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Idleing time


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I have heard that idleing you truck for extended periods is bad?? Well, I have a unique problem in that I work only about a half mile from where I live.. Morning temps are droping into the teens, and soon single digits.

 

I normally go out and strart the truck and let it run for about 15 mins, drive to work, and then let it run at least another 10 before I shut it off and go in... The high idle  stays engaged most of the time.. about 1050-1100 rpm

 

Which is worse,, start it up cold, and shut it down cold? or let it warm up as much as possible?

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Which is worse,, start it up cold, and shut it down cold? or let it warm up as much as possible?

You want to get your truck as warm as you can. Starting it up and shutting it down cold is real hard on not only the engine, but the rest of the truck too. Do you have plug ins at work? The more it is lugged in the warmer it will be.

 

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You want to get your truck as warm as you can. Starting it up and shutting it down cold is real hard on not only the engine, but the rest of the truck too. Do you have plug ins at work? The more it is lugged in the warmer it will be.

Well, I do plug it in religiously over night which helps tremendously in the morning, but its not practical to plug it in during the day.. I usually have to go out and check cows after work, 20 mile round trip, so its not such an issue in the evening.

Edited by angus
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As for me if I'm short tripping I will attempt to extend my driving time by driving past my stop to allow the engine to fully warm up.

 

hmm, I guess I could start hitting the doughnut shop on the other side of town in the mornings??

 

On the technical side though... What is Cummins issue with idleing?  The rpm on high idle is not that much lower than driving 55mph

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The biggest thing with idling them or any other diesel is that you do not get the cylinder temperatures high enough to completely burn all the fuel. That leads to cylinder wash down and accelerated wear for the cylinders, pistons, and rings not to mention the oil gets diluted with raw fuel.

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Would this be a good reason to run additives and boost cetane in the winter months??

 

I think my best option would be to get my other gas project running, and let the cummins sleep in the garage :burnout2:

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The best way to warm anything up is to drive it. Idleing does nothing but wear stuff out quicker and burn fuel. I start mine, wait until the heaters cycle twice and then idle up to 1200 with the cruise control. I then unplug the pickup, clean windows and do what needs done then leave. Most I will idle in high idle is 5 minutes. Regular idle is as little as possible. Cummins/dodge want less than 10% idle time. This is at 0-10% load which is anything under 1,000 rpms and vehicle in park. The cruise control high idle is 10-20%.

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Your application is one of the few times where Cetane boost would be a good idea. Cetane improves low temp/low load combustion, try a 3pt increase.

 

Fast idle does help increase load and improve combustion but your 25 minutes of fast idle for 1/2 mile of driving isn't the best option either.

 

Do you have a winter front? That will really make the block heater more effective.

 

There is more to get warm than the coolant and cylinder, the oil needs to get hot as well. 20 miles is probably barely enough to warm things up.

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Even my daily commute to work it would take at least 8 miles or so to reach full 190*F. I know the 1/2 mile trips to the fire station are rough. So when I'm done with my fire call I'll drive away from home another 5 miles and turn around to come home giving me 10 miles of operation time.

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Do you run a front cover, or a chunk of cardboard over the radiator? Perfect for the short hops.

What kind of fuel are you running; blended or winterized? Cetane should be UP in either case, I think I saw somewhere that #1 was 55 or 57 cetane? I remember #2 of having a minimum of 40 by law.

Then again, higher cetane means lower btu's.. or less heat. Probably a wash here..

I will guarantee, a gelled fuel system makes NO heat! :D

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I don`t have a winter front for my truck.  I`m pretty sure all the fuel sold around these parts is winterized #2..  My truck normally takes about 26 gals on fill ups, and I have been dumping about 16oz of howes diesel treat in. I have also upped the 2 stroke from 200: 1 to 128:1  just for winter.

 

Keeping the truck plugged in over night sure helps avoid the long defrost in the morning. and if I take the rather long way to work..(8-10 miles) its getting close to operating temperature.

 

Its strange because you could start the thing up and let it idle for hours and it would never reach operating temp, but once it warms up it will idle and maintain??

Edited by angus
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Most diesel will never move the temp gauge because they are very good at cooling. This is why they say not to idle them. Low cylinder temps=poor combustion.

I havent ran a single ounce of additive this winter and I havnt gelled once. I fill up at the newest and most turned over station in town with winterized diesel.

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It isn't so much as diesels are good at cooling, but at an idle there is just enough fuel injected to keep it running resulting in very little cylinder heat. Once it warms up there is enough residual heat that idling takes a lot longer to drop water temp.

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Most diesel will never move the temp gauge because they are very good at cooling. This is why they say not to idle them. Low cylinder temps=poor combustion.

I havent ran a single ounce of additive this winter and I havnt gelled once. I fill up at the newest and most turned over station in town with winterized diesel.

 

You know the first winter after I bought my truck we had a exceptional winter with a pretty good cold snap than saw actual temps down to -22 degrees.. I never gave any thought to adding anything to the fuel, and although I did keep it plugged in I never noticed a single issue other than the steering wheel was so damn cold it made my fingers hurt.

 

I have been running the howes this year because I now have remote filters under the truck, and some of the stories I have heard about (cold filter plug) made me feel like I needed some insurance. 

 

The more I read about this the more I think that some people in certain parts of the country are just getting really crappy fuel..?

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It isn't so much as diesels are good at cooling, but at an idle there is just enough fuel injected to keep it running resulting in very little cylinder heat. Once it warms up there is enough residual heat that idling takes a lot longer to drop water temp.

 

Correct, it's not the cooling abilities of the engine.

 

It's the extra mass to heat/keep warm, and the additional efficiency creating a smaller burn with higher compression that keep cylinder heat down.

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