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Posted

How much fuel does idling actually use? I was always under the impression that the amount was negligible, but while sitting parked in my truck the other day I noticed on my DIC that my average MPG dropped about 1/10th MPG for about every 30-40 seconds spent parked idling..

Posted

They don't burn much at idle, I would expect 1-2L per hour, or for you Americans, a half-gallon per hour at the most. My 15L Cat diesels only burn 1 metric gallon per hour at idle, which is 3 times the size of our pickup's engines. The DIC moves a lot because you are burning fuel without the truck in motion. 

Posted

It burns enough while idling that you are better off shutting it off and restarting than letting it idle for anything more than 10 seconds. Not since your old carbureted car has it been more fuel conscious to leave it idling.

  • Like 3
Posted
1 hour ago, mistermcgoo said:

How much fuel does idling actually use? I was always under the impression that the amount was negligible, but while sitting parked in my truck the other day I noticed on my DIC that my average MPG dropped about 1/10th MPG for about every 30-40 seconds spent parked idling..

 

Would this be dependent on how long it's been since the average was reset?  Meaning if you have 2,000 miles of highway driving since it was last  reset, your average likely won't drop at all even if idling for an extended period of time, but if you reset it earlier that day and only drove 20 miles then it will drop much quicker. 

Posted

My Gen IV motor burns about 1.3 GPH idling and 1.7 GPH idling right after a cold start.  She burns about 2 GPH while driving, this is the average after almost two years of record keeping.

  • Like 1
Posted (edited)
On 8/26/2019 at 8:44 AM, mistermcgoo said:

How much fuel does idling actually use? I was always under the impression that the amount was negligible, but while sitting parked in my truck the other day I noticed on my DIC that my average MPG dropped about 1/10th MPG for about every 30-40 seconds spent parked idling..

The DIC drops quickly because when idling it's getting 0 mpg; the DIC shows a distance-rate usage, not a time-rate usage.  This is why start-stop tech is becoming more and more prevalent to eek out every last mpg for the EPA.  As mentioned above, just shut if off.  Idling is HORRIBLE for an engine.

Edited by dukedkt442
  • Like 3
Posted

This is a trick question. To answer it one must know what temperature it is out side what is the engine coolant temp and what are the o2 reading. As all effect fuel demands.
I would rather the truck run then shut off.
But I say this because of all the other items that have to start back up. Electrical to mechanical to the fluids.

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Posted

My trucks were beast of burden. They would usually start in the morning and shut off at night. It’s damn hot in Texas. They would sit for hours running. Since fuel injection I never had a problem. It probably cost me a couple miles per gallon overall. But I was comfortable.


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Posted

Many variables are needed everything from elevation to ambient temp?  They sip probably 1.5-1.7gph under max conditions?  That sounds about right.............imo?

Posted

idling for 5 mins while waiting for someone or you idling for 3 hours for whatever reason? Big difference.

And if you have the need to idle, the reason will be more important such as you need AC on or heat on, in that case i wouldn't care about the fuel since your other needs are necessary at that time.

  • Like 2
Posted
On 8/26/2019 at 7:42 AM, swathdiver said:

My Gen IV motor burns about 1.3 GPH idling and 1.7 GPH idling right after a cold start.  She burns about 2 GPH while driving, this is the average after almost two years of record keeping.

This sounds about right. I was idling stuck on Highway 50 in Tahoe and it was burning through fuel at an alarming rate (considering how large the tank was, only having a half tank of fuel left, and knowing we would be there for several hours). 

 

In my V6 Lexus, it is probably closer to .5 gph (1/3rd the rate). We encountered a closed road with no turning back, idled the motor for 10 hours, and used a quarter tank of fuel or so. 

  • 1 year later...
Posted

Is there anything I can do to help with my fuel while ideling? I work traffic control and I'm burning fuel real fast. Never use to do it before.

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