LX450 Getting 8 miles a gallon!

[Sierras9171]

I’m new to the forum and new to the 80 series. I just bought a 1997 LX450 it has a 3.5 in Dobinson lift with 37’s been re geared with 4:88. It’s currently getting only 8 miles a gallon. Does anyone have some advice on where to start trouble shooting the poor gas mileage?

 

[Road Apple]

8 mph is pretty low. I’m getting 12 mph average with a mix of highway and city on 37’s with 5.29’s.

The list to improve gas mileage is fairly short. Tune-up, replace spark plus, O2 sensors, vacuum lines, and charcoal canister.

Replace fuel pump
“The fuel injection mapping assumes fuel pressure is adequate. Based on air meter and o2 sensor inputs the ECM adjusts fuel injector “on time”(duty cycle). If the fuel pressure is weak, the air meter/o2 reports a lean condition and the on time is increased. The injectors are on longer, and the combustion is less efficient(think piston movement vs injection timing/length)... you could say the ECM was running you fuel injectors at the equivalent of wide open throttle while your foot was at half throttle. Hence the better economy and power.”

Here’s some threads to help.

Fzj80 fuel consumption

Hi guys, I read lots of posts about fuel consumption, and I know this trucks aren’t the most efficient on fuel, didn’t buy it for that. But I believe my data es far below average. Yesterday I filled up my tank. 77 litres. And my Odo read 180 miles. So 77 litres are 20.3 us gallons. Si I am...

forum.ih8mud.com

"Chasing MPG in my 80 series Lx450" How I increased my gas mileage.

Hello all since gas has gone to astronomical prices I thought I could make a game out of it called "Chasing MPG in my 80 series Lx450" How I increased my gas mileage. My 80 for the last 2 years has basically just has been getting me to work & back, it did pull the 25' foot trailer 2 hours South...

forum.ih8mud.com

what is your MPG

So I dont think i have a mechanical problem and I dont have enough information to determine my own mileage. But here it is. I bought my 96 LC-80 with the 4.5L motor seven days ago. The PO had a full tank of fuel in it. Well, the gauge was on the "full" line. And the previous owner warned me that...

forum.ih8mud.com

 

[Sierras9171]

8 mph is pretty low. I’m getting 12 mph average with a mix of highway and city on 37’s with 5.29’s.

The list to improve gas mileage is fairly short. Tune-up, replace spark plus, O2 sensors, vacuum lines, and charcoal canister.

Replace fuel pump
“The fuel injection mapping assumes fuel pressure is adequate. Based on air meter and o2 sensor inputs the ECM adjusts fuel injector “on time”(duty cycle). If the fuel pressure is weak, the air meter/o2 reports a lean condition and the on time is increased. The injectors are on longer, and the combustion is less efficient(think piston movement vs injection timing/length)... you could say the ECM was running you fuel injectors at the equivalent of wide open throttle while your foot was at half throttle. Hence the better economy and power.”

Here’s some threads to help.

Fzj80 fuel consumption

Hi guys, I read lots of posts about fuel consumption, and I know this trucks aren’t the most efficient on fuel, didn’t buy it for that. But I believe my data es far below average. Yesterday I filled up my tank. 77 litres. And my Odo read 180 miles. So 77 litres are 20.3 us gallons. Si I am...

forum.ih8mud.com

"Chasing MPG in my 80 series Lx450" How I increased my gas mileage.

Hello all since gas has gone to astronomical prices I thought I could make a game out of it called "Chasing MPG in my 80 series Lx450" How I increased my gas mileage. My 80 for the last 2 years has basically just has been getting me to work & back, it did pull the 25' foot trailer 2 hours South...

forum.ih8mud.com

what is your MPG

So I dont think i have a mechanical problem and I dont have enough information to determine my own mileage. But here it is. I bought my 96 LC-80 with the 4.5L motor seven days ago. The PO had a full tank of fuel in it. Well, the gauge was on the "full" line. And the previous owner warned me that...

forum.ih8mud.com

Thanks for the detailed response. Good places to start.

 

[clx16]

Make sure your brakes aren't dragging and you have about 33 to 35 psi in your tires. It makes a difference

 

[CalnSam]

how are you calculating the mpg? is your speedometer accurate (gps verified)?

 

[Augustiron]

Remove the air freshener and slide a Prius underneath it.