How Low Can You Go?

SEMIJim

Original poster
Member
Apr 13, 2013
116
On the fuel gauge, I mean :smile:

New-to-me 2007 TrailBlazer LS. Dealer had the gauge cluster refurbished. Next fillup will be my 4th, and I thought, once the guage got down below 1/4, maybe it wouldn't be a bad idea to see about how low it'll go. Figured I'd hate to be out in the middle of nowhere, with no cell coverage, and find that something a bit over "E" was really empty :wink:.

So right now it's about dead on the "E" mark. The low fuel light is not yet on. (It does work. I've seen it light on start.) The needle rests just shy of the "E" mark with the truck shut down.

So just how far can I (probably) push my luck, do y'all think?

Thanks,
Jim
 

fletch09

Member
Nov 20, 2011
1,982
on my 09, i have the DIC, and when i'm getting close to low, i check the "range"
from my experience once the low fuel light comes on, the range has dropped below 50 mi.
the range will depend on driving habits of course. :twocents:
 

CaptainXL

Member
Dec 4, 2011
2,445
SEMIJim said:
maybe it wouldn't be a bad idea to see about how low it'll go.

I wouldn't want to find out. I personally have never ran out of fuel in my vehicle. But when I do fill up in those rare times it does light up it seems to take about 22 gallons. This would be about 3 gallons or 50 miles left in a 25 gallon tank.

Running the fuel pump dry can cause it to fail much easier than you might think. So I am very leery of this.
 

Boricua SS

Member
Nov 20, 2011
3,080
Ohio
I don't go lower then a half a tank in my SS... gas for me is over $4 a gallon (93 octane) so it hurts the wallet less filling from half a tank rather then under a quarter tank...
 

CaptainXL

Member
Dec 4, 2011
2,445
Boricua SS said:
I don't go lower then a half a tank in my SS... gas for me is over $4 a gallon (93 octane) so it hurts the wallet less filling from half a tank rather then under a quarter tank...

Have you tried using lower octane? Unless your street racing all the time you might want to try it out and see if it pings a lot.
 

SEMIJim

Original poster
Member
Apr 13, 2013
116
Okay, guys. Thanks for the ballpark estimates.

Sounds like 2-3 gal., which would be about 30-50 mi., depending. That'll be more than enough. My daily commute is only 17 mi. each way.

I don't plan on letting it run dry. I was just curious how low the gauge would go, in practice, and when the low fuel warning would come on.

Jim
 

Playsinsnow

Member
Nov 17, 2012
9,727
I believe my owners manual states the gas light comes on with 1.8 US gallons remaining. Most vehicles gas light illuminate around 2 gallons. Range varies from 33ish to 27ish depending on the time of year. I've always kept total engine run time to under 30minutes, watching both miles and gals consumed on my DIC. Most I've ever refueled was 20.5gals on a road trip. 21.7 gal tank. It helps that I only put on about 60 miles a week now :biggrin:

I've also had my gas light come on going downhill with over 50miles on the range. Sometimes when I question how low it is, I will park facing uphill at any angle to see if the gas light comes on immediately, get gas now or closer to home...
 

Bad Bowtie

Member
May 15, 2013
13
jrSS said:
Around 300 miles on a full tank.


I definitely get more than 300 per tank. I usually get around 370-390 out of mine but I drive it pretty gently.
 

Grimor

Member
Mar 28, 2013
954
I get about 346 out of a tank to where a fillup is about 21 gallons.

You don't want to run low too often, no gas means no lube for the pump and more likely for it to die on you.
 

Playsinsnow

Member
Nov 17, 2012
9,727
Grimor said:
I get about 346 out of a tank to where a fillup is about 21 gallons.

You don't want to run low too often, no gas means no lube for the pump and more likely for it to die on you.

my gas light has come on at least once every two wks minimum for the last two years (times are tough rt now-life is good but tough). Buddy warns me of dirty tank, pump fail etc but I guess I've been blessed after what I put my TB through. I've gotten 260miles hauling straight through and over 440 range+trip on full tanks nonstop. Depends on the time of year and my mood I guess.
 

DDonnie

Member
Mar 26, 2012
2,631
someone changed the name of this thread... LoL.
 

ScarabEpic22

Member
Nov 20, 2011
728
CaptainXL said:
Have you tried using lower octane? Unless your street racing all the time you might want to try it out and see if it pings a lot.

No, and I never will. The LS2 is rated for premium fuel for a reason, higher compression and aggressive timing (it's pretty aggressive from GM actually, but there is still a little room for improvement). You theoretically could, but a few bucks for higher performance AND not having to worry about blowing up a 6k motor is good enough for me.

Heck, every I6 Ive tuned except for 2 all run 91+ octane. Get 10-15hp more, holds 4th lockup longer on grades (more torque available), doesnt knock, and gets ~1-2mpg better than the 87 tune (I spent a lot of time testing it on my 02). Every I6 Ive logged has anywhere from 3-5* of knock with 87 octane, they really need at least 89 to run without knocking. Every I6 87 octane tune has 3*+ of timing removed from the high octane maps because they knock so much.


As for the fuel gauge, Ive had both of TBs fuel needle below the E hash mark and been ok. I have run out of gas once in the SS, never in the 02. I try not to run them that low as it's bad on the fuel pump, but on long road trips sometimes it happens.
 

CaptainXL

Member
Dec 4, 2011
2,445
ScarabEpic22 said:
No, and I never will.

Then don't mention how much gas costs. lol. It makes me sick. You bought an expensive car. And have a tune which uses more expensive gas. So WTH? Looks like you can afford the gas.

Paying for 93 octane is what? $200 more a year? For your car it's worth it.

BTW, I have read that people with corvettes straight from the factory run 87 in their LS2's and they have no knocking.
 

seanpooh

Member
Jan 24, 2012
461
If I got on E on the gauge and checked the DIC for the range, it says LOW. I know the range becomes low when I fall under 32-35 miles left as a range. I would say I've tested it out when I got the E yellow light for about 20 miles before filling up. You would also know if the gas station rigged their pump if you pump more gas than your tank can hold...


Now that the air is warmer, my transfer case is swapper, new cat, new ignition coils and 02 sensors, I can go ~500 miles hwy on a tank (XL 26 gallons) cruising 55-60mph.
 

CaptainXL

Member
Dec 4, 2011
2,445
That's about what I get. 19mpg X 26 = 494.

Realistically I get 400ish miles between fillups. My light comes on with 3-4 gallons left in the tank
 

Grimor

Member
Mar 28, 2013
954
Playsinsnow said:
my gas light has come on at least once every two wks minimum for the last two years (times are tough rt now-life is good but tough). Buddy warns me of dirty tank, pump fail etc but I guess I've been blessed after what I put my TB through. I've gotten 260miles hauling straight through and over 440 range+trip on full tanks nonstop. Depends on the time of year and my mood I guess.

I don't really consider the gas light low, that's just the reminder to get gas (still gallons of gas in the tank). Low would be where you're wondering if you'll make it the 4 blocks to the gas station and which side of E really means empty.
 

Playsinsnow

Member
Nov 17, 2012
9,727
Grimor said:
I don't really consider the gas light low, that's just the reminder to get gas (still gallons of gas in the tank). Low would be where you're wondering if you'll make it the 4 blocks to the gas station and which side of E really means empty.

E means empty I believe. Haven't found out how low it will go but I've had it dipped well below E mark, needle width or two below.
Shoot I'll push it four blocks. I'm more worried about having a range of 40some miles when the sign I just passed said "next exit/gas 62miles". That's when you roll the windows up :yes:

I find the gas tank like the water glass. Is it full or empty and by how much? Even with four gallons at 21gal tank you're at 19% capacity. When is it considered "low"? (rhetorical)
 

SEMIJim

Original poster
Member
Apr 13, 2013
116
DDonnie said:
someone changed the name of this thread... LoL.
I don't think so...
confused.gif


Jim
 

SEMIJim

Original poster
Member
Apr 13, 2013
116
Okay, so here's what I experienced...

Yesterday morning, after I parked at work (and asked this question), the fuel gauge needle was reading just shy of right over the "E" hash. IOW: About a hair showing on the low side of the hash mark.

I set off to drive home (17 mi.). I started to become concerned, because it dropped only to the point it wasn't quite fully on the "E" hash (IOW: Just a hair showing on the top side of the hash mark), and stopped there.

Then, just when I went into reverse to back up my driveway, the amber warning light came on and the truck chimed at me. I made a note of the milage: 341.7.

Stopped at my normal gas station on the way into work, this morning. Put 20.867 gallons in at 349.8 miles.

Gas mileage over that tank-full was 16.8 MPG (rounded up). Based on that I used about 1/2 ga. from the time the light came on, until I filled up. So the light came on with approximately 1.6 ga. remaining.

So now I know :smile:

Jim
 

ScarabEpic22

Member
Nov 20, 2011
728
CaptainXL said:
Then don't mention how much gas costs. lol. It makes me sick. You bought an expensive car. And have a tune which uses more expensive gas. So WTH? Looks like you can afford the gas.

Paying for 93 octane is what? $200 more a year? For your car it's worth it.

BTW, I have read that people with corvettes straight from the factory run 87 in their LS2's and they have no knocking.

Id argue it is worth it on my 02 I6 (yes I drove an I6 for 4 years believe it or not) as well. Smoother power delivery, etc (read my previous post). I know gas costs a lot, but the price difference between 87 and 91-93 has stayed the same throughout the whole gas price raise (20-25 cents a gal where I live).

Im going to call BS on a Vette not knocking on 87 octane, I have yet to see a vehicle GM has recommended 91+ for that doesnt knock on 87. Heck all of the Cruze/Sonic 1.4L guys (that GM recommends 87 in) get 3-8* of knock with the factory tune running 91+. Similar to the I6, the best thing to do is run less timing and get rid of the knock. Makes for smoother power delivery and ends up making more power overall.

Do what you want, it's your truck at the end of the day. Im just sharing my knowledge of 7+ years of datalogging an I6 and watching what happens with a stock tune and 87. Honestly ever I6 should get an 87 tune, they knock so much from the factory it's despicable GM let the cal roll out the door as is with the aggressive spark timing.


The Low Fuel light came on in my SS yesterday right as I pulled into the gas station, put 18.87 gal of gas in it (22 gal tank).
 

MDBT

Member
Jan 26, 2012
223
I loaned mine to a relative last weekend so they could have more space to haul things to a softball tournament. I got it back on WALK, which is what I call it when you've passed the low fuel light, passed the beginning of the little red section and have buried the needle all the way past the last little red mark designed to indicate Empty. I made it another 7 miles into town without the warning spits and sputters.

I expect 25 miles of highway and 20 miles of city driving when the orange light comes on and the DIC warns of low fuel. This strategy has never let me down. In practice the range is around 40-50 miles though I've never had the courage to push that far and prefer to fill up once the tank reaches 1/8th-1/4 if on highway road trips where gas stations are plentiful or no lower than 1/2 tank all other times.

For those of you who might like to find out, simply carry a small gas can with you on the day you're going to try it. Worst case scenario you take a little life out of the fuel pump.
 

Shdwdrgn

Member
Dec 4, 2011
568
My warning light always comes on when I hit 39 miles remaining. I guess around 3 gallons sounds about right, because I've never had to put more than about 19.5 gallons in my tank.
 

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