a matter of time before the DPF plugs and your engine derates.

I was hoping it would do its thing on my 6 hr trip. But nothing. Temps were between 181 and 188 coasting flat and downhill. There is a long stretch from lower desert to upper desert and it never got over 199. If I let the RPM’s get down to 15-1600, it would quickly rise to 94-99. It hit 205 once when I wasn’t paying attention to grabbing the gears.

Im here for 4 months now. I hope heading to Oregon will generate a Regen.

[Frank McElroy]

On 10/2/2021 at 11:42 PM, Scott 61 said:

Question for Frank you said in a  earlier post that your coach will not do a regen if you are in (cruise control) ???

Thank you safe travels

The engine WILL do a Regen if you are using cruise control.

The engine will NOT do a Regen under certain check engine light conditions, and will suspend a Regen if the engine brake is active, or if climbing a hill under full load, of if the speed drops below about 40 mph.

If the dash DPF light comes on, drive the coach at highway speed, say 60-65 mph and in 30 minutes the light will go off.  If the light comes on and you are at your destination, don't worry. On your next drive on the highway it will complete the Regen.

[Frank McElroy]

21 hours ago, Gary M said:

I was hoping it would do its thing on my 6 hr trip. But nothing. Temps were between 181 and 188 coasting flat and downhill. There is a long stretch from lower desert to upper desert and it never got over 199. If I let the RPM’s get down to 15-1600, it would quickly rise to 94-99. It hit 205 once when I wasn’t paying attention to grabbing the gears.

Im here for 4 months now. I hope heading to Oregon will generate a Regen.

Based on the ECM report from Boise at about 57,000 miles, you had a forced DPF Regen and a DPF reset when you had the VGT turbo replaced at about 52,000 miles.  Under normal conditions, driving say an average of 50 MPH, you should see the next 100 hour engine run time Regen at about 62,000 miles.  So I'd say from Boise you will likely need to drive another 5,000 miles before seeing another DPF Regen.

It looks like removing the material blocking your radiator has likely solved your overheat problem.  As long as Max hill climb temp stays below 220 it won't log an engine derate.

One thing for sure - from the Boise Cummins ECM file, you learned a lot about the DPF Regen history on your coach engine.