1jz Sc3---- 10MPG! :(

Prettyazznouka

New Member
Oct 17, 2007
75
0
0
NYC
Ok its starting to annoy me that Im putting 20 bucks of gas and I can run through it in a day. Yesterday I put 10 bucks in and thats 3 gallons just to see how long it lasts. By the time i got home it was gone. If i was getting around 20mpg I would have gotten atleast 60 miles out of that. nope! say 30 miles if that much. Whats going on???? Ive even went through half a tank in like 2 days! And i drive like a grandma most of the time.

I have to drive to atlanta for emissions for xmas.... im not gonna go with it running like that!
 

lagged

1991 1JZ
Mar 30, 2005
2,616
0
0
38
new rochelle
first off, you should determine your actual MPG. the way you have figured it is pretty inaccurate.

you can fill up your tank all the way, IIRC the tank is 18 1/2 gallons.

set your trip meter to zero and run the car to the half way mark. so you can estimate that you have burned 9 and a quarter gallons of gas.

now you can make an approximation of your mileage.

now if youre mileage is completely out of whack the first thing to do would be to check codes and do a complete tune up.

aside from that, the JZ experts will have to chime in to help you further.
 

pimptrizkit

thread killer
Dec 22, 2005
1,572
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vancouver Wa
^^ why estimate? Fill up your tank, drive it till your half way down and go fill it up completely full again. Find out the amount of mileage by the amount of gallons of gas you put in the second time.
 

lagged

1991 1JZ
Mar 30, 2005
2,616
0
0
38
new rochelle
pimptrizkit said:
^^ why estimate? Fill up your tank, drive it till your half way down and go fill it up completely full again. Find out the amount of mileage by the amount of gallons of gas you put in the second time.

good call. doh! :icon_bigg
 

Slow_Sc3

I beat bikes dude
Apr 2, 2005
401
0
0
Maryland
something is wrong then, my 1.5jz sc300 gets better mpg.

try staying out of boost i know its hard but you will get better mpg

its mostly because of those little turbos and the full boost at 2000 rpm

also the filter that your map sensor vac line is plugged into on the side of the intake manifold could be clogged try swapping the map sensor vac line for the vac line port under it that has helped a few people out before.
 

masterchief819

New Member
Apr 4, 2006
258
0
0
us
With the 1j, it all depends on how you drive it. Back when I first got it, I was so addicted to flooring it and driving like a maniac, I got like 13-14mpg one time. Now that I've had it for a while and drive shifting at 2500rpm like 90% of the time, I get 22mpg consistently driving only city.
 

Prettyazznouka

New Member
Oct 17, 2007
75
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0
NYC
Well ive had the car running since may so im pretty used to it now. Not really boosting like everytime i drive it. I usually run it to about 3000rpm b4 i shift though. Maybe i should cut it down? I changed the spark plugs back in july so i dont think it should be a problem? I was thinking of changing the 02 sensor to see what it does.

As far as filling up the car..... thats gonna be like almost 60-70 bucks..... yea it hurts to fill the car up. (hmmm a jetta tdi sounds so good right about now lol)
 

Tim

regular member
Oct 16, 2006
272
0
0
CA
you don't have a wideband, do you? Then you can see how rich your car is running.
 

Slow_Sc3

I beat bikes dude
Apr 2, 2005
401
0
0
Maryland
Prettyazznouka said:
no, no wideband. just stock 1jz no mods what so ever.


no need for a wide band just stop driving like a mad man and take its easy with the gas pedal.

nuff said thread close /

there is no way in hell your stock 370cc injectors are going to give you poor mpg its your driving.
 

Rich

tunin' tha beast
Jun 2, 2007
319
0
0
the netherlands
could be a bad O2 sensor

and btw, over here it costs about $150 to fill up the tank, maybe that soothes your wallet pain a little ;)
 

Bigzavs

86.5 1JZ Single Turbo
Apr 21, 2005
2,267
0
0
39
Arlington, TX
ya stay off the throttle, check your O2 sensor like rich said, check for any vacuum leaks

you should get much better mpg than that, with 550cc's i was getting 25-26mpg on my single setup. i was also shifting at about 2500rpms
 

Prettyazznouka

New Member
Oct 17, 2007
75
0
0
NYC
Ill just change the o2 sensor.... start shifting at 2500. I dont have any vacuum leaks it reads -20 on the gauge. I had a leak but my friend fixed that for me. Anything else to look out for?
 

supraracer49

3rd Gen Life
Nov 20, 2006
333
0
0
WNC
If I shift at 1800 I get very good gas mileage on mine. stock 1j's don't get very good gas milage I can never keep mine from trying to boost and its BPU:evil2:
 

OneJoeZee

Retired Post Whore
Mar 30, 2005
5,721
0
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38
aboard the Argama
Gas mileage? eh, who cares? :) If I'm getting good gas mileage, that means I'm not having fun. And if I'm not having fun, I might as well sell the car. :)

I don't remember the last time I shifted under 3500.
 

Prettyazznouka

New Member
Oct 17, 2007
75
0
0
NYC
Its my daily driver.... its not fun putting gas in the car every day. im a poor college student... wait im graduating hahah but im still poor. Which o2 sensor to use? 7mgte 91-92?
 

lagged

1991 1JZ
Mar 30, 2005
2,616
0
0
38
new rochelle
Prettyazznouka said:
As far as filling up the car..... thats gonna be like almost 60-70 bucks..... )

where the FUCK are you getting gas? it costs me ~40 to fill it up with 93 here.

did you check error codes? do a COMPLETE tune up:

spark plugs
check belts/belt tension
replace all fluids

AND if needed, replace your o2 sensor.
 

Prettyazznouka

New Member
Oct 17, 2007
75
0
0
NYC
Ok i just drove the car 22 miles... shifted at 1800 about 85% of the time, tried to keep from boosting and the gas needle didnt move at all. So far so good... ill see how long it will take for me to burn 20 bucks of gas. I was drivin ultra conservative... id have to get use to it. But hopefully I can drive kinda normal after I change the o2, front end work, and alignment. Maybe all the stress on the car is contributing to the loss.
 

Quin

Trans killer
Dec 5, 2006
1,989
0
36
33
Columbus, IN
I got about 6MPG in my Supra for the first week I had it, don't feel too bad =]

I was going to add some stuff but it's all already been said, just go do it.