something is wrong with my MPG

G

Grkstang

Member Plus
#1
#1
So this past weekend i notice my MPG is really low. Yesterday night i filled up my tank to the fullest and 0ed my trip meter. End of Days comes trip meter says 75 miles(60H-10City average speed 60mph) fuel gauge almost half tank:mad:. I used to get 140+ combined highway miles per half tanks. Dont see any leaks . Saprk plugs cables not even 20k miles, Recently new KN CAI- new aND CLEAN .

Now what im thinking it may be the speedometer, Since changing tire size i didnt calibrate it. I TESTED WITH THE GPS AND ITS was ONLY 2.5 MILES OFF AT 60/mph.

Any clues,opinios,hints,ideas will be appreciate it.

PS i was driving like an old lady today to test it:oldman:
 
W

Wicked One

Super Moderator / Member Plus / Formally Wicked Xt
Staff member
NYM Staff
#2
#2
You need to calibrate your Speedo. If you are 2.5miles off that means that you are going further than the speedo is reading, hence the lower trip range.
 
Aetos

Aetos

2010 Thread Jacker
#3
#3
Wicked Xtreme said:
You need to calibrate your Speedo. If you are 2.5miles off that means that you are going further than the speedo is reading, hence the lower trip range.
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I really don't think that's the problem though. At 60 he's 2-3mph off, I highly doubt that would account for that large of a drop(70miles down from 140)

And at lower speeds, the difference isn't as large.
 
Black Dragon

Black Dragon

Well-Known Member
#5
#5
ALSO, by adding the bigger tires and wheels, you lowered mpg. larger rolling resistance, plus the added rotational mass will account for a decent drop in mpg's all by itself.
 
G

Grkstang

Member Plus
#6
#6
to be honest i did 75 miles and it still needs a bit more to go...prob i can do 20-25 more miles which will bring me around 100 miles still way down:mad:
 
G

Grkstang

Member Plus
#7
#7
Black Dragon said:
ALSO, by adding the bigger tires and wheels, you lowered mpg. larger rolling resistance, plus the added rotational mass will account for a decent drop in mpg's all by itself.
Click to expand...

well i knew that but not so big drop:nono: ...anywho ill prob will go this saturday and get my speedometer calibrated abd see the results
 
G

Grkstang

Member Plus
#9
#9
Ok so I think the not so accurate fuel gauge :smash:played also a role here. I did 30 more miles today totaling 108 and still need a bit more to hit half a tank….I think ill be at 118 miles at half a tank . Now lets say I correct t the speedometer I should be close to where I was which make sense since I changed Wheels. Adding to that that these days I always have the AC on …..
 
N

NYstang

Well-Known Member
#13
#13
Its not...


If my gauge is on E, i put in 5 gallons(roughly 1/3 tank), it only goes up to a quarter. I put in 3 gallons when the gauge is at 1/2, it goes to F. only way is to fill up and calculate.


AC kills your MPG, but even with my car i pull down about 19mpg straight city.
 
G

Grkstang

Member Plus
#15
#15
I dont base MPG on the fuel gauge. I Always pump 6.5l of fuel at half a tank to fill up. With half a tank I used to 150-160 miles combined before installing 3.73s. After that it dropped to almost 140 + or -. So after installing the wheels I would have expected at least 130miles. Yesterday I drove for 75 miles and the fuel gauge showed half a tank and I was wondering wth happened. Today when I turned on the car the fuel guage showed above the midway point , so I drove 33 miles to work and it still is a pinch above midpoint... well see ...Saturday ill correct the Speedometer and well see what happens.


 
Baz

Baz

Well-Known Member
#17
#17
Temperature also plays a big deal, we've been hit with some pretty hot days. If your filling up during the day, a lot of that gas is turning into vapor when your pumping. They were looking into having gas stations required to have self adjusting pumps which would be required to calculate how much you pumped was vapor and only charge for the fuel. As always gas stations complained it can't be done, but were proved wrong as Europe has this, so now they are on the too expensive to do excuse.
 
G

Grkstang

Member Plus
#18
#18
NYstang said:
3.73's?

That explains a lot...


RIGHT FOOT RIGHT FOOT RIGHT FOOT!
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LOL alex yea i do have a heavy right foot:D but as i said i was driving like an old man 60-65 trying to test this thing out. It turns out i did 121 miles and i think thats logical having AC blast, a bit of traffic, plus citi driving. Once i calibrate my speedometer ill test it again.

LOL Baz ive heard of that but i doubt its my situation here. More chance is the fuel to vaporize from myh tank due to my heavy right foot then the weather:D
 
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