Engine/Transmission (1998.5 - 2002) Fuel Consumption@Idle

[RBSOB]

Anyone know what a stock ISB fuel consumption rate {GPH} should be? I'm just trying to figure how much increased cold weather idling effects winter mileage versus the less efficient "winter blend" fuel. Thanks for any input, Jim G.

 

[ToolManTimTaylor]

1. Hey Neighbor! Haven't seen ya arround a while !



2. I remember reading idle consumption is very little as the fuel is pre meetered by the ecm juust to keep the motor running at a set rpm. Ugh I wish I remember the thread. Try a search on " Fuel at* idle "



*Edit* I tried the search an the site is having an issue so try it l8tr.



HTH

TMTT

 

[Bigsaint]

I know I saw it somewhere, can't remember if it was here or Fritz's site ??? Regardless, it has a impact that is quite obvious for me as I have to idle while at the bus stop each morning for about 15 minutes and usually idle at work before I leave for about 10 minutes. My mileage drops about 3 MPG with the combo of the winter fuel and the idle time ( always with the ebrake on).



Scott W.

 

[RBSOB]

Hey TMTT and Bigsaint, still haven't got a figure for GPH @ idle, but into my 3rd winter now with the '01 and mpg is about -3 compared to warm weather. Sounds like we're in the same ballpark. I had switched to a 5-40 synthetic at last O. C. starts quicker in the cold but no noticable increase in mpg. Thanks, Jim G.

 

[Bigsaint]

Jim, I just posted a new thread. Hopefully someone with either the INSITE software or a ROAD RELAY will respond.



https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=63402





Scott W.

 

[RBSOB]

Thanks Bigsaint

Thanks for the follow up on this topic, Scott. I thought for sure this would be an easy question, with a published figure for GPH @ idle, available somewhere. Any how... it seems we are both idling away 2-5 gallons\week in winter temps. and this will have a very noticable impact on mileage\gallon. Have a Great New Year, Jim G.

 

[Bigsaint]

Yikes Jim, you posted for me . How'd ya do that ????



Hopefully we will get a response from a pc user . I searched high and low, couldn't find where I read the data from ???



Scott W.

 

[EricBu12]

a big n-14 Cummins will Idle at . 7 GPH



So a 5. 9 might idle at say . 3GPH? give or take... .

 

[RobbyRam]

I just checked the 'gallons per hour' at idle with my 'Cummins Quick Check II' Scanner.

Results = 0. 57 gph at idle in Park; and 1. 9 gph at idle in Drive with the brake on. (91 % DTT transmission)

This seems to tell me, to save fuel, I ought to be putting the transmission into neutral at stop signs, however, my transmission temp. goes up in neutral.

Bob in Sacramento

 

[RKohn]

Stop idling and Drive!!!

Your mileage will be much better.

 

[RBSOB]

Thanks for checking RobbyRam, thats about what some of us had figured, . 5 GPH. Still I would think there is a published rate somewhere. RKohn, unless you are WAY west of Kalamazoo,you must be doing some idling this winter Jim G.

 

[HC]

Originally posted by RobbyRam

I just checked the 'gallons per hour' at idle with my 'Cummins Quick Check II' Scanner.

Results = 0. 57 gph at idle in Park; and 1. 9 gph at idle in Drive

Great data!



Has anybody got an e-brake? I'd love to know the gph for "idle in neutral with e-brake on"! (I know its going to be more than 0. 57 gph, but by how much? 2 gph? 3 gph? more?

 

[Bigsaint]

Thanks, good info !!!



I don't idle because I want too ( except for quick warm ups after parking at work for 8+ Hrs. ) . I have no choice once winter hits and the girls need to go to the bus stop. I'm not going to make them walk and stand in sub-zero temps because I don't want to burn a little fuel .



Scott W.

 

[WeirCummin]

Trucks w/ autos will have a higher fuel rate due to the load of the TC.



Mine shows a idle fuel rate of . 42-. 48GPM cold and . 19-. 21GPM warmed up. This is all based on calculations for a stock CPL motor and is not actual fuel consumption.



I should have a chance today to get hooked up to a truck w/ a E-brake and I'll get some numbers.



Dean

 

[Steve Campbell]

Wiercummin......

Dean, this..... "Mine shows a idle fuel rate of . 42-. 48GPM cold and . 19-. 21GPM warmed up," ... . is an interesting difference. Does anyone know if the IAT is the main culprit here?

 

[WeirCummin]

Steve, Yes intake air temp and coolant temp both play a role in fuel consumption. There is an added "fuel quantity delivered" on a cold motor, it could be considered the same as a old carburetor engine with a choke.



I checked Jerry's (member NXS) truck with a E-brake. Fuel consumption was

Cold

. 42-. 51 brake off

. 40-. 53 brake on

Warm

. 22-. 24 brake off

. 41-. 43 brake on

With the brake on there is a 20RPM drop in engine speed and total load is increased to 4%

 

[Steve Campbell]

Another interesting set of #'s.....

"Cold

. 42-. 51 brake off

. 40-. 53 brake on "



Virtually no increase in fuel usage to warm up with the Exhaust brake when cold. This is good news!!!!



Next question,... . if I may... . , have you looked at fuel consumption with the engine idled up to 1200 RPM's or so?