GenVibe - Community for Pontiac Vibe Enthusiasts

anyone else notice that once you hit a 1/4 tank of gas, the gas level seems to fall very very fast? my last tank i got about 290 miles(city and hiway), is that about average for everyone?

My gas guage doesn't start moving until I have about 40 to 50 miles on that tank full. Then it starts falling bellow full and then it is pretty steady from there.

All depends how the gas thank is designed. Some cars has square thank, but most of cars have "V" thank. All depends how the "V" angle is and in what side the "V" is.

Car and Driver or Motor Trend wrote an article about this a few years back. Bacically, the gauge is calibrated to not be accurate. It seem that automakers were under the impression that owners didn't like to see the fuel gauge start to drop right away after filling up (even though the car was using fuel to drive). So the gauges were calibrated to stay at full longer and then drop more quickly than normal. This gave the illusion that the car stayed full longer. So basically your tank is more than half empty when the needle is on 1/2.

ahhh, between Sub-Vibe-R saying the tank is a "v" shape and the info you stated, it makes sense now. as they say down south, "thanks yall!"

Excellent post once again Scott. It makes sense that they would want the consumer to feel that way. I guess it would make some feel like they aren't being cheated when their gas guage doesn't start dropping immediately.

That article answered alot of questions for me. Personally, I want an accurate gauge. I could care less if it started dropping right away. I have a realistic view that understands the fuel level will obviously start to drop right away since I'm using fuel. What good is an inaccurate gauge?

I use my trip odometer to track kms per tank... a hold over from riding a motorcycle that doesn't have a fuel gauge. I use the gauge for a quick look but regularly check the odo... if I'm up around 400kms, probably time for a fill-up!The nice thing is the Vibe has two trip meters... one for fuel and one for the drive you're doing... I love this feature!

i can do 230 miles on a small fraction more than half a tank.....thats reading it on the guage. this is my trip to and from college. now...that said, if i take the bike off my roof rack and the roof rack off the vibe then the same trip leaves me with more than half a tank. im very happy with that kind of performance.....especially since i have the heaviest lead foot....i dont like it when people pass me on the highway...i have to be the one doing all the passing....heehee!

Wow, that's really good gas mileage. I have to put in about 10-11 gallons at about 230-240 miles. Usually, I get about 23-25 MPG. That is the best fuel economy of any car I've owned. I reset my trip odometer after every fill-up because I also track my fuel remaining by mileage rather than depending fully on the gauge.I remember reading that same article on the intentional inaccuracy of the fuel gauges a few years ago as well. And most gas tanks aren't "V" shaped, but they are irregularly shaped to fit around the car's other underside components. This irregular shape of the tank and the way the gauge and float are calibrated are what affect the way the fuel gauge reads as fuel is used.

Now come to think of it, 230 miles on half a tank is roughly 38.3 MPG. Either the fuel gauge is really off when it reads 1/2 tank or you've got 2 spark plug wires pulled off. The base Vibe is not rated anywhere close to that kind of mileage. A better determination is to track your fuel useage when you fill up. If you reset your trip odometer and fill up the gas tank as full as it will go, then next time you fill up, fill it all the way up again and take note of how much gas it took. Take how many miles are on the trip odometer and divide it by the number of gallons it took to fill up at the pump. This will be about the most accurate and practical way to measure your fuel economy.

i did try that once....it was about a 50 mile trip i think and i was purposely trying to get the best milage possible so i drafted a truck the entire time on the highway at about 55-60mph and that calculation got me 38.7 mpg...............i about crapped my pants!!.....maybe i had a tailwind??????

I almost ran out on my last road trip - guage dropped from 1/4 tank to "E" and the warning light came on over a span of about 10 minutes. Caused me to make an emergency fuel stop because i never ran it that low before and didn't know how much would be left. I stopped in this bad area of Columbus....they had one of those rib bar-b-q oil drums operating in the trashed out vacant lot next to the gas station, and 2" think acrylic on all the windows. The ribs smelled great and i wanted to try to buy some, but felt the best plan was to get out of dodge as fast as possible!

I've got a base 5 speed, no mods, and have been keeping track of my mpg's and have seen a wide variation from tank to tank, between 30.6 to my last tank which was 39.5. I don't believe I actually tweaked 39.5 mpg out of it, because I didn't drive like I was going for max mileage. (left some of those cheap continental tires in a couple of places) I figure there's enough variation in how full I get it before the pump cuts off to account for the extremes. over the last 5500 miles, I've been getting an overall average of 35.8 mpg, almost all highway miles. Pretty close to the EPA rating, so no complaints.I have seen a trend where the mpg is getting better than it was when I first got it, hope that trend continues.

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The other side of that gauge linearity thing is that I don't know if I care whether my tank has 12 gallons in it or 13. The part of the range I'm most interested in is the bottom. It's more important for me to know if I have 2.3 gallons or 1.8 gallons. Since fuel tank senders can be placed at random intervals along the tank to show different levels, it makes sense to me if there are no sensors at the top of the tank to tell me the difference between 12 and 13 gallons. This explaniation irks me since I consider myself an engineer, but I think there's probably some value in the way the gauge is set up - you get the most accuracy when you need it most... BTW, I have been getting really bad mileage during the winter. I had 2-3 tankfuls where I got 240 miles out of 10-11 gallons. Since it's getting warmer though, I'm back up to around 300 miles. I only have two driving modes though - shift at 2500 and stay in 6th, or try to stay between 5000 and 8000 all the time. I really don't do a lot of driving in between.

quote:It is all about psychology. Just like in stores they have the expensive items at eye level and have the cheaper items down at the bottom.In that same car magazine article brought up earlier they talked to some Cadillac engineers who were involved in some of the earlier digital dashboards in the 80's. They were having a problem with owners complaining about the fuel mileage they were getting because the fuel gauge, being a 2 digit readout, dropped from 18 to 17 fairly quickly (18.0 gallon fuel tank, the next lower number is 17.9, only show 17, etc. Well, duh ). Their solution? Remove the 17 from the gauge. Ta-da! No more complaints about fuel milage.Yes, it can be very psychological. However, accurancy is probably more important now-a-days, especially with gas prices they way they are! I'm trying to squeeze out as much milage as possible!

quote:They were having a problem with owners complaining about the fuel mileage they were getting because the fuel gauge, being a 2 digit readout, dropped from 18 to 17 fairly quickly (18.0 gallon fuel tank, the next lower number is 17.9, only show 17, etc. Hmm, it's funny that they weren't able to write up a small bit of code to round the numbers (ie anything between 17.5 & 18.4 => 18).

quote:Hmm, it's funny that they weren't able to write up a small bit of code to round the numbers (ie anything between 17.5 & 18.4 => 18). For sure, it's not complicated at all. My guess is one - some bean counter figured out it would be cheaper to do it the way they did it, and two - too scared of people running out of gas because its showing a bit more than there really is. Hmm is right....

quote:Hmm, it's funny that they weren't able to write up a small bit of code to round the numbers (ie anything between 17.5 & 18.4 => 18). Years ago, I had an Olds Cutlass Supreme with digital gauges... I think whoever wrote the code on that thing screwed up... It had 16 bars on the display, but when I got it down to the last three, (one notch below 1/4) it was outta gas. That's when I learned the value of the trip odometer. I've noticed with most of the cars I've had that once the gauge drops below 1/2, the gauge starts moving pretty quick... Vibe does the same. I have a pretty neat utility on the Palm that keeps track of fuel mileage... You put in the mileage, quantity of fuel purchased, and cost. It calculates each fill-up and give you stats for average economy, average distance and number of days between fills, total amount spent, etc. Even graphs it out for ya. If anyone's interested, http://palmfuellog.sourceforge.net/So far, mileage for the 4700 miles that I have logged into this program, my average is 27.71 MPG. A month ago it was 26, so things are getting better the more I drive it. There were a few tanks in the winter where I only got 20, and some as high as the upper 30's...

I don't know if I just got a good car, but I usually end up with about 32-35mpg on the highway and 29-31 in town. I guess I drive pretty conservatively. It does matter, however, where you get gas.

That's the same program that I use on my palm. I posted about that here somewhere.

Let's expand on that a bit......where does everyone like to purchase their gas from? I usually tend to but from Texaco. Does anyone know of any gas that it "better" than someone else's?Jim

I used to purchase just Texaco and Chevron, because I read an article few years back that only those 2 companies have "fuel cleaner" (Techron) in all of their gas including 87 octane. Mobil had it in 91 + only. and I also recalled that Techron is the best fuel cleaner there is.but I am pretty sure that has changed by now. I believe Arco has it in all the fuel also. anyone knows if other companies have the so called fuel cleaner in all their grades of gasoline.