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Posted

I'll add that the AFM stayed engaged quite a bit more than my 2013. IN my 2013, just about any load would cause it to switch back to V8. Today, the V4 would stay engaged even on gradual upslopes.

 

Another observation; in my RCSB you definitely feel a surge when it transitions back and forth.

Posted

What type of gas you guys put in your 2014 sierra or silverado? What mileage you think your getting.

Posted

There was a post on here a while back that explained why premium does help the mileage on these

new trucks, I cant find it maybe someone can???

If you can get gas without ethanol your mileage will definately increase!

Posted

Have you check actual mileage, you know with gallons used vs miles driven?

I had an Audi that always got great mileage according to the DIC, that was fine till I put pencil to paper.

Posted (edited)

Have you check actual mileage, you know with gallons used vs miles driven?

I had an Audi that always got great mileage according to the DIC, that was fine till I put pencil to paper.

All you guys interested in mpg should go sign up at Fuelly and start tracking it only about 7 of the 2014 1500 Sierras on there right now. http://www.fuelly.com/car/gmc/1500%20series/2014

Edited by MyFavTruck
Posted

Have you check actual mileage, you know with gallons used vs miles driven?

I had an Audi that always got great mileage according to the DIC, that was fine till I put pencil to paper.

 

How do you check how many gallons you have gone through? Is there a screen on the DIC that says it or do you have to wait till you fill up at the pump?

 

 

Sent from my iPhone using Tapatalk

Posted

How do you check how many gallons you have gone through? Is there a screen on the DIC that says it or do you have to wait till you fill up at the pump?

 

 

Sent from my iPhone using Tapatalk

I'm not sure of a gallons used info screen but your math will be much more accurate using the pump reading when filling anyway.

Posted (edited)
Have you check actual mileage, you know with gallons used vs miles driven?

I had an Audi that always got great mileage according to the DIC, that was fine till I put pencil to paper.

 

I'm self-employed so I've put pencil to paper (actually I use a spreadsheet) for every single tank for more than 20 years.

 

I know my numbers are accurate.

 

Let's look at my just done fillup. This one was mostly highway as I went out of town Friday.

 

286.8 miles / 19.603 gals = 14.62 mpg

 

So what I was seeing on the DIC in realtime looks a little optimistic.

 

Edited by bigsapper
Posted
Have you check actual mileage, you know with gallons used vs miles driven?

I had an Audi that always got great mileage according to the DIC, that was fine till I put pencil to paper.

 

How do you check how many gallons you have gone through? Is there a screen on the DIC that says it or do you have to wait till you fill up at the pump?

Sent from my iPhone using Tapatalk

 

I always use the information on the pump receipt along with the mileage on my tripmeter whenever I fill up.

 

Posted (edited)

My DIC has yet to be correct. The last 4 fill ups it's read 17.0 mpg. I get gas the same time every week, the same station (Sunoco) and same pump. When I do the math it's pretty much always the same. 300 miles driven,and 16 gallons to top off. 18.7 mpg. Winter blend (what a joke) too with 10% Ethanol. I'm hoping when the weather gets warmer, I'll see an increase. I noticed too on the 'pike when it shifts to V4 mode the mpg never changes.

 

I drive the same route every weekday and rarely drive it on the weekends. Half my drive is turnpike with the cruise set at 72,and the other half is a fairly congested twisty up and down 2 lane rural with stop lights at every crossroad. Lucky to average 35 mph. Mornings aren't bad as it's 5:30,but going home it can be pretty slow going.

 

I have a 2014 double cab 4x4 5.3 with the 3:42 rear. A little over 1,700 miles on the truck right now. I don't have any bed cover yet. Stock 18" GY tires, and basically an all stock truck. I'll have to do one of those 25 mile checks too.

It's still fairly cold here. Teens in the morning and not much above 40's in the day. I let my truck warm up for about 10 to 15 minutes in the morning and before I leave work.

I'm not a lead foot,but I'm not a granny driver either. Pretty gentle with the pedal. Someone mentioned DEFCO, whatever that is.

Edited by glc
Posted (edited)

This was on my drive home after i filled up ran about 60mph. This is on a sierra dbl cab 5.3L 4x4 18 in wheels with 3.08 rear. Also air temp was between 32-36°F.

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post-128368-0-01055900-1396190413_thumb.jpg

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post-128368-0-14192400-1396190282_thumb.jpg

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Edited by Dockellen
Posted

So does premium fuel give you better mileage with the new 5.3?

There was a post on here that I cant find that said somthing about

the new trucks computer being able to run different mapping if

premium fuel is used?

Posted

So does premium fuel give you better mileage with the new 5.3?

There was a post on here that I cant find that said somthing about

the new trucks computer being able to run different mapping if

premium fuel is used?

There is nothing in the factory calibration that can discern between different octane levels...

 

Better MPG on premium is possible though but not like you are thinking/hoping, let me explain-

 

You have 2 timing tables... One is a "High Octane" and one is a "Low Octane" timing table and this has been in factory calibrations for 20+ years. The low octane table is accessed when the knock sensors are activated for an extended period of time and is designed to keep your engine from being damaged due to detonation. I guess it is possible that with the higher compression that theses motors has, a poor quality fuel could be causing the low octane timing tables to be activated which will reduce power and cause poor mileage at the same time. With this being said, high octane fuel will probably not give you much better MPG but poor quality fuel can certainly reduce MPG's.

 

Steve

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