To make calculations easy say diesel is 3.00 per gallon. What is the dollar amount to idle the 5.9 per hour? I was previously thinking somewhere like 40 dollars per 8 hours but it may be less. Has anyone actually calculated or at least have looked at how much fuel was used over a certain period of time?

 

Good question. I don't idle a lot. But I can do a test this weekend.

Since I already have some diesel in a portable container, I can top off my truck tonight and then do a test.

I probably won't do the test for more than 15 minutes though.

I am running Smarty Jr on level 1 (Economy), so that will have to be factored in.

I'll update this post sometime Sat evening.

 

That would be great, thamks

 

Well it will not be anywhere near $40 in 8 hours. Running down the road for 8 hours at 60mph and getting around 20mpg it only uses 24 gallons = $72 at $3.00 a gallon.

I would guess it would be closer to 2 or 3 gallons, 1/10 of what it would use to drive it for that amount of time.

 

I am anxious to see the results of that test - I have read on here and elsewhere anywhere between .3 gal/hour - 1.5 gal/hour while idleing. I can't imagine being much more than or even up to 1gal/hour, but who knows. Even at that rate - 8 hours would be 8 gallons used, at $3.00 per gallon is only $24.... at 1.5 gal/hr it is 12 gallons used, which would be $36, closer to the original posters thoughts....

 

This may seem like a silly question but how much more would it take if the engine were cold during the winter? 10-15% more?

 

These will be the parameters of my test.

Smarty Jr. on Level 1:
I'll double check the Outside Air Temp as indicated by the overhead reading
I will buy my diesel at the Local HyVee Convenience store
Drive 11 miles to home, top off tank (I have approx 5 gallons of diesel in my garage).
Set idle using the cruise at the lowest setting (I think it is 1100rpm)
I will not put in any additional additive (2 cycle oil and PS White) until after the test.

Game on in about 2 1/2 hours.

I'll update later tonight or early tomorrow.

Note: After I top off tank when I get home, I will pour some diesel in some empty quart containers and see much will be used to top off.

Note II: Then Smarty Jr will be going up to level 2 for a different type of test.

 

This may be a dumb question, but why do you guys let your truck idle for extended periods anyways?

 

some of us sleep in our trucks while on the road.i've idled for 12 hours at 1100 rpms and burned about 1/8 tank

 

Good start to your test- I'd recommend to get as accurate a measurement as possible, when you think the fuel tank is full, shake the bed side to side to slosh the fuel around, to eliminate air voids in the tank. this is crucial- there is going to be such a small amount of fuel used, the margin of error will be very small. i would be very surprised if you burn more than 1 quart an hour at idle, less than 1000 rpm. also- to start out on a level playing field, make sure your motor is at full temp- 190 degrees. you burn a lot more when that 1000 lbs. of steel is cold. speaking of a level playing field- make sure you are on one- not on a hill or incline

 

I leave my truck idleing a lot on the job site usually doing paperwork while waiting for subs or inspectors to show up. In the hot as heck summer I let it idle with the ac cranking for when I get back in.

 

I had to idle for 26 hrs in -24-28C and used about 3/8ths of a tank. Not calculated accuracy, but a benchmark to consider.

Cya

 

To the best of my calculations they will burn +- 1 quart/ liter per hour.

 

Excellent question. Just in case someone here isn't already aware, extended idling is probably the biggest killer of the 3rd gen injectors. Check your operator's manual.

 

Test results are in:

Engine temp close to 175-180 degrees. I took a picture of the gauge.
Outside Air Temp 27F
Topped off tank and then filled up to the fuel tank opening vent line (whatever the small hole is going toward front of truck).
I had to do the test today because even after I filled up last night, it still took all I had in my 5 gallon fuel can/container and that didn't bring it all the way full. So today, I took both of my diesel containers and filled them up as well as topping off the truck again.

So, the tank was full with fresh diesel, Most from HyVee last night, then Kum&Go today. Kum&Go it is 2% soy diesel.

My test measurements consisted of 10oz fruit juice containers (what I use for Power Service). I prefer the Orange Juice ones for the vitamin C(ummins).

Anyway I made a mark on the fruit juice container with a black Sharpie permanent marker. I did this on a clean container and matched it to the one that I used to top off the tank.

Then I took the clean one inside and poured water in it up to the mark.
Approx 8.5 ounces to the mark I made. It took almost 3 of those to top off the tank.

So, extrapolating all that information, brings me to the conclusion that approx. 23-25 ounces is consumed per 15 minutes at 1100 rpm idle.

Note: instead of Smarty Jr on level 1, I used the level 2 (Towing).
Since the towing is in between the HP settings of 1 and 3 we can guestimate the other two levels.

24oz * 4 (15 minutes) = 96oz or 3 qts/hour

The cost of the fuel for this test equates to $3.35/128*24 = 62.8 cents.

Enjoy.