Gas burned per minute spent idling figures?
 

Googled it and only found anecdotal data from 1/2 to 1 gallon per hour idling.
Do you know of more accurately tested figures for different cars?

I believe consumers should push for car magazines and gov't to test and publish such results.

If you have instant MPG reading capability, then coast in neutral with engine idling until your reading drops below max gauge capability.

In my 2002 Insight the speed was 16 MPH when the instant MPG gauge dropped below the max reading of 150 MPG. I divided 16 by 150 to come out with idle consumption of .11 GPH.

.5 GPH for most V8s
.33 GPH for most V6s
.25 GPH for most 4 cyls.

These are average numbers but can vary considerable depending on engine displacement and idle speed. Adding loads like AC can increase it substantially.

I used to tell people that my Insight would go 40 MPH on the same fuel a V8 used to just idle itself (.5 GPH and 80 MPG at a steady 40 MPH (CVT not manual)).

regards
Mech

According to my gauge, my Toyota Celica GTS with the 2ZZ engine uses between 0.21 and 0.26 Gallons Per Hour idling when warm, depending on the number of electrical loads I have on or off. (Mainly the difference is lights at night.) Fuel consumption idling cold is significantly higher.

My 2.0L Hyundai Elantra is ~0.34 GPH on a cold engine cold winter day, and ~0.25 GPH after warmed up.

I thought...
 

That I could pull up some good solid research from here. Alternative Fuels Data Center: Case Studies
But the best I could do was B/S for dummies I believe would be my best description. None of the test results or base line graphs Id expected just stupid stuff like starting a car takes energy lol. I am exaggerating somewhat but look for yourselves. Our GOV.
heres a widgets page mabe some nugget hiden here? Alternative Fuels Data Center: Widgets
I am thinking I may find better info on the CARB site though.
I am sure the fed is just suckling off of Ca. ground breaking discoveries and plans now.

Carb also has naught for passenger vehicles but thier Index is awesome tons of stuff for bored eco minded surfer to explore. http://www.arb.ca.gov/html/all.htm.

My car (2.0L Neon) = up to 0.50 GPH idle when cold, as low as 0.28GPH warmed up. Probably 0.32 GPH average after warmed up, though.
Wife's car (1.5L Scion) = ? cold, as low as 0.14 GPH warmed up.

W/o scangauge or similar device, it's hard to say what you'll get.

.42 GPH stock and now I got it down to .39 GPH still not very good for a 2.0L

This is one part in my application I have not been able to improve on very much. Low compression turbo engines use a lot of fuel at idle :(

One thing I noticed... When I cleaned my IAC (Idle Air Control) unit, I kind of "broke" it... after I reassembled it and forced it back into position, startups went 1.5K RPM down to ~700, where prior was up to 2.5K and down to around 1.3K until warmed up. Was holding .5GPH idle, now doing about .43 w/ the lower rpm.

2013 GMC Seirra 5.3 with no acc on in park. I recently measured at 1.919 LPH after a thorough warmup from a stone cold start. The fuel burned to get the engine warmed up is mind bogling at a total of 3 Liters in 18 minutes. Where a hot engine would only burn 0.58 liters in the same amount of time.

1.919l = .51 gal U.S.

3l = .79 g

.58l = .15 g, or

.45 to .5 gallon/hour idling when warm
.8 gallon during 20 minute warm-up from cold

This is useful to me because there is a sea of V8s autostarted and idled around here for 6 months out of the year. Now I can attach some numbers to it all- probably a gallon for each autostart event because it is plain to see most last longer than 20 minutes; and 1/2 gallon per hour from then on, like at the local parking lots. :mad:

My metro idles when warm anywhere between .08 to .11 per hour.

1l to 5.3l;
.08-.11 x 5.3 = .42 to .58;

Roughly comparable liter-to-liter with the big V8s.

I don't turn off my Versa's engine unless I pull up to a light that I know from experience has a frustratingly long wait. Or there's a train. I figure even at 1/2 gallon per hour, any savings I get will be negated by the increased workload on the starter and the engine wear on startup. I can buy a lot of fuel for what Nissan would charge me to replace my starter.

I read a book a while back (How to make your car last forever) that explained how every time an engine is started, before the oil pressure builds up to do it's normal job, the metal-to-metal wear on the main bearings and the other initially non-lubricated parts of the motor like the camshaft and timing gear is the same as if you drove 500 miles.

Haven't measured the other two vehicles in my stable, but the Karen-mobile consumes anywhere from .48 to .56 gph at warm idle. From a cold start in the 20 F - 30 F range, cold idle goes from about 1.1 gph and steadily drops. This is with an MPGuino.

Gotta get MPGuinos installed in my other two vehicles!

I had previously measured the Insight MT at 150mpg at 20 mph. This is the point where the instant fuel consumption indicator starts to drop, due to the reduced speed when performing a coast down test with the engine on.

If I did the math correctly, this comes out to 1 gallon every 7.5 hours, or 0.13 GPH.

Jim.

I will have more information tomorrow hopefully, but it seems that my vibe hot idles at 0.53L per Hour. I did find out with my latest expermental software Dashcommand that I can coast at highway speeds at over 300MPG, I am sure that it is close enough to infinity not to justify engine off coasting.

I am liking Dashcommand over torque so far. I am hoping that the logged data is compatible with my laptop software scanxl

I am doing a cold soak start and idle warmup to full operating temp. Then I can compare it to my blockheater starts next week.

I got a harbor freight generator that is rated at 800 watts, runs 5.5 hours on a gallon of fuel. Wow, either its pretty efficient or just a very small displacement?

Idle warmup done today from cold soak for my Vibe.

It was -1 degree C and the coolant was at -6 when I started. It took over 20 minutes to warmup to 180 degree Fbut the engine did eventually flatline at 185 degree F. It looks like it only takes 20 seconds to get into closed loop mode, which is great. I burned just over .3 L during the test and my car hot idles at 0.526 LPH or 0.139 GPH.

Have you run it loaded?
 

Probably small displacement because it's not very efficient. The energy content of a gallon of gasoline is 36.6 kWh, and 800 watts for 5.5 hrs is 4.4 kWh, so the efficiency is only about 12%. And i doubt it will run at 800 watts continuously so efficiency will be even less.

Fully warmed idle for my xA is 0.16-0.17GPH. I try and catch the cold idle soon.

It was a cold and dark night... furnace quit, had to drive to the next town for parts. Furnace man was nice enough to get outta bed and meet me at his shop so I said I'll be there at xxxx time. Get in the T-Racer, get maybe two blocks down the street, stupid cop pulls me over, "Why are you going so slow?" DERP DERP DERP I will continue to warm up gently at first while driving rather than idle, thank you very much.

IMHO,any book that claims even a cold start is equivalent to 500 miles driving would have to be suspect, especially considering the abilities of modern lubricants.

Shutting off the engine for a few minutes at the lights isn't enough time for ALL the oil to drain back from wearing parts and a warmed up engine (and oil) regains full circulation very quickly on restart.

The only consideration I see is, have you saved enough fuel through not idling for those few minutes to more than cover the extra load on the charging system that the starter used.
In most cases, I think it's worth switching off for even a short stop.

I'm on my third Nissan/Datsun (all autos). The first was 25 years old when I sold it, still with the original starter and the second ran 20 years on the original. I don't think you have much to worry about in that regard.

Updated: Helga idles between 0.12 and 0.14gph

That's one Ill have to remember... though it sounds like you stopped telling people that?

Checked my SG and it looks like 0.5 gph at 40mph for Helga as well.

Do you shift to N to switch off, I do - I'm still learning autos and their evil ways...

If you're talking about turning off at traffic lights, I usually coast up to the lights in neutral anyway, so the answer is yes.

If you're talking about a sudden stop with no coasting, I don't think it makes any difference.

Yep thats what I meant, as for the latter I try and avoid by leaving a gap - also helps if people want / need to pass so they have somewhere to tuck in...

...not that they appreciate this of course. :turtle:

As for the OP - 0.23 GPH at IDLE in N, 0.47 in D. 2.7 TDI, Slushbox.

??? My xB (same engine) idles @ .11-.15 gph.

Well, that is here in New England in the winter, and so I probably had the fan blowing and maybe the rear defroster on. I also have the cold air intake from Toyota on my car.

I have tried to see what a cold start is, and I think it is ~0.51-0.55GPH until the temperature tops ~125-130F?

I'll add the figures for my 4.7L V8 Ram. Once warmed up, it idles at 490-510rpm and 0.45-0.50 gal/hr. My wife's 2.4L I-4 Avenger will idle at about 700rpm, at 0.34 gal/hr.
Ram has an MPGuino; Avenger has an OBDuino.

if 1 US Gal/hr = 3.78541178 liters / hour then my truck drinks 1.7-1.893 l/hr at idle. Wow. But, for a V8 it still seems pretty good.

@Frank Lee, I hear you on people idling vehicles in driveways. It's ridiculous. People here in OKC do it when it's 50*F outside. Really? Saw the same thing when I was in San Antonio.

Yea those things will do that, my 1ZZ-FE and 2ZZ-GE were both around 0.18GPH fully warmed up, zero accessory load, with much more displacement than your 1NZ-FE.

The high cold start makes sense since older engines tend to keep the revs really high on a cold start. I noticed newer cars will settle to 900-1200rpm quickly even if it's freezing cold, whereas older cars will target 1500-1900rpm. I'm guessing better combustion chamber design allows much more ignition timing retard on higher throttle opening leading to more efficient catalyst warm up.