Useless Information

[swathdiver]

VVT equipped engines have Deceleration Fuel Cut-Off

The old Gen III LSs have it too, pretty sure mine does as well, no VVT. Cool technology.

 

[BG1988]

Thought this sticker was an interesting example of full disclosure on a fuel pump for E85. Surprised by the range of ethanol percentage they could have.
View attachment 236180

Ask inside they have a fact sheet or delivery sheet

 

[swathdiver]

Well, we may be getting close to new battery time. The ACDelco 48PS has been in the truck 3 years now, about 1500 hours and 40K miles. I haven't been driving much these past few months and the battery charge has been quite low lately. The last 4 times that we checked with the Tech-2 it was in the 50s, then 30s, then twice more in the 50s. A run down to Grandma's house a few days ago charged it up as on our return trip the alternator finally went into reduced charging state. My co-pilot had a headache so we didn't check the state of charge then. Will check it next time as we head out and keep an eye on it.

 

[swathdiver]

Truck sat until yesterday and the start up state of charge was back up to 63%. I unplugged all the USB adapters and the 12v adapter for the dash cam which has red light on it.

Ok, so two tanks of gas ago I filled her up with 93 octane from Chevron and two of their bottles of Techron. That tank had a lot of idling on it but still managed an average of 15.4 MPG with an alcohol content of 12%.

Then we refueled down south at another Chevron with 93 again (6%). On the trip north to home, the MPGs were 19.3 MPG by the time we pulled into the driveway. I've NEVER EVER NEVER seen fuel economy like that in this thing. We even hit some traffic and switched highways because of an accident.

Yesterday afternoon we made the same run down south and back north again in the evening. By the time we hit the highway she was reading 18.8 and struggling to stay there at 71 mph. But when I sped up to 73-74 the mpgs quickly climbed into the 19s and arrived at Grandma's at 19.3 MPG again. Somebody pinch me!

All that testing back in '17 and '18 never revealed a hint of this. My SV6 Montana gets better mileage the faster it goes but never seen that from this truck. On the way home however, my hopes were shattered, no matter how fast or slow I drove, the average mpgs kept dropping until it read 18.0 in the driveway. Still a record though.

Truck has some leaks and weeping underneath and have been slowly collecting parts and tools to replace seals and lines while watching the fluid levels. Still not enough to even mark up the driveway. Hope to get to it soon while the weather remains cool and hopefully stays dry.

Santa Claus has thus far gifted the truck an Inclination Sensor (17800432/22962506) for Christmas.

Merry Christmas fellas!

 

[swathdiver]

Start Up State of Charge yesterday was 64% after the truck sat for about 14 hours. Ran South for about an hour, sat for 4 hours and it was 70%. Forgot what it was when we returned home. Will check tomorrow. ACDelco 48PS is 40 months old now and has 40,958 miles and 1458 engine hours on it.

 

[swathdiver]

Start Up State of Charge this afternoon was 53%. Truck has not been driven since the 27th. Started just fine, nothing was left plugged in. Battery to me it seems is just about wore out. What do you fellas think?

 

[wjburken]

Sure seems like it’s heading that way.

 

[kbuskill]

Start Up State of Charge this afternoon was 53%. Truck has not been driven since the 27th. Started just fine, nothing was left plugged in. Battery to me it seems is just about wore out. What do you fellas think?

These trucks, with all the different "computers" and modules, do have a lot more parasitic draw than the older vehicles, that is for sure.

I've never really paid attention or kept track of what the state of charge is on the Burb's battery so I'm not sure what "normal" is.

 

[swathdiver]

These trucks, with all the different "computers" and modules, do have a lot more parasitic draw than the older vehicles that is for sure.

I've never really paid attention or kept track of what the state of charge is on Burb's battery so I'm not sure what "normal" is.

I barely paid attention too. I can say that that since owning it, the Start Up State of Charge was always in the 70 percent range (when I bothered to look). Same for regulator set point (70s- low 80s) and such.

Happy New Year Folks!

 

[Sam Harris]

Happy New Year!!

 

[swathdiver]

Last tank of fuel averaged 17.47 MPG over 418.4 miles to that tank, burning 24 gallons even. Average speed was 47.61 MPH for those seven 55 mile highway runs and a little more. Pretty sure those are records or near so for this rig. DIC showed 17.7 MPG after heavy traffic to get to the pump.

Had a midnight run to make so I crawled out of bed, loaded up on meds and filled her up. Took on 8 gallons of E85 and almost 18 gallons of E15/Unleaded 88. Hit the highway for a spell and the alcohol content settled down to 26% (predicted) and was getting 20 mpgs on the highway. During the midnight run, the fuel composition went active and reset the alcohol content to 29% and mileage dropped to the 17s, LTFTs were at zero before at 26% and took a while to zero out again at 29%. I like the old setting better! Wish I could change it back and recover those 3 mpgs!

Good weather ahead for working on the vehicles but I've been sick and my little helpers are sick and have bad backs from helping their Grandma move furniture. We shall see.

This pic is for you Brent:

 

[Tonyrodz]

Happy New Year James.

 

[Big Mama]

Does sound like the battery is weakening some. Wishing I could run some E85 as a test. Happy and safe new year to all.

 

[Tide]

Is 8 gal of E85 and 18 of E15 your typical fill up?
What’s the price difference between the two where you are?


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[swathdiver]

Is 8 gal of E85 and 18 of E15 your typical fill up?
What’s the price difference between the two where you are?

Don't think I've established a typical mix yet. Still experimenting. The goal this time was to run an alcohol content of 26% and an octane rating of 93. On that particular day, E15 was $2.43 and E85 was $2.26.

In October I ran a similar mix, substituting the E15 for 93. Alcohol content was 19% with an octane rating of about 96. Mostly city driving delivered 14.9 MPG for that tank. The very next one capitalized on the old fuel, went with 22 gallons of E15 and 4 of E85 for a 20% alcohol content. MPG for that tank was 16.4 and the average speed was 10 MPH higher than the previous at 43 MPH. That tank cost just under $61 which worked out to fourteen cents a mile.

January through May of last year we had the truck exclusively on E30, or so we thought/tried. The pump at this particular station was advertised as E30 but never saw more than 25%, which was fine by me, but over time it was less and less, at one point it was basically E10 and 87 octane. I suspect that when I refueled on the overnight that the blender pump was turned off.

Anyhow, we determined with all those tanks that the motor liked between 11%-20% better than E10 or anything higher as far as gas mileage.

What are you doing and has been your experience?

 

[Sam Harris]

Don't think I've established a typical mix yet. Still experimenting. The goal this time was to run an alcohol content of 26% and an octane rating of 93. On that particular day, E15 was $2.43 and E85 was $2.26.

In October I ran a similar mix, substituting the E15 for 93. Alcohol content was 19% with an octane rating of about 96. Mostly city driving delivered 14.9 MPG for that tank. The very next one capitalized on the old fuel, went with 22 gallons of E15 and 4 of E85 for a 20% alcohol content. MPG for that tank was 16.4 and the average speed was 10 MPH higher than the previous at 43 MPH. That tank cost just under $61 which worked out to fourteen cents a mile.

January through May of last year we had the truck exclusively on E30, or so we thought/tried. The pump at this particular station was advertised as E30 but never saw more than 25%, which was fine by me, but over time it was less and less, at one point it was basically E10 and 87 octane. I suspect that when I refueled on the overnight that the blender pump was turned off.

Anyhow, we determined with all those tanks that the motor liked between 11%-20% better than E10 or anything higher as far as gas mileage.

What are you doing and has been your experience?

So I’ve been running e85 exclusively for a while now. I’ve been enjoying the power, but not the mileage (11.5) I haven’t really experimented with any blending, and I don’t religiously check mpg, average speeds, etc.. I typically do way too much city driving as well. I just got my Tech2 yesterday, and was quite surprised to see the fuel alcohol content at 78%. I figured you’re the guy to ask:
1. I was surprised it’s this high, is that expected?
2. Are there any detrimental effects to having higher content like this?

I enjoy reading your detailed analyses, and appreciate the effort you put into it, and that you share with us. [emoji106][emoji16]

 

[swathdiver]

So I’ve been running e85 exclusively for a while now. I’ve been enjoying the power, but not the mileage (11.5) I haven’t really experimented with any blending, and I don’t religiously check mpg, average speeds, etc.. I typically do way too much city driving as well. I just got my Tech2 yesterday, and was quite surprised to see the fuel alcohol content at 78%. I figured you’re the guy to ask:
1. I was surprised it’s this high, is that expected?
2. Are there any detrimental effects to having higher content like this?

I enjoy reading your detailed analyses, and appreciate the effort you put into it, and that you share with us. [emoji106][emoji16]

Your welcome and I learn from these pages just like everyone else. No, not unusual after you've run a few tanks, sixty five percent of my E85 fill up are over 70%. Four at 80%, the highest recorded. The mileage isn't great but it comes down to cents per mile besides power and fun!

Now being that you are in Denver, I would have thought that they would have shifted over to winter blend which is 70% by now. You can look up the dates on Department of Energy website. We do not or are not supposed to get winter blend down here.

The only bad thing I noticed, if you can call it that, was that emissions related issues would reoccur more frequently on Ethanol. When my cats were going bad a few years back, the CEL would come on sooner when running E85 compared with 93. And more recently, I would get those EVAP system leak codes more often too. Since I switched back to 93 and now low alky content ethanol mixes, the CELs have not returned but I get the gas cap message sometimes. May not be related though. Not going to deter me from running it.

Prices are coming down but not under $2 a gallon yet. It costs me nineteen to twenty cents a mile here to burn E85 while the E20-E30 is seventeen and eighteen cents a mile on average. Sometimes it's down to thirteen and fourteen cents which is awesome! Straight up 93 costs over $80 to fill the tank, E85 or blends are about $20 less. That's taking my wife out for ice cream money!

I would like to run E85 more often but often need the 400+ mile range between refuelings. Best the truck has done on E85 is 340 miles and can almost always get to 300.

Oh, good to see you got a Tech-2. Best tool in my garage.

 

[Tide]

You are way more analytical than I am about this. There are way too many variables for me to give any significant input on the subject.

I do know that E85 isn’t worth it for me even though it is my preferred fuel. My MPG tanks to 9.5-11.5. With E15 I’m averaging 3-4mpg higher.

It’s hard for me to keep my foot out of it since the headers have been installed. I really need to get it tuned and see what happens.




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[Sam Harris]

You are way more analytical than I am about this. There are way too many variables for me to give any significant input on the subject.

I do know that E85 isn’t worth it for me even though it is my preferred fuel. My MPG tanks to 9.5-11.5. With E15 I’m averaging 3-4mpg higher.

It’s hard for me to keep my foot out of it since the headers have been installed. I really need to get it tuned and see what happens.




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Haha! Same here. Tune is the next item on my list. The ARH longtubes make such sweet music!

 

[gooffeyguy]

If you have to run premium fuel (93 octane), the 2-3 mpg difference still comes out cheaper when only paying $2 per gallon versus $3.


2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18