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Gary.Jones · 09-04-2015, 09:04 PM

Chuck and Waterboy

Well, that definitely has not been my strategy on starting. I always put the coach in fast idle and it stays in fast idle for whatever time that it takes to get the toad connected. Actually, after a certain time, the Cummins kicks back out of fast idle and drops back to its normal idle rate.

I always idled my Dynasty like that and just continued to do that (but it did not have all the sophisticated catalytic / DEF stuff on it either. Never heard of heading out cold. I can do that if that really is the recommended strategy. Have others heard that from Cummins?

Gary

Ann n Gene · 09-04-2015, 10:10 PM

Yes Gary, Cummins does not recommend that you idle any more than you absolutely have to and that should be at fast idle. All this pollution stuff, especially DEF systems are very complicated, expensive and not completely optimized yet by engineers. They still are trying to figure out what the side effects are and how to deal with them. If they were medicine they would never have gotten government approval to come to market and these should not have either. All JMHO 🚌🚓

2016 Cornerstone 45B on order
Formerly 2011 & 2013 Anthems
2014 Lincoln MKT towed

brianw8602 · 09-05-2015, 07:29 AM

X2. That was the guidance suggested at the Spartan Academy.

757driver · 09-05-2015, 08:34 AM

Same here. From Mike O'Neil at Spartan, "Idle as little as possible and then only at high idle".

brobox · 09-05-2015, 10:22 AM

Gary, it was also in the Cummins manual. I actually read the entire CD.

jb4545 · 09-05-2015, 02:22 PM

I didn't have any excess idle time……..at least I don't think I did. I was busy gathering up for a trip and started/moved the coach 3 or 4 times for short distances. I was pretty busy and it could have idled for 10 or 15 minutes during one of my many trips to the garage.

We completed the first leg of our trip 256 miles and 7 hours on the road without a reoccurrence of the fault code. A good bit of that was stop and go getting out of Houston. We'll see how it goes on the return leg………..

Gary.Jones · 09-06-2015, 06:03 AM

John

I hope your trip is uneventful. I am delighted to say that we are 1800 miles into our current long trip and I have had no re-occurrence of "the code" or any major problem either. YAHOO!

Chuck and others: My idling is like Johns, usually 15 minutes or so while we connect the toad and/or get the cats into the coach as we are departing. Also, I have noticed no change in long haul truckers tendency to idle their diesels all night long at a truck stop or idle the engines while at a truck stop napping/fueling. If idling was a problem, they would be changing their behavior too and they don't appear to be.

Our coaches are a different breed, I understand. I am very reluctant to do no idling and simply fire up and hit the road full speed at first fire up. I will make some calls to Cummins and Spartan and talk to them to try get a more extended explanation of why they are recommending it. Do either of you guys know the logic / sorce of the recommendation?

Gary

YC1 · 09-06-2015, 06:26 AM

My recent expenisve encounter with the dpf filter indicated "high idle time". I too said no way. However, doing the math by adding the start up times, hook up times, leaving it run while fueling times, stop and go traffic times, and indeed it appears my idle time is around 15%.

That aside, the fix for my problem was replacing the dpf filter and probes as well as some ECM updates to change the regen parameters.

I have not traveled very far since the repair and have not seen a regen since. I have seen the regen light and high exhaust lights flash on and off for a second a couple of times but they did not stay on,

waterboy10 · 09-06-2015, 06:39 AM

I believe that the modern engine can be used as a start and go. There is no need to idle for a long time - at the Spartan Academy they recommended to not idle for long periods of time. Long idle times lead to DEF issues as well as codes according to Big Mike. Many trucker engines are not equipped with DEF (only newer models). I have had no issues with starting and going and it would be rare when I go from a start to full speed as the engine will warm up as I approach a major highway when leaving a camp ground. Just my opinion. How many people take the time to warm up their car before moving out of their garage for a trip? Is a RV any different - I think not. JMHO.

Gary.Jones · 09-06-2015, 09:18 AM

I'v seen many brand new Peterbilts and Volvos, current models, who idle their engines for long periods with no ill effects. My son drove a new model Volvo for Swift and they were encouraged to shut down and not idle long periods, but it had nothing to do with engine or exhaust issues, they simply wanted to eliminate the diesel consumption of long idles, even in the dead of winter in upper Michigan and had auto-start and auto-stop engine capability to maintain a cabin temp that was not freezing their drivers.

I believe our coaches and these engines rarely, if ever, do an active regeneration. I believe that our engines do what I know as a "passive regeneration". For us, this is almost always done simply by driving down the road. When my coach was in the shop for all this work, a standard thing that they did repeatedly was the "passive regeneration", and it was done by putting the coach on fast idle (~1000 revs) and letting it sit on fast idle for a full hour. The techs said that if the revs are at 1,000 or above, there is sufficient heat in the PDF to accomplish the regen, and driving down the road did it naturally.

I still would like to know what specific issue is complicated by a 15 minute idle. Is it soot build up (doubtful), or temp elevation and the ECM wanting to trigger an active regeneration, or whatever. I don't know and want to learn. I am a complete diesel engine newbie and would hope that one of you retired diesel mechanics or professionals can enlighten me.

Gary

brobox · 09-06-2015, 11:35 AM

Gary, I read about the extended idling and 16 DEF sensor that all need to talk to each other in the Cummins owners manual. I am only going by and passing along what I read in the manufactures manual. The long idle regeneration puts out 1800 degree temps that I am sure is going to affect the DEF sensors, maybe not, but why chance it?

If the people that went to the Spartan class are passing along the same information, and I have escaped any problems from "airing up, pull slides in, and go", I hope to continue to stay out of the shops with that method.

The Cummins manual was not bad reading, I learned a lot over my old 350 without a DEF system.

motorhomeguy · 09-06-2015, 01:29 PM

Gary, I would do as you indicate. Keep it idling until you get real real proof about the extended idling, like you said, you did it in your previous rig and never had a problem and the big rigs do it all the time. What do these guys know...

jondrew55 · 09-06-2015, 02:27 PM

Quote:

Originally Posted by motorhomeguy

Gary, I would do as you indicate. Keep it idling until you get real real proof about the extended idling, like you said, you did it in your previous rig and never had a problem and the big rigs do it all the time. What do these guys know...

I got stuck in traffic on I75 a few weeks ago for 7 hours. Couldn't just shut it down because we'd move 50 feet every few minutes. Couldn't pull on the shoulder and wait it out because emergency vehicles kept whizzing by.

As far as I can tell my coach is no worse for the wear for all that idling. I don't think starting and shutting down the engine a bunch of times would have been great either. I think the idea is just avoid idling whenever you can

Ann n Gene · 09-06-2015, 06:15 PM

I second that. My point is that I avoid unnecessary idling but use common sense. Starting a lot in short periods of time is hard on starters etc and each time there is some period, however short or long it may be, before oil is flowing through the the system. Again, JMHO

2016 Cornerstone 45B on order
Formerly 2011 & 2013 Anthems
2014 Lincoln MKT towed