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

[1jzsupbra]

I didnt get but about 8 mpg the first week either! I was was alittle scared it would stay like that!

 

[viperkillertt]

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.

Yeah, definately do not trust the fuel gauge. It fluctuates

 

[viperkillertt]

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.

Haha, I bag to differ, I am getting 12mpg without running any boost. I shift very carefully and after 2 months, i am still getting 12 mpg. I also do have a wideband and the car runs at like 12 AFR until warmup and then almost exactly 14.7 when warm. So yeah, i am also in this boat of being baffled. I was completely expecting 20s like everyone else talked aobut. Driving 360 miles on the freeway, i averaged less then 18 mpg. I do have the Blitz ecu, but this super sucks!

 

[viperkillertt]

Alignment, tire pressure, and driving with the windows up or down are also contributing factors.

Kinda wondering where people would be driving with windows down at this time of year. It is 27 outside and snowing

 

[viperkillertt]

Haha, I bag to differ, I am getting 12mpg without running any boost. I shift very carefully and after 2 months, i am still getting 12 mpg. I also do have a wideband and the car runs at like 12 AFR until warmup and then almost exactly 14.7 when warm. So yeah, i am also in this boat of being baffled. I was completely expecting 20s like everyone else talked aobut. Driving 360 miles on the freeway, i averaged less then 18 mpg. I do have the Blitz ecu, but this super sucks!

Big update and hopefully the SC3 can try. I am not sure if you have changed your plugs yet, but i would definately suggest. I just did last week and one of them were basicly broken. It had been bent and had a gap of less then .12. That was what was causing my 11-12mpg and basicly no performance. Good luck, i hope this helps.

 

[Prettyazznouka]

i just changed my plugs in august.... but i did use 110 octane gas at one time. Ima take it out to see if theyre ok.

 

[viperkillertt]

hmm, weird. yeah, check them out. Being that it is a 1j, they really dont take too long to get out. So much nicer then a 7m. How is the power?

 

[drewgo]

Haha, I bag to differ, I am getting 12mpg without running any boost. I shift very carefully and after 2 months, i am still getting 12 mpg. I also do have a wideband and the car runs at like 12 AFR until warmup and then almost exactly 14.7 when warm. So yeah, i am also in this boat of being baffled. I was completely expecting 20s like everyone else talked aobut. Driving 360 miles on the freeway, i averaged less then 18 mpg. I do have the Blitz ecu, but this super sucks!

Try the opposite. Don't shift early go on a little boost. I am averaging over 20mpg and I almost always shift around 3k. when I baby the car it gives less MPG. My conclusion is that the engine runs more effiecient in that range. Meaning that under 2k it consumes more fuel to get the car moving.....
I don't know but if someone can comment on my situation would be very enlightening.

 

[OneJSupra]

Try the opposite. Don't shift early go on a little boost. I am averaging over 20mpg and I almost always shift around 3k. when I baby the car it gives less MPG. My conclusion is that the engine runs more effiecient in that range. Meaning that under 2k it consumes more fuel to get the car moving.....
I don't know but if someone can comment on my situation would be very enlightening.

I used to shift every 3500rpm with poor gas mileage. Then I tried keeping the rpm at 3k for the first 3 gears and the mileage improved quite a bit. I agreed with Drewgo 1J runs more efficient in that range and when you are ready to get more boost that's when i go nuts and shift the next gears to like 4-5k to wake up the twins. Bottom line, it's all up to you how you drive to get the best mileage you are looking for.

 

[gilberjj]

My 86 civic dx gets 40 mpg....... I hope that helps

 

[viperkillertt]

My 86 civic dx gets 40 mpg....... I hope that helps

Thanks for the assistance!

 

[Big Wang Bandit]

don't be a pussy about boosting, I noticed that if I just boosted, and didn't stay in the area about to come out of vac, that the gas milage went up a lot.

 

[viperkillertt]

don't be a pussy about boosting, I noticed that if I just boosted, and didn't stay in the area about to come out of vac, that the gas milage went up a lot.

I have a theory which i am starting to test, if your car is running well, then if you boost about 5lbs consistantly, i think you will get the best fuel mileage.