Jump to content

Recommended Posts

Posted

I don't know if it's been said in here but with regular gas I was getting roughly 14 mpg don't know the exact number. Then I put premium in and it bumped up to 16.1. I was very surprised

Posted (edited)

Premium OH MY GOSH that costs extra cash!!!!!!!!!!!!!! LOL I thought about it but right now I have been running a few tanks of nonethanol 87 octane. Now this last tank I filled up with 10% ethanol 87 octane. Next 3 to 4 tanks will be E85 I did not want to shock the trucks system with all that alcohol and get it drunked up so I am running a tank of 10% before I blast it with the E85. Might try some Premium fuel at some point but I am hoping that these new engine controllers can tune the engine to burn the E85 just as efficiently as the nonethanol fuel. In the past they have not been able to get nearly as good of gas mileage on the E85 it just sounds counter intuitive to me that the E85 produces more Horsepower but burns less efficiently but I never got goods grades is science in school so I guess I just do not have the needed mental capacity to understand that. Several trucks on the Fuelly site now so if they actually keep their data entered correctly we should be seeing real world results pretty soon.

Edited by MyFavTruck
Posted

Something of interest:

I record the gallons used, the odometer reading, and the trip computer’s mpg report. Given the vagaries of filling a gas tank to exactly the same level at each fill-up, some variability is understandable.

 

Mark Allen, GM’s director of global energy, mass, and aerodynamics, says some inaccuracy is unavoidable. “The density of fuel varies. We have no way to measure it. Mobil might be different than Shell. Summer gas to winter gas could be a big difference.” And then there are vapor-recovery systems. With modern cars’ sealed fuel tanks, gasoline vapor accumulated in the tank is absorbed by a charcoal-filled canister. Periodically, this canister is purged by the engine. “If the weather is hot, you generate lots of purge,” says Allen. “This unmetered fuel isn’t counted by the trip computer.”

Posted

 

 

First highway trip with the Denali 6.2:

 

IMG_20140222_131712_036.jpg

 

I have 34" tires and have not corrected the computer. Adjusting for the 7.4% error the actual numbers are 17.3 MPG at a 68 MPH average.

 

This was a round trip from the Seattle area to the top of Snoqualmie Pass (3000 ft elevation) and back again. The engine is still new (fewer than 300 total miles).

 

I'm pretty happy with that. It's rated at 20 for the highway, I've taken off the front airdam, lifted it 2" front, 1" rear, and put much bigger and heavier 34" tires on it.

 

IMG_20140222_110255_144.jpg

 

 

 

I repeated the same trip above. The truck now has about 1500 miles on it so it's a bit more broken in. I have also corrected the speedo for the tire size and I've disabled AFM completely.

 

IMG_20140309_134724_904.jpg

 

IMG_20140309_140443_076.jpg

 

IMG_20140309_140459_389.jpg

 

IMG_20140309_140511_692.jpg

 

IMG_20140309_140420_590.jpg

 

So without the AFM it got 18.1 on the same trip. I calculated by hand as well and it was within .05 MPG (although doing that for such short trips is not very accurate). The engine is a bit more broken in, but I'd say most of the gain was from the simple fact there was less traffic this time.

 

The 400 mile average has several weeks of city driving and since I only live 3 miles from work I only get about 11 MPG on that daily commute.

Posted

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

Posted (edited)

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

Any deep North boys noticing this?The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

Any deep North boys noticing this?

 

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

post-127624-0-18038400-1394437538_thumb.png

post-127624-0-18038400-1394437538_thumb.png

post-127624-0-18038400-1394437538_thumb.png

post-127624-0-18038400-1394437538_thumb.png

Edited by Ton J
Posted

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

 

What are those other test fuel types? I don't touch E85.

Posted

 

What are those other test fuel types? I don't touch E85.

All the test GM did on the Silverado an other trucks before release on the market. as you can see the results of the test. real world. here is the list trucks they by model. based California Emission test but it shouldn't matter because they have the toughest laws on this stuff

post-127624-0-97386500-1394462383_thumb.png

post-127624-0-97386500-1394462383_thumb.png

post-127624-0-97386500-1394462383_thumb.png

post-127624-0-97386500-1394462383_thumb.png

Posted

I almost agree with that statement but its doest get that cold here to much and ive had this problem since the first update which first week of Jan and weather here was pretty good. But I did find emission test from California that General Motors did on the truck and should after 4000 miles and 10 road test 2wd 5.3L 2014 Silverado 12.4mpg in the city on reg. And 17mpg on hwy. Am going upload the page later. And it shows the EPA at 16mpg in city 22mpg hwy but no testing info.

 

 

What are those other test fuel types? I don't touch E85.

Top 2 are E85

3 one is unleaded

bottom one are EPA standard that you see on the window.

Posted

 

Top 2 are E85

3 one is unleaded

bottom one are EPA standard that you see on the window.

Little more info

post-127624-0-27850300-1394463167_thumb.png

post-127624-0-27850300-1394463167_thumb.png

post-127624-0-27850300-1394463167_thumb.png

post-127624-0-27850300-1394463167_thumb.png

Posted

dealer called afm system was effected by updated and they said instead of using less Gas it's using more. And GM tech heads can't figure it out. Update did something to system.

Posted (edited)

I wish you were closer so I could get a copy of your calibration, then I could see how much different it is from mine. My MPG is everything that GM claims if I'm actually driving like an adult. It's hard to keep my foot out of it though since I started tuning.

 

It's good to hear that they are working on your issue, I hope you get it resolved in a timely manner. I would hate to see you down at the ford dealership because GM is dragging there feet.

Edited by iCryWheniGoPoop
Posted

I wish you were closer so I could get a copy of your calibration, then I could see how much different it is from mine. My MPG is everything that GM claims if I'm actually driving like an adult. It's hard to keep my foot out of it though since I started tuning.

 

It's good to hear that they are working on your issue, I hope you get it resolved in a timely manner. I would hate to see you down at the ford dealership because GM is dragging there feet.

You crazy as hell, Ill never buy a Ford. Ill stay with Chevy problems and all I just want it fixed. It was just fine when I first got it. Chevy to end man.

Posted

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

 

Exactly the same here. The other morning it was -12c or so, warmer than what weve been experiencing lately but same fuel economy as usual. It kept warming up to -5c and on my way home I beat my pathetic 50km record set on my second tank of fuel ever. Nice and warm today, just above melting, and I am probably using 25-30% less fuel than I ever have.

 

WFT is up with that? It's like a switch was flipped at -5c.

Posted

 

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

The last 2 days 90% city driving and I'm hitting 16 mpg. When I say city I talking 35 to 45 kph and lights every 1/4 to 1/2 mile. Same driving I always do...From 11 to 16. The only difference...TEMPERATURE! Instead of low 20th and high teens...it's was high 30s low 40s here in mid Michigan.

 

Any deep North boys noticing this?

 

Exactly the same here. The other morning it was -12c or so, warmer than what weve been experiencing lately but same fuel economy as usual. It kept warming up to -5c and on my way home I beat my pathetic 50km record set on my second tank of fuel ever. Nice and warm today, just above melting, and I am probably using 25-30% less fuel than I ever have.

 

WFT is up with that? It's like a switch was flipped at -5c.

 

EXACTLY! GM needs someone looking at this...even though the southern boys in this thread think we're nuts...this is a real issue in the cold!

 

Where is the GM service Rep? They seem to show up in every other cotton picking thread on this site?!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts
  • Member Statistics

    342,759
    Total Members
    8,960
    Most Online
    DM22
    Newest Member
    DM22
    Joined
  • Who's Online   3 Members, 0 Anonymous, 2,564 Guests (See full list)


  • Latest Articles

  • Posts

    • I thought I would use your thread and add to it as I just did my first longer drive with my truck in the last couple of days. I drove from the Grande Prairie area of Alberta down to Edmonton and most of where I drove in the city was the ring road so fairly free flowing but a bit of stop and go as well in the city. Stayed the night and returned home and not too many stops along the way each way but every restart and certainly every cold start sets it back for fuel mileage. Why I say that is I see some people will cherry pick a fuel mileage leg after the vehicle had been warmed up driveline wise before hand and its a forgiving ( easy rolling drive leg for example ) and call that their fuel mileage which can give a false perception of reality. I was not heavily loaded at all but never the less the flip bak cover, rubber bed mat, various tools etc and extra jerry cans of fuel all way up to a few hundred pounds of dead weight so its not an empty truck. The cold inflation tire pressures are set more near the freezing point so once they are warmed up driving I was showing 45 front and over 40 rear and realize high inflation pressures would help a little in fuel mileage but certainly not the ride on our crap sections of highway. The weather was good so was not raining as that can really drag mileage down, in fact I had a bit of a tail wind on average driving home. Most people on here would never have driven on that freeway to visualize it but its got a fair bit of rolling type of landscape with numerous river valleys. For the most part I had it on cruise set to 62 although kicking it off if I caught it in time before it started down shifting and self braking going down the grades. Most of the more substantial grades its shifting into 7th I believe as 8th just doesn't have it. Total distance round trip was 643 miles and my overall average and I did refuel three times in all, figured out to 17.65 miles per US gallon. My best fuel mileage section refuel within all of this figured out to 18.46 and these are all hand calculated figures. I find if anything that the trucks computer can be over optimistic, sometimes its pretty close but other times its stretching it. On paper persay in theory the truck would have just about made it on fumes for that whole drive without refueling once.    Which made me think of the topic thread of the wonder if these trucks could do 20 mpg and that is a good question, certainly would have to be on an easy going flat highway, no head wind, the right temperature, not packing around a bunch of dead weight and puttering along even slower than I was I would suspect and going steady and not stopping to smell the flowers or take a piss !. It probably is possible but not without effort to attain that with the wind resistance and weight of these trucks. Of course on my drive most people are passing me if they have the power as per loaded highway tractors, never mind a lot of speedy vehicles but the speed limit is 68 and most are at or well over that. 
    • Monday looks like a good day for the dealer to test an ac issue. Hopefully it all turns out good.
    • Paid $2.72 for E85 today.
    • Welcome back! No, it definitely doesn't pass the sniff test. Even "ceasefire" needs an alternative definition these days.    $5.29 at Kroger today
    • That makes sense, and I think you are describing the real product problem. Capturing data is the easy part. If the owner or technician has to manually dig through five minutes of millisecond-level logs, the product has already failed. The device would be at the ECM harness, not at the OBD port, so I agree that data retrieval and event marking need to be thought through carefully. The way I am thinking about the architecture is: The recorder itself should not depend on a phone, app, Bluetooth, Wi-Fi, or cloud connection to capture the event. It should always keep a local rolling buffer and lock the event locally. A button, phone app, or small cabin device would only act as an event marker. If the driver feels a stumble and presses the button 10–30 seconds later, the pre-buffer has to already contain the useful data. For data retrieval, the practical options would be a sealed service USB lead, Wi-Fi download, or a phone/cabin companion device. I would not expect the owner to remove the ECM-side module or work with raw files directly. The cloud or AI side would be for interpretation, not for capturing the event. The truck may have no connection when the issue happens, so the evidence has to be saved locally first. After that, cloud processing could help decode the data, compare it against baselines, and generate a readable report. For the first version, I would keep the automatic triggers conservative and objective: driver event marker bus-off error passive voltage drop / brownout device reset FIFO or queue overflow a normally periodic message disappearing side-to-side communication mismatch, if the topology supports that For “learning normal,” I agree with your point, but I would not want to overclaim it as automatic root-cause diagnosis at first. A realistic first step would be learned baseline comparison for that specific vehicle and operating condition. For example, a value would only be compared against similar conditions: RPM range load / MAP throttle position gear / vehicle speed coolant and oil temperature battery voltage AFM/DFM state, if decoded and validated Then the report could flag things like: this periodic message disappeared compared with its normal timing this value deviated from this vehicle’s normal range under similar conditions the same abnormal pattern repeated after the same type of event the anomaly occurred together with voltage, oil-pressure, misfire, or communication changes But I would still call that “abnormal pattern detected,” not “replace this part,” unless there is enough validated repair data behind it. So the intended product would not be “here is a huge log.” It would need to be an event package: what triggered the capture how much pre/post data was preserved what changed before and after the event whether the device itself reset, overflowed, or saw a bus error selected graphs around the event raw data only as supporting evidence From your perspective, what would make this kind of report useful instead of just another datalog? For example: What are the top 5 parameters or events you would want highlighted first? Would you trust a learned baseline for that specific vehicle, or would you prefer fixed thresholds? How much false-positive flagging would be acceptable before you stopped looking at the reports? What would a one-page report need to show for an independent shop to take it seriously? For misfire, AFM/DFM, oil pressure, or U-code complaints, what would you want the tool to flag automatically?
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...