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Old 07-18-2016, 03:41 PM
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Idling vs restarting an EcoDiesel

I'm sure many of us have pondered the tradeoffs between stopping/restarting our engines as opposed to just letting the diesel idle in the parking lot while we run some quick errands.

There must be an estimated duration where it would be better to shutdown/restart as opposed to idling. I'm sure that this duration is further extended for GDE tune users, due to their algorithm that reduces soot production. For the sake of discussion let's presume the cost of diesel consumption at idle is de minimis and we are concerned only with long-term engine health.

What rules of thumb do other people use?

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Old 07-18-2016, 05:54 PM
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Quote:
Originally Posted by Roadkill View Post
I'm sure many of us have pondered the tradeoffs between stopping/restarting our engines as opposed to just letting the diesel idle in the parking lot while we run some quick errands.

There must be an estimated duration where it would be better to shutdown/restart as opposed to idling. I'm sure that this duration is further extended for GDE tune users, due to their algorithm that reduces soot production. For the sake of discussion let's presume the cost of diesel consumption at idle is de minimis and we are concerned only with long-term engine health.

What rules of thumb do other people use?
Don't know if that Chrysler diesel supplement holds any weight, but I thought it said to avoid idling it for extended periods. Might be a consideration
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Old 07-18-2016, 06:42 PM
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Quote:
Originally Posted by Floridaman View Post
I thought it said to avoid idling it for extended periods.
Good point.
Engine Idling
Avoid prolonged idling, long periods of idling may be harmful to your engine because combustion chamber temperatures can drop so low that the fuel may not burn completely. Incomplete combustion allows carbon and varnish to form on piston rings, cylinder head valves, and injector nozzles. Also, the unburned fuel can enter the crankcase, diluting the oil and causing rapid wear to the engine.
...and then in the next breath they talk about when you *should* idle the engine for a while (heh).

I wonder if EGT is a reasonable proxy for combustion chamber temperature.

Presumably this low combustion chamber temp scenario isn't applicable to GDE tune users with high idle, when it's currently active—though this isn't the end-user reason for that optional feature.

I suppose if these EcoDiesels ever get a stop-start added with no salient mechanical changes then the debate about whether the engine should be stopped for quick errands will take a turn.
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Old 07-19-2016, 10:02 AM
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Re: Idling vs restarting an EcoDiesel

I can only offer antidotal information from the 189000 miles I put on my SuperDuty.
I never let it idle this isn't some huge Cat engine that needed to do so. Fuel consumption was 1 oz per minute or about a gallon an hour.
Never a starter issue doing this and never a problem.

I don't see any point in letting any diesel idle unless super cold where restart could be an issue. Cold stacking is very possible in cold climates doing this because the engine isn't under load...


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Old 07-19-2016, 02:23 PM
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Quote:
Originally Posted by fun2drive View Post
I can only offer antidotal information from the 189000 miles I put on my SuperDuty.
I never let it idle this isn't some huge Cat engine that needed to do so. Fuel consumption was 1 oz per minute or about a gallon an hour.
Never a starter issue doing this and never a problem.
Seems to be good advice.

Quote:
I don't see any point in letting any diesel idle unless super cold where restart could be an issue. Cold stacking is very possible in cold climates doing this because the engine isn't under load...
Definitely. Too bad the stock firmware doesn't have a high idle condition to prevent this... something the GDE tune offers an option.
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Old 07-19-2016, 04:55 PM
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Re: Idling vs restarting an EcoDiesel

I'll idle until oil temp drops to 208F and then turn it off. If the oil temp is already 208F or less, I'll turn it off when I expect to idle 10 seconds or more when safely parked or waiting at a drive through.

The 10 second rule is just some advice gleaned from a hypermiler forum. It was for gassers, but I imagine this small displacement diesel to be similar.

Safety > comfort > economy. If it's unsafe or too hot/cold to be comfortable with the engine turned off, leave it running.
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Old 07-25-2016, 08:56 AM
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Re: Idling vs restarting an EcoDiesel

Is that a real oil temp? On the Cummins it's calculated, not real, no sensor. Event the oil pressure gauge on the older Cummins isn't real, just a glorified idiot light. I don't trust OEM gauges not one little bit.
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Old 07-25-2016, 06:05 PM
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Re: Idling vs restarting an EcoDiesel

Quote:
Originally Posted by Tinman2 View Post
Is that a real oil temp? On the Cummins it's calculated, not real, no sensor. Event the oil pressure gauge on the older Cummins isn't real, just a glorified idiot light. I don't trust OEM gauges not one little bit.
I suppose it depends on how you define "real". As I understand it, the temperature sensor is on the outlet of the oil cooler just before the oil goes back to circulation. So, it is "real", but I don't know that I'd consider it "true" since the oil temperature would be higher almost everywhere else in the system, especially near the turbo.

Really, I don't care if it's real. It could read 0 or 1, as long as 0 means safe to turn off and 1 means idle until 0.

It serves the purpose and seems to move in a realistic fashion. When it's super hot outside and I've been driving hard, it takes a long time to cool down, as you'd expect, and conversely for the opposite conditions, as you'd expect.
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Old 07-30-2016, 01:31 PM
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Re: Idling vs restarting an EcoDiesel

Quote:
Originally Posted by Roadkill View Post
I'm sure many of us have pondered the tradeoffs between stopping/restarting our engines as opposed to just letting the diesel idle in the parking lot while we run some quick errands.

There must be an estimated duration where it would be better to shutdown/restart as opposed to idling. I'm sure that this duration is further extended for GDE tune users, due to their algorithm that reduces soot production. For the sake of discussion let's presume the cost of diesel consumption at idle is de minimis and we are concerned only with long-term engine health.

What rules of thumb do other people use?
Once your exhaust temp drops below 350 degrees shut it down. Your only reason to idle is to cool the turbo down to prevent oil coking in the turbo.
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Old 08-01-2016, 03:22 PM
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Re: Idling vs restarting an EcoDiesel

Unless it's really hot outside and, I'll turn off the ignition when I know I will be waiting more than a couple of minutes like when I'm waiting for a mile-long train to go by at 20 MPH.

Two minutes of no AC in the summer sun is worse than 2 minutes of no heat at -20F when you are wearing a winter coat and warm socks.
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Old 08-10-2016, 05:47 PM
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Re: Idling vs restarting an EcoDiesel

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Originally Posted by Hammerhead View Post
Unless it's really hot outside and, I'll turn off the ignition when I know I will be waiting more than a couple of minutes like when I'm waiting for a mile-long train to go by at 20 MPH.

Two minutes of no AC in the summer sun is worse than 2 minutes of no heat at -20F when you are wearing a winter coat and warm socks.
The way I look at it, any Vehicle I own better be able to take care of me regardless of any external conditions...whether it is 95 Deg out or -15 deg out. If I want or need it to Idle for 30 min waiting to pick some one up etc, then I surely hope it can be able to do that with no adverse effects on the unit. That's all part of what product testing and engineering is for....
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Old 08-10-2016, 06:58 PM
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Re: Idling vs restarting an EcoDiesel

Quote:
Originally Posted by Stbentoak View Post
The way I look at it, any Vehicle I own better be able to take care of me regardless of any external conditions...whether it is 95 Deg out or -15 deg out. If I want or need it to Idle for 30 min waiting to pick some one up etc, then I surely hope it can be able to do that with no adverse effects on the unit. That's all part of what product testing and engineering is for....
If you sell or trade every few years, it won't matter. If your a long term owner you'll pay for it later on.
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