Cold Weather Idle Strategy - Diesel Forum

CMB430 · 06-24-2008, 04:01 PM

Hello,

Is it possible to have the cold weather idle strategy removed from the computer? I think that when the next MN winter rolls around, which is closer that most want to admit, I could save quite a few dollars in diesel if it idled at 600 RPM instead of running up to 1150 RPM every morning for 6 months. Believe me when I tell you it does not make it warm up any faster. Plus, I have the snow plow package, so the damn fan runs hard, as if it is ready to overheat. I wanted to get your opinion before I make plans to take it into the dealer / start searching the internet.

Note: I know in winter this was discussed, but I do not remember seeing my question. Thanks!

rlchv70 · 06-25-2008, 07:02 AM

The answer is no. But why would you want to? Why do you think it doesn't warm up faster? The higher idle speed when cold is there for other reasons. Basically, when cold, the engine would run crappy at a 600rpm idle.

FYI - you don't need to let the engine warm up before you drive it. It will actually warm up faster if you drive it.

If you want it to warm up faster, use the block heater.

CMB430 · 06-25-2008, 07:15 AM

rlchv70 - Thanks for your response. I will let it rest at "No". However, I assume you do not live in a really cold climate. The block heater was used all winter long. I have to drive 60 mph for 12 miles before my truck starts to get warm. At 22-23 miles, it is at operating temperature. This is with a winter cover. You could let a 6.4 sit and idle for 6 hours, and it will not get hot when it is below zero outside.

But, again, thanks for your input.

timid1 · 06-25-2008, 07:29 AM

Quote:

Originally Posted by CMB430

rlchv70 - Thanks for your response. I will let it rest at "No". However, I assume you do not live in a really cold climate. The block heater was used all winter long. I have to drive 60 mph for 12 miles before my truck starts to get warm. At 22-23 miles, it is at operating temperature. This is with a winter cover. You could let a 6.4 sit and idle for 6 hours, and it will not get hot when it is below zero outside.

But, again, thanks for your input.

Why do you **have** to drive 60 mph for 12 miles before your truck gets warm? What does it matter that your truck is up to operational temperatures?

I live in California, so I don't have to deal with extreme temperatures.... just curious.

CMB430 · 06-25-2008, 11:26 AM

That is how long it takes to get warm. The average winter morning in MN is below 5 degrees. At 5 am, that is really cold. In order to get heat, the truck must be warm. The plug does not make the coolant warm enough to make a difference...only makes it easier on the engine. I drive 28 miles one way to work. Perhaps that is why I had so many regens in the winter. Like you said, letting it idle will not make it warm, but it does let oil get to where it needs to be. So in an effort to save some cash, I want to stop the high idle strategy.

Dr.Evil · 06-25-2008, 01:51 PM

[quote=timid1;1589267]Why do you **have** to drive 60 mph for 12 miles before your truck gets warm? What does it matter that your truck is up to operational temperatures?

QUOTE]

95+% of engine wear takes place in the first few minutes of running while the engine is getting up to temp. Raw fuel and water vapor from incomplete combustion sneeks past the rings into the crankcase & engine oil causing oil dilution and sludge. If You notice in Your Owner's manual when running short distances in cold temps Your supposed to perform oil changes more frequently because of this. Plus Your MPG is much less.

I live in southern WI and when I used to run My OBS truck to work 60 miles each way daily even with the winter front totally sealed up it also took 15-20 miles to get up to normal operating temps. And that was with the truck plugged in at least 3 hours each morning in an insulated garage that seldom got below 35 degrees. I would lose about 1-1/2 to 2 MPG each winter and could tell to the week when My normal fuel station started getting blended fuel for winter.

Also in cold temps tires flex less and actually pull harder, oils & greases in axles & bearings, & gearboxes pull harder because they're thicker. Even with synthetic oils & greases. It's also a lot easier on these engines to warm them up easily and cool them off slowly....makes them last a LOT longer.

CMB430 · 06-25-2008, 07:07 PM

That is why I like it to idle for a few minutes (3-7 min) before pulling out. I also, even now when it is 90 degrees, let it idle for at least 1 min before turning it off. That is with no load. I average 16.8 mpg when it is above 50 deg, but when it is below I get closer to 14.5 mpg. So I assume you understand how idling high when it is Jan weather does nothing for mileage. There must be a fix for it...and I will find it.

rlchv70 · 06-26-2008, 06:15 AM

Quote:

Originally Posted by CMB430

That is why I like it to idle for a few minutes (3-7 min) before pulling out. I also, even now when it is 90 degrees, let it idle for at least 1 min before turning it off. That is with no load. I average 16.8 mpg when it is above 50 deg, but when it is below I get closer to 14.5 mpg. So I assume you understand how idling high when it is Jan weather does nothing for mileage. There must be a fix for it...and I will find it.

Idling the engine does not do much to warm up the engine. If anything, it exacerbates the types of conditions that Dr. Evil was talking about above.

The fix is not to let it idle for so long.

Also, you don't need to let it idle for extended periods before shutting off. The only time that i would recommend this is when you have been towing a heavy load at high speeds.

GrampyJim · 06-26-2008, 09:45 PM

Quote:

Originally Posted by CMB430

That is how long it takes to get warm. The average winter morning in MN is below 5 degrees. .

This is cute... you don't know what cold is either.... 5 degrees F is a warm January day.

Now.. the nature of the beast.... without a throttle plate, the cylinders on a diesel flow a LOT of cold air on a cold day. This cold air drags heat out of the engine.... and leaves us with <GASP> "wet stacking"... engine oil becomes diluted with fuel, cylinder walls wash down... exhaust after treatments get gummed up.

Your engine is trying to do everything it can to warm up... and you are trying to stop it from doing that.

FWIW... I would love to have the torque of a diesel.... My driving situation makes one a very poor choice....

BIGBEN2004 · 06-27-2008, 10:26 PM

The best thing would be a gas engine especially since you drive such a short distance to work. Not trying to start a argument just a opinion from a man on the sideline. A gas engine would warm up faster and wouldn't matter as much if it runs a short time and shuts down quickly.

CMB430 · 06-27-2008, 10:31 PM

I have had several gas trucks. I bought a diesel because my last truck, a 2006 2500HD would not tow my trailer well. It had a 6.0 with the 5spd. The 6.4 has the torque I need. Thanks for the advice.

checkthisout · 08-20-2008, 02:14 AM

Quote:

Originally Posted by CMB430

rlchv70 - Thanks for your response. I will let it rest at "No". However, I assume you do not live in a really cold climate. The block heater was used all winter long. I have to drive 60 mph for 12 miles before my truck starts to get warm. At 22-23 miles, it is at operating temperature. This is with a winter cover. You could let a 6.4 sit and idle for 6 hours, and it will not get hot when it is below zero outside.

But, again, thanks for your input.

Ok so you have figured that letting it idle does not make it warm up faster so you want to kill the fast idle feature in order to save fuel when you are idling to let it warm up?

OMCUSNR · 08-20-2008, 09:49 AM

From the posts here, I'd say your economy loss is in line with the switch to winterized fuel. #1 has less BTU's than #2 and it's not uncommon to see a loss in economy because of it.

"If it were me"...I'd look into a good bypass filter system, Schaeffer's 9000 5W40 Syn and look at running that all year. I'd start the truck, let it settle down a minute or so , and then start driving moderately. I know the syn is more expensive, but with a good bypass filter, extended OCI's are possible (make sure you use oil analysis to tell you when - pull one every 5k).

It usually takes me about 5 mins to get to the interstate, and by then I can get it up to speed easily. Since you have a manual, it's easy to select your shift points, which I'd keep at about 2k until the temp gauge moves.

OMC

rlchv70 · 08-20-2008, 10:08 AM

5w40 will probably get you worse fuel economy in the winter than 10w30. Once the oil is warm, it is the "40" part that dominates.

CMB430 · 08-20-2008, 10:08 PM

Wow! My old post is revived. I used to run 5W 40 in it when I first got it...Amsoil. But the cost of an oil change was too much. I now run the Motorcraft 15W 40, and will run it again this winter. I spoke to a bunch of truck drivers, and they said it will not hurt anything. Like it was pointed out above, I do keep my shift points down, even now. That is why I can get 17 mpg. But I do not want another gas truck, and my logic told me that the high idle is no good. I will leave it alone, and not let it idle so long in the mornings.

Thanks for all of your input.