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Why am I getting about 34 MPG?

This is a discussion on Why am I getting about 34 MPG? within the General Help forums, part of the LSx Technical Help Section category; Well, about a month ago my fuel pump fucked over and left me stranded on the side of the road. ...

  1. #1
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    Why am I getting about 34 MPG?

    Well, about a month ago my fuel pump fucked over and left me stranded on the side of the road. Luckily, it was the roag going to my house and my mom came by as soon as I started to walk home.

    I then had to leave out for work and stay out ot of town for about 3 weeks, and the car was pulled to our parking lot.

    I get home, get the car towed to a mechanic and he puts a fuel pump up and called me about 2 days later with a bill of about $466.

    I take the car home, everything seems fine. The next day, I stop at the same gas station as I was always use, even the same pump. I fill the tank up and re-set my miles. I drive for a few days, and after a little over 150 I went to fill it up at the same pump as I used before. I filled it up, seen how many gallons it took and did the math to see how many miles it was. It was a tad bit over 34.

    I tried it again soon after and got about 35. I usually got about 22 before I had to get the fuel pump put in. Is it just something the fuel pump does and it will go away or what gives? It's a v8 z28...and I'm really confused.

    Oh, and I know how to do math. It's miles/gallons.

  2. #2
    Senior Member jrc1122's Avatar
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    If you aren't losing any performance (power wise) then I would call it a blessing.

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    Quote Originally Posted by jrc1122 View Post
    If you aren't losing any performance (power wise) then I would call it a blessing.
    No, it drives just fine. After I got it home from the shop I had to instanly take it out for a spin.

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    Veteran 0rion's Avatar
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    What kind of grades did you get in math when you were in school? That does seem to be kind of excessive mileage wise. Is that combined, mostly highway, or mostly around town? Did you fill it to the same point each time? Such as did you fill it all the way until the pump kicked if off both times? Any chance you put a little extra in the fill neck the first time but not the second time although you would've had to screw the numbers up twice so I have no idea why you would be getting that kinda mileage.

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    with a LS1 2MuchFun's Avatar
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    driving 35 mph in 6th gear all the time and no stop and goes?

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    Senior Member INMY01TA's Avatar
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    I think the guy that put in your fuel pump must have inflated your tires to about 45lbs. I'm the original owner of my car and even new/bone stock it never came anywhere near that.

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    Just another Joe Eagle's Avatar
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    I'm with Orion, I think your math is off.

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    LS1 or bust b.lee's Avatar
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    Quote Originally Posted by jrc1122 View Post
    If you aren't losing any performance (power wise) then I would call it a blessing.
    amen that.
    I got 28mpg before in my old ls1.
    34 would be awesome.
    make sure your topping the tank off each time and check your math.
    I'd think anyone can do 300 divided by 15, or whatever the situation is just use a calculator.

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    Quote Originally Posted by b.lee View Post
    amen that.
    I got 28mpg before in my old ls1.
    34 would be awesome.
    make sure your topping the tank off each time and check your math.
    I'd think anyone can do 300 divided by 15, or whatever the situation is just use a calculator.
    It wasn't my math. I'm also not blind...I seen how many miles I drove after I re-set it after filling up the tank and I clearly seen how many gallons it wasn.

    It was filled as close as possible. Both times, I let it go until the exact same pump stopped fueling itself.

    The part that made me wonder the most was...the fact that it wasn't highway at all..but there were only about 10 stop lights the whole time of driving then.

    Also, no...6th gear was never hit, I hardly even needed 5th on those roads.

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    also... dont forget to consider all the fuel in the fuel lines, etc. driving ur car to empty, doesnt actually mean ur OUT of gas.
    (not insulting ur intelligence, tho. just in case u didnt think about that)

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    Member 98ls1blackbird's Avatar
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    I wanna know the name of that garage. Hahahaha. I have a nephew with a 1999 M6 vette and he claimed 42 mpg on a trip to Chicago, all highway. I guess anything is possible.

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    Impounded
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    ha ha ha,i bean dumping a few gals of gas in yyer tank every night.Next week i'm gonna start taking a few gals out every night and you'll think yer gitin 10 mpg!!!!!!!!!!!!!!!!

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    I usually only do stop and go driving and since my cam install i've only been getting 13 mpg, its really starting to get expensive.

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    I'd almost think your trip odometer is messed up and registering more miles than you really did. 34 sounds to good to be true if it wasn't all highway or very low rpms.

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    Quote Originally Posted by Rivi View Post
    ha ha ha,i bean dumping a few gals of gas in yyer tank every night.Next week i'm gonna start taking a few gals out every night and you'll think yer gitin 10 mpg!!!!!!!!!!!!!!!!

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    JEB
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    Quote Originally Posted by xinthenight View Post
    It wasn't my math. I'm also not blind...I seen how many miles I drove after I re-set it after filling up the tank and I clearly seen how many gallons it wasn.

    It was filled as close as possible. Both times, I let it go until the exact same pump stopped fueling itself.

    The part that made me wonder the most was...the fact that it wasn't highway at all..but there were only about 10 stop lights the whole time of driving then.

    Also, no...6th gear was never hit, I hardly even needed 5th on those roads.

    I think that you did not get the gas tank full of fuel because of this statement; "It was filled as close as possible. Both times, I let it go until the exact same pump stopped fueling itself." There probably was an air bubble in the tank that stopped it from taking gasoline. Had you shaken the car with the gas cap off the gasoline filler to burp the air out of the gas tank, you probably would have been able to put another gallon or so of fuel in the tank to make it full. I have added as much as 2 1/2 gallons of gasoline to my gas tank after the automatic pump cut off turned off the gasoline flow. This was done by shaking the car which sloches the gasoline around in the tank which burls the air out of the fuel tank. I do that every time I fill my cars gas tank with gasoline. That way, I know that there is no air in my gas tank and that the tank is full of gasoline. That way I can figure my MPG and know that it is correct.
    Last edited by JEB; 07-03-2007 at 10:44 PM.

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    Rodzilla Tha Cavity Filla zero_proto's Avatar
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    I can see how that is possible. Me and a buddy of mine had a competition to see who can get better gas mileage. I hit 31 with a catback and lid. I would go from 1st to 4th and then to 6th. Most of my driving between work and home is freeway. That was with out ever getting on it, once. It was one of the hardest things i ever did.

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    Yeah i've tried several times to shift at between 2000-2500 for the entire tank to see how good of gas mileage i could get and i yet have to accomplish this great feat.
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    Rodzilla Tha Cavity Filla zero_proto's Avatar
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    yeah it is a hard ass thing to do. I tried several times to do it before i actuall succeded. A couple times i would be driving and i would see something i would want to toy with hell i even passed up a couple of races to keep myself going.

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    Well...I did the exact same thing again and filled it up at the exact same pump.

    This time it was like 147 miles driven and it was 8.__ gallons...either way, it was only about 16-17 MPG.


    EDIT: Anyways, what are the best techniques to save gas? I heard they put that stupid skip shift to save it...but when I actually tried it, it seemed like the car was going to die out because the RPM's were so low and I was going about 3k in first and then straight to 4th. Would first to 3rd, then to 5th help? What RPM range is best to drive in while going down the streets/highway?
    Last edited by xinthenight; 07-05-2007 at 01:42 AM.

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