POOR GAS MILAGE

[wadebishop]

I'm getting trashy gas milage!!!

 

Any ideas how to get that better??

 

[I've replaced injectors]

[Pete M]

how bad?

[wadebishop]

seems like 10mpg in the city --- feel like i go through a lot of gas!

 

[MiNi Beast]

How many miles do you get per full up?

All sorts of things contribute to poor gas mileage. Box jeep design, cad, fuel filter, air filter, dirty intake, carbon buildup in the engine, weak spark, oversized tires, gearing, poor fluids, lead foot, bad timing and thats what i got off top of my head. Start there and keep us updated on your progress. 

[87MJTIM]

Year? Eng? Trans? 2x or 4x?

[wadebishop]

sorry...1988, i6, 4x4 [not sure the trans?]

 

[wadebishop]

2 hours ago, MiNi Beast said:

How many miles do you get per full up?

All sorts of things contribute to poor gas mileage. Box jeep design, cad, fuel filter, air filter, dirty intake, carbon buildup in the engine, weak spark, oversized tires, gearing, poor fluids, lead foot, bad timing and thats what i got off top of my head. Start there and keep us updated on your progress. 

THX! I get about 180 miles to a tank [16gal]

Standard tires

Good Fluids 

I'll have to check the rest! 

 

[MiNi Beast]

Yeah you should get atleast 300. Ummm, check things out and we'll go from there. 

[MiNi Beast]

Would that be automatic or manual? Auto will be aw-4 and manual could be the puke-5 or ax-15. 

[87MJTIM]

Possibly stuck in open loop with long term fuel trims very high.  You will need to perform more tests to understand these engines and fix the problem.

 

Do you have a Nickintimedesign REM yet?  If not, it is well worth getting.

 

Also, download the electrical and Renix fuel system manuals from the DIY section.

[gogmorgo]

cruiser54.com if you haven't been there already. Make sure your ignition components are all in good shape, spark plugs, wires, cap and rotor. If you don't know how old they are best to go ahead and change them. There's another recent thread about fuel economy that's worth a skim. 

 

[wadebishop]

Thx everyone for the help!  I’ll get started (although it’s -21 today🥶🥶🥶)

 

I’ll let you know

[gogmorgo]

If you're leaving it idling for extended periods due to the cold, or running in 4x4 a bunch, that'll tank your MPG pretty hard too. 10 is still pretty low, but in winter if I was getting 14mpg out of my 4.0 MJ I was smiling. The engine is coming up to temp, yes?

[75sv1]

I usually only post my highway mileage. Also, is yours manual or auto? It makes a different of at least +2-3 mpg with a manual. Also, tire size. I'd also see what the tire psi is. They deflate in the cold. I'd say I get 14 mpg in mixed driving and 18 mpg with my 2000 XJ on 31's and an auto. I'd get 23 mpg with my stock '88 MJ and a manual trans. Also, what temps if the engine running at? I do get less MPG in the winter and colder months. 

[Pete M]

plus your foot matters a lot.  my first MJ was only 10 years old at the time I got it and I regularly got ~12 mpg for, um, reasons.    but a long freeway drive would give me around 20 so I didn't much worry about it. 

[EUREKA]

On 1/27/2022 at 7:54 PM, 87MJTIM said:

Possibly stuck in open loop with long term fuel trims very high.  You will need to perform more tests to understand these engines and fix the problem.

 

Do you have a Nickintimedesign REM yet?  If not, it is well worth getting.

 

Also, download the electrical and Renix fuel system manuals from the DIY section.

I can't wait to get one of the clock panel ones.

[87MJTIM]

4 minutes ago, EUREKA said:

I can't wait to get one of the clock panel ones.