Fuel Consumption on Idle and on key starts

**bughaw787** · May 13th, 2008 03:46 PM

Does anyone know how to compute fuel consumption when the engine is on idle given the Engine displacement and RPM.

Tried searching the net and the most i can get is:
Typical Engine Idle Fuel Consumption:

500-700RPM >>>> Half a Gallon/Hour (1.8918 liters/Hour)
900-1200RPM >>>> 0.75 GPH (2.8377 LPH)

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FC on a 2-second keystart is about 0.0024/Gallon (0.0091/liter)

**niky** · May 13th, 2008 05:25 PM

You'll need an O2 sensor to back-calculate... some cars run slightly rich or slightly lean at idle... so you can't always tell from displacement and rpms.

The only really accurate way is to actually test it with a flow-meter attached to your fuel line.

**feeter** · May 13th, 2008 09:55 PM

Just want to share this...
Our Starex idled last night, with aircon for at least 5 hours. The fuel marker before is just slightly lower than the halfway marking, then when I checked after the 5-hour idling, the marker drops to near the baseline. Horrible isn't it? But when I drove it again, the marker rises up again to one- fourth marker and the expected FC for the entire trip was achieved accordingly.

**v6dreamer** · May 13th, 2008 10:43 PM

Originally Posted by feeter

Just want to share this...
Our Starex idled last night, with aircon for at least 5 hours. The fuel marker before is just slightly lower than the halfway marking, then when I checked after the 5-hour idling, the marker drops to near the baseline. Horrible isn't it? But when I drove it again, the marker rises up again to one- fourth marker and the expected FC for the entire trip was achieved accordingly.

Why would you do that? 5 hours of idling w/ a/c on! Of course its horrible not to mention how many liter of gas you've burn for nothing, I understand if this is a long driving, but sitting that car idling for so many hours... I dont get it.

**bughaw787** · May 14th, 2008 04:03 PM

Originally Posted by niky

You'll need an O2 sensor to back-calculate... some cars run slightly rich or slightly lean at idle... so you can't always tell from displacement and rpms.

The only really accurate way is to actually test it with a flow-meter attached to your fuel line.

*niky

Was just thinking (especially if you have a new ride), the car would basically be running on a standard mix on idle. Doesnt have to be exact - an estimate would be fine so that we can have a general idea on FC.

**mazingerZ** · May 14th, 2008 04:21 PM

Originally Posted by v6dreamer

Why would you do that? 5 hours of idling w/ a/c on! Of course its horrible not to mention how many liter of gas you've burn for nothing, I understand if this is a long driving, but sitting that car idling for so many hours... I dont get it.

Baka brownout at nanood na lang sila ng DVD sa starex sir v6.

**v6dreamer** · May 15th, 2008 01:39 AM

Originally Posted by mazingerZ

Baka brownout at nanood na lang sila ng DVD sa starex sir v6.

Oo nga noh! Bakit hindi ko pala naisip yon.

**aga_cruz** · May 15th, 2008 10:46 AM

mga peeps saken mga 2 hours lang naka idle yung mb100 ko bakit kaya bumaba din ang fuel gauge???

pero nung itinakbo ko tumaas naman kahit papaano?

**coiter** · May 15th, 2008 11:39 AM

actually naiisip ko rin yan (FC on idle) just to guage kung gaano kalaki effect ng pagaantay sa sasakyan or kung trapik.

i guess the only way is the usual way kung saan magpa full tank ka, idle ka for kahit mga 1 hour (para medyo considerable ang bawas), then pa full tank uli. kung ano nadagdag sa 2nd full tank, yun ang liters/hour mo. divide mo by 60 para maging per minute para mas accurate.

pag alam mo na yan, most likely di ka na uli tatambay sa sasakyan mong naka on or lalo kang magngingitngit sa traffic kasi bilang na ang gas mo kada minutong di ka gumagalaw! hehehe

**bughaw787** · May 15th, 2008 11:44 AM

Originally Posted by coiter

actually naiisip ko rin yan (FC on idle) just to guage kung gaano kalaki effect ng pagaantay sa sasakyan or kung trapik.

i guess the only way is the usual way kung saan magpa full tank ka, idle ka for kahit mga 1 hour (para medyo considerable ang bawas), then pa full tank uli. kung ano nadagdag sa 2nd full tank, yun ang liters/hour mo. divide mo by 60 para maging per minute para mas accurate.

pag alam mo na yan, most likely di ka na uli tatambay sa sasakyan mong naka on or lalo kang magngingitngit sa traffic kasi bilang na ang gas mo kada minutong di ka gumagalaw! hehehe

kaya lng sayang sa gas - tambay ka pa sa gasolinahan - holdap/carnap naman katapat natin dyan.