MPG Issues with 6.2 Denali

[bdbake01]

WRONG! He has a 6.2! It needs premium! If you have a 14 6.2, I advise the same

NEED is a strong word. Yes, it will most certainly have more power and better mileage w/ premium. Proven fact, and for good reason. Is 87 cheaper dollar for dollar, mile for mile? Well, quite possibly depending on your local price of gas. But it will run on 87.

 

Here's my take on it though. First, it has to knock first to drop to the lower timing maps. Knock=damage over time, not something I want to subject my baby to. Second, I paid an additional $2K USD to have a 6.2, not a 5.3. Why would I muzzle a 6.2 back to near 5.3 levels with bad gas? If I knew it would be hard to get but want the power, get a 5.3 and $2K worth of go fast mods.

[iCryWheniGoPoop]

NEED is a strong word. Yes, it will most certainly have more power and better mileage w/ premium. Proven fact, and for good reason. Is 87 cheaper dollar for dollar, mile for mile? Well, quite possibly depending on your local price of gas. But it will run on 87.

 

Here's my take on it though. First, it has to knock first to drop to the lower timing maps. Knock=damage over time, not something I want to subject my baby to. Second, I paid an additional $2K USD to have a 6.2, not a 5.3. Why would I muzzle a 6.2 back to near 5.3 levels with bad gas? If I knew it would be hard to get but want the power, get a 5.3 and $2K worth of go fast mods.

NEED is not a strong word when you tune these things on a regular basis and constantly see KR even on 93octane, I should have said "Don't be a dumbass, run 91 or higher" maybe that would strike a nerve, NEED is a fact! If replacing the moving parts that occupy your cylinder bores comes easy to you and money is no object, by all means, run 87 in the 2014 6.2 that has 11.1 compression. yes, the ECU does a good job pulling timing to accommodate for the Knock, but it's not designed to do it for the life if the truck, well... I take that back, it will do it for the life of the truck, however short that may be.

[mojo85]

I won't be coming anywhere near 93 octane, heck i've rarely seen it in the cities here but I am glad 91 is available

[iCryWheniGoPoop]

I won't be coming anywhere near 93 octane, heck i've rarely seen it in the cities here but I am glad 91 is available

 

They run well on 91, the 6.2's I have tuned on 91 just had knock at light or no loads running on the stock timing tables, a good MAF recalibrationband some minor changes in the timing table I am normally able to reduce that quite a bit. On occasions where knock was bad, I could simply suggest changing fuel and it would help tremendously (Wally World fuel was 2 of culprits in such cases)

Listen Guys, The fuel door simply states to use premium fuel only, when you run 87 and complain of fuel mileage and low power, then you only have yourself to blame. Chances are you are running at timing tables that are nearly cut in half from the timing table you would normally be running on if you did just like GM suggested. You WILL see power gains and fuel mileage increases with premium fuel in the 2014 6.2 and the peace of mind knowing that if a knock sensor fails, your truck will continue to chug along as it should with little to no threat of cylinder damage.

 

Just my .02, it's your truck.

[dodgehemi0]

 

Northern Canada

Oh I lived in fairbanks AK for years

 

 

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[bdbake01]

NEED is not a strong word when you tune these things on a regular basis and constantly see KR even on 93octane, I should have said "Don't be a dumbass, run 91 or higher" maybe that would strike a nerve, NEED is a fact! If replacing the moving parts that occupy your cylinder bores comes easy to you and money is no object, by all means, run 87 in the 2014 6.2 that has 11.1 compression. yes, the ECU does a good job pulling timing to accommodate for the Knock, but it's not designed to do it for the life if the truck, well... I take that back, it will do it for the life of the truck, however short that may be.

Dude, I'm on your side. I did say knock=damage over time. My point was that "need" sounds a lot like "won't run without". Which, clearly it will, but just because something will do something doesn't mean you should subject it to the damage day in and day out. Since it runs on 87, some will assume that it's fine. It'll probably also run on 80 and maybe even whiskey.

 

Both bad ideas btw.

[mojo85]

Im about the north, 24hr daylight soon

Dude, I'm on your side. I did say knock=damage over time. My point was that "need" sounds a lot like "won't run without". Which, clearly it will, but just because something will do something doesn't mean you should subject it to the damage day in and day out. Since it runs on 87, some will assume that it's fine. It'll probably also run on 80 and maybe even whiskey.

Both bad ideas btw.

Got it, truck will run on whisky. Next fillup will be 87 and Jack Daniels

[bdbake01]

Im about the north, 24hr daylight soon

Got it, truck will run on whisky. Next fillup will be 87 and Jack Daniels

That would be a despicable waste of JD. To each his own!

[Newm]

Here is a question......if you could choose 91 octane with no ethanol or 93 octane with 10% ethanol what would you pick? Always wondered. I have run 91 ethanol free premium since day one but might try BP's 93 and see if I can see a mpg change.

[Crf450r420]

Here is a question......if you could choose 91 octane with no ethanol or 93 octane with 10% ethanol what would you pick? Always wondered. I have run 91 ethanol free premium since day one but might try BP's 93 and see if I can see a mpg change.

I'd run 91 no ethanol if I could get it. The truck will make the most power with the lowest octane fuel it can run without knocking. Then the extra 5 percent of energy in every gallon you will get the best MPG and HP that way. Now I don't know the cost difference and it might not add up for bean counters. I won't run anything with ethanol if I don't use it often or it has a carb, so my trucks get pump gas and cars, bikes, and lawn equipment get non ethanol. The extra trip across town with 10 race jugs to get the fuel beats the rebuilds and repairs of having that crap setting in your system.

[bdbake01]

91 unless it sits for long periods of time, then 93.

[Crf450r420]

The other way around. The 91 he saying has no ethanol and the 93 has it. I give ethanol a shelf life of about a month and normal gas about a year. You use to be able to take a bowl of gas to clean a carb and leave in on a bench overnight, but still clean with it. Now take a small bowl and fill with 10% and then fill the other with 0%. Don't walk away because unless you have no humidity in the air you are going to see moisture swirl into the 10% in about 15 minutes or less. The 0% will sit for days and not happen. Any remember the STP bottle to get water out of you tank? It was alcohol and it would mix with the water to help you burn it out if you didn't have to much. Now they are putting in you gas so your fuel absorbs water in to the alcohol from the air. It's junk and if I had a better source I would only run 0%.

[bdbake01]

Fuel absorbing alcohol from the air. Cool trick.

 

My concern was octane loss, not volume loss or water absorption.

[Mark L]

Question for those with the Denali gauge cluster......

 

Since ours is a digital gas gauge, are you finding the low fuel warning is coming on prematurely?

 

As shown in my post above, I averaged 20.8 MPG coming back from San Diego and the low fuel light came on when I was approximately 10 miles from my house.

 

I searched through the Denali manual, but didn't see anything stating how much fuel is left when the low fuel warning light comes on. I heard someone mention 2 gallons, which at my MPG level, would mean I had nearly 42 miles of range left. When the light first came on, it did state a range of 56 miles, then gradually went down, until it just stated fuel range "low".

 

How it went from 42 mile range to low is beyond me. What is low supposed to mean? 5 miles? 10 miles?

 

So here I am coasting to my driveway thinking I could run out of gas at any second and long story short, I put gas the next day and it only takes 23.XX gallons

 

So that tells me I had 2 gallons and change in my tank. Here I was thinking I would run out.

 

The reason this is such a big deal to me is because I will be making this roundtrip to San Diego quite often in the near future and it is exactly 458 miles door to door for me (and I HATE HATE HATE to stop on road trips, literally will not stop if I'm by myself). Simple math tells us a 26 gallon tank @ at least 20 MPG (which I averaged to and from) should net me a range of 520 miles. Yet as shown above, my trip meter read 465 miles on the return trip with the low fuel level warning triggering and the range stating just "LOW".

 

So am I to believe I still had a range of 55 miles even when the fuel range stated low? Based on the exact math, that's what the range should have been.

[bass mechanic]

Question for those with the Denali gauge cluster......

 

Since ours is a digital gas gauge, are you finding the low fuel warning is coming on prematurely?

 

As shown in my post above, I averaged 20.8 MPG coming back from San Diego and the low fuel light came on when I was approximately 10 miles from my house.

 

I searched through the Denali manual, but didn't see anything stating how much fuel is left when the low fuel warning light comes on. I heard someone mention 2 gallons, which at my MPG level, would mean I had nearly 42 miles of range left. When the light first came on, it did state a range of 56 miles, then gradually went down, until it just stated fuel range "low".

 

How it went from 42 mile range to low is beyond me. What is low supposed to mean? 5 miles? 10 miles?

 

So here I am coasting to my driveway thinking I could run out of gas at any second and long story short, I put gas the next day and it only takes 23.XX gallons

 

So that tells me I had 2 gallons and change in my tank. Here I was thinking I would run out.

 

The reason this is such a big deal to me is because I will be making this roundtrip to San Diego quite often in the near future and it is exactly 458 miles door to door for me (and I HATE HATE HATE to stop on road trips, literally will not stop if I'm by myself). Simple math tells us a 26 gallon tank @ at least 20 MPG (which I averaged to and from) should net me a range of 520 miles. Yet as shown above, my trip meter read 465 miles on the return trip with the low fuel level warning triggering and the range stating just "LOW".

 

So am I to believe I still had a range of 55 miles even when the fuel range stated low? Based on the exact math, that's what the range should have been.

fill up a 5 gallon gas can in the bed and run the truck dry, then you'll know the answer you seek.