Check engine light and other observations

There have been numerous posts about what temps the Cummins ISL, both old and new, is suppose to run at. Some say they should run at 200 degrees to perform efficiently and make regens occur properly, while others have coaches that run at 180 all day.

I personally spoke to Cummins as my 05 Diplomat, with a 400 ISL, ran 180-183 all day long and would occasionally, on a hot day, hill climbing, go to 200.

My 2014 ISL 450 runs the same as my 05, 180-183 all day long. The only difference is that on a hot hill climb, it will only go to 195 (side radiator) and then come back down when the fan goes to high.

Many said this was wrong and I would never regen properly. I spoke with Cummins and after several minutes of telling him his stock answer was not answering my question, he finally understood that I was looking for the correct temp to cause a regen to perform properly. He admitted that he didn't know the answer and would get back to me. To my surprise he called me back a few days later. He spoke to the techies and they told him the following.....a Cummins engine will regen at any temperature from a cold start to about 205-210 degrees. To me, cold temp included anything above about 165 degrees.

So....the answer is.....the ISL can run all day long at 180 degrees without any detrimental effects. Since I've had two that run at that temp and know many others that do, I don't see any issues with it running cool. I don't baby my coaches and run them hard. My new coach just turned 20K and has never regened.

I would have to see some proof that running hotter would improve performance and mpg and that all of the coach manufacturers, who are specifying that their coaches be set up to run 180, are wrong.

"bullydogs1'....If you want to unleash that beast, add the Source Engineering rear radiator engine fan (25HP returned to the engine- $600.00) and the Parleys Diesel DIGI CR chip, an addition of 52 HP - $600.00. The two will increase your climbing substantially and will add between 1/2 - 3/4 mpg.

179F is cooler than any of my diesel is advised to run, so I would check that with engine manufacturer.
When I tend to agree to not loose a sleep over CEL for few seconds, I don't believe in things fixing themselves and would read stored codes.
Motorhomes are behind in technology, so the computer might not have the memory, but driving with OBD under the seat, if not ScanGauge plugged all the time would be in my books.

Looking at the digital PSI screen is how I noticed that...again me being just nuts and as for your monster fan..did you see Sylvie when that kicked in?..she jumped 10 feet away...ever see a bulldog jump 10 feet?? When we left, I was hooking up the toad and Sierra decided to sit on the acc pedal of the coach...I was just doing a final walk around and I thought the engine fan was going to a higher speed, then I heard it rev up more, then Stella ran from the back of the coach and I ran from the toad to the coach to see what was happening and there was Sierra smiling with her rear on the pedal while Stella was securing the inside and I was securing the outside...wish I had a video of that....

Bullydogs.... I, too, agree that the check engine light is nothing to worry about. It could be a sensor that had a temporary information failure, then kicked in.

Your engine runs cooler than ours. If I don't have the dash air on, the radiator temp is about 210-212. If the 'monster' fan is on with the dash air, it will be about 180-185. Remember the monster fan?.... it will pull leaves off the ground.

If you are reading your air gauges from the dash (analog), they are really close 'estimates', if you go through the digital read-out, those are accurate. Which ones are you looking at?

MM.

Thanks DSDP Don for the reassurance..it is due for an oil change, fuel filters change and a gen service...once I take care of a popped door awning, I will be getting a service done anyway...It may also be due for a regen , which happens about once every 6 months anyway and last one was early November (can you tell I watch everything ???) but it is running like a champ getting 8.5 mpg pulling the toad going at 63 mph and 1500 rpm...

Yes....you're worrying too much. Your ISL is running exactly like it should regarding temps. Your check engine light can be associated with several things, including fuel filters, coolant level and on some, even the level in your window washer fluid.

I wouldn't give that momentary CEL another thought, especially since there were no codes.

If it's been awhile since you changed fuel filters, that might be something you want to look into.