Question: 5th Gen Fuel Consumption at Idle

[JB.]

Does anyone have any idea on idle fuel consumption? This would be under normal loads like heater, interior lights, etc. There is a rule of thumb of around 1/3 of a gallon per hour. Has anyone tested this out?

It appears to be about .4 gallons per hour for the 4th gen V8 so I'll bet 1/3 gallon per hour is really close.

http://www.toyota-4runner.org/4th-gen-t4rs/24717-how-long-can-you-idle-tank-gas.html#post212014

 

[JayceeP]

I feel like the consumption would be higher... At least this time of year and only based on the really high consumption I have seen over the last 2 months. I am consuming 30% more fuel vs my summer numbers and at least 10% more than I did last winter. Not sure why but these last few tanks are the worst I've seen in my 2 years of ownership.

I have spent a little more time in the drive thru and the idling has really hurt my fuel economy. For me I am also using the heated wipers at every start up so the anti-freeze doesn't ice them up, ass warmer on full blast for the first 10 mins and heater at 22C.

Edit: saw this post and and that seems more comparable for me: 2.2L/hr is almost 0.6 gal/hr though... big difference. Oh well.

While idling after an hour long drive on a 12*C day I saw as low as 1.3L/h with no accessories on and as high as 2.2L/h with everything switched on. Seems consistent with the sub half gallon estimates.

 

[KVA]

Yeah that will be a screenshot in somebody's signature line..

Was totally thinking this...lol

 

[Kotrin]

The only impact of a hot versus a cold start would be in the initial first start for around five minutes. The other 60 hours would be the same lol.

The reason for asking is just that: If you were camping, wrecked, blizzard, hurricane'd or other such disaster how long could your vehicle idle on a tank of gas?

Example:
We had a storm roll through here a few weeks ago and we (and about 5,000 others) were without power for almost three days in below freezing conditions. I have a generator of course and secondary heat sources but many people apparently don't think like I do and many resorted to their vehicles for heat and power, especially that first night.

Example:
Last year during a winter storm several thousand people got stranded on a section of local interstate for 12 hours.

That is my premise for the question. If my estimate of 1/3 GPH fuel burn is correct then you could go 60 hours continuously (with reserve) idling without refueling.

I've idled my Tacoma for several hours and got around 1/3 to closer to 1/2 as I had the heater on full blast due to my son being in the car.

What I would like to to ask is what sort of harm would this cause your engine. Personally I don't see any but over long time I could see it possible excessive build up that a few 'fast drives' could fix =)

 

[1engineer]

It appears to be about .4 gallons per hour for the 4th gen V8 so I'll bet 1/3 gallon per hour is really close.

http://www.toyota-4runner.org/4th-gen-t4rs/24717-how-long-can-you-idle-tank-gas.html#post212014

You win the oldest post award for this week! Yay! Seriously, thanks for that as it is good stuff as usual.

 

[NoDak]

lol and I imagine anyone up in the northern tiers, Canada or Alaska can tell you, idling for that long of a period will cause bigger issues on gasoline engines (not so much on diesels).

older cars tend to catch on fire when sitting for long periods running at idle.

newer cars I haven't seen too much of this happening, but with no air going over the plastics parts under the hood, they tend to melt and catch fire and it just spreads.

I have seen a few cars over the years where they have left the car idle for 1-2 hours and catch on fire and one lucky person in the BK lot, it took only 20 minutes to catch on fire (no idea the story before he parked in BK since I was in the Wendy's dining area next door).

and it doesn't matter if its -20F or 20F, I've seen it happen at both extremes.

 

[JeremyB]

With it in Drive, 10 second average of 3.87 g/sec MAF. Sat with it in Park for 10 seconds before shutting it off, but the MAF rate was still decreasing at 10s. Was at 4 g/sec then. Will have to try again.

With E10 (in drive) that comes out to ~0.36 gal/hr if I did the math right.

Edit 1:
A/F = 14.13
rho = 0.0265 lb/in^2 (735 kg/m^3)
40 degree ambient temp

2014 4Runner Idle.xlsx
In driveway, stationary after a trip

0-12.08s - In park
12.08s - Shifted to drive (while brake holds the vehicle still)
15.26s - Stabilized in drive
23.6s - End logging

Edit2: While in park, average MAF for 11 seconds was 3.74 g/sec. Which is ~0.35 gal/hr of E10 fuel.

 

[Jhalko]

Are we talking "winter" gas or "summer" gas and do you have 285's installed?

I thought I remember my scan gauge reading something like .3x gallon an hour while I was idling, but I might be crazy and just delusional from the carbon monoxide.