Unhappy with MPG - looking for ideas

[aldo98229]

When you initially used the Tazer did you just set it for the spec height of the tire? If so, that is what your biggest issue was all along.

Not quite. I was making two mistakes: (a) over-inflating the 35-inch tires to 36 PSI, and (b) measuring them inaccurately from the floor to the top of the tire (34.5 inches).

After I deflated the tires to 32 PSI, and then re-measured them from the floor to the hub, the new reading came out to 33 inches —significantly less than 34.5.

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[TheRaven]

For clarification, my drop in fuel economy is real, not just imagined by a miscalculated figure from the ECM. The rate at which I’ve been going through tanks of fuel is quite real.

But objectively, how are you measuring that? If your ECM cannot calculate distance traveled properly, that means your ODO and Trip meters are wrong also...so you can't use those to calculate MPGs. You would need an independent way to measure distance...and something like GPS isn't accurate enough to use for MPG calculations.

 

[aldo98229]

But objectively, how are you measuring that? If your ECM cannot calculate distance traveled properly, that means your ODO and Trip meters are wrong also...so you can't use those to calculate MPGs. You would need an independent way to measure distance...and something like GPS isn't accurate enough to use for MPG calculations.

Point taken, but my increased need to stop at the pump does not lie.

BTW, my speedometer came from the factory off by 1.5 MPH. On my 1,000-mile drive from the selling dealer to my home, I checked my speed multiple times against those police radar signs on the side of the road: the factory settings kept overstating my speed by 1.5 MPH.

I suspect my JL was not alone, which means a lot of JL owners are mis-reading their traveling speed, and mis-reporting their odometer readings and fuel consumption.

 

[aldo98229]

5/13/2022 UPDATE:

As some of you know, I’ve been struggling with extremely poor fuel economy numbers since last fall. As the weather got cold, my MPG dropped to 12-13 MPG around town, and 15 MPG on the freeway.

For reference, my 2018 Sahara is a V6, automatic with a dealer-installed Mopar lift and 35-inch ATs.

Regearing

Due to the tall 3.45 gearing and the large tires, my auto wasn’t shifting past 6th gear. So last February I took a 1,000-mile road trip from WA to UT to have the gears swapped to 4.88.

My MPG getting there was a pathetic 12.7!!!

The gear swap went swimmingly and the Jeep regained full use of the 8-speed automatic. I really like how the Jeep drives and feels.

Refueling in UT and WY

More interestingly, though, I noticed my fuel consumption improve significantly the moment I started pumping gasoline in Utah, jumping to 18 MPG on the first tank.

On the way back, with the new gearing, full use of the automatic transmission, and returning to our shitty west coast gasoline blend, I averaged 15.7 MPG. An improvement of 3 MPG.

However, driving around town over the past couple months my average has been going back down: it was 13.7 MPG early this week.

Trying NO ETHANOL gasoline

I found a gas station at a nearby Indian reservation that sells 92 octane gasoline with NO ETHANOL. As an experiment I filled up the tank two days ago: I can cautiously say that my average over the first 50 miles appears to have improved by 3+ MPG to 17; mostly in city driving. If this holds, I should be averaging 18-19 MPG on the freeway. Similar to what I saw driving through UT and WY.

I’d be very happy with that.

Moral of the story

If you are frustrated with your JL’s low MPG figures and are running out of ideas: see if you can find a gas station near you that sells NO ETHANOL gasoline, and give it shot. My bet is you will see a dramatic improvement in your MPG.

 

[MerPinXEss]

Your update made this bump ot the top of the que, after the first 4 pages I went TL:DR and skipped to your most recent update, thanks for summarizing...Here is my 2 cents, which may have been stated in there somewhere. With used car values as high as they are before you swap out tires and lift consider if you can get paid to order yourself a new one. If vro/vana/max will pay you close to MSRP and you keep the easy swap stuff(bumpers,winch...), it might be worth starting over with a Rubi or even something with XR

 

[aldo98229]

Your update made this bump ot the top of the que, after the first 4 pages I went TL:DR and skipped to your most recent update, thanks for summarizing...Here is my 2 cents, which may have been stated in there somewhere. With used car values as high as they are before you swap out tires and lift consider if you can get paid to order yourself a new one. If vro/vana/max will pay you close to MSRP and you keep the easy swap stuff(bumpers,winch...), it might be worth starting over with a Rubi or even something with XR

Thanks. I will be very pleased if my fuel consumption holds at 17-18 MPG on no-ethanol gas.

The gas station that sells no-ethanol gas is 18 miles away. But I can justify driving the 36-mile round trip if I can squeeze an additional 90-100 miles out of each tank on no-ethanol.

Per ordering another JL: I got a sweet deal on this one; paid 22% off MSRP; love the Mopar lift, and the Jeep's been trouble-free.

I’ve been driving Wranglers for 14 years. I had lots of fun in them. But I think I’m getting over them.

I’ll keep enjoying this, especially now that I seem to be getting decent MPG once again. But I think I’m ready for something smaller, nimbler, fun and more efficient next.

 

[Steph1]

Thanks. I will be very pleased if my fuel consumption holds at 17-18 MPG on no-ethanol gas.

The gas station that sells no-ethanol gas is 18 miles away. But I can justify driving the 36-mile round trip if I can squeeze an additional 90-100 miles out of each tank on no-ethanol.

Per ordering another JL: I got a sweet deal on this one; paid 22% off MSRP; love the Mopar lift, and the Jeep's been trouble-free.

I’ve been driving Wranglers for 14 years. I had lots of fun in them. But I think I’m getting over them.

I’ll keep enjoying this, especially now that I seem to be getting decent MPG once again. But I think I’m ready for something smaller, nimbler, fun and more efficient next.

I’m with Aldo regarding trading on another JL.
My 18 Sahara is also now complete build wise. It now turns the 35s as well if not better than it did the stock tires thanks to a regear to 4.56 in my case. It’s been paid for since last year and gas is my only expense. So gas would need to quadruple in price to start looking like a car payment. I see no logic in trading just for the heck of it for something that looks identical inside and out.

So until the next model which should be in 5-6 years this jeep is going to be it.

 

[SFDemo]

That's the farce with ethanol fuel. It doesn't save pollution really, since you burn more for the same result, let alone the petro dollar cost of creating and transporting. Fuel is not infused with ethanol until after it is shipped via pipeline due to the corrosive materials and problems.

 

[The Last Cowboy]

Did you adjust for new gearing using the Tazer?

We should all see a reduction in fuel economy soon with the E15 executive order.

Mine with stock tires is showing an average 20 on the dash. Pretty close hand calculated. The next tires will likely be no bigger than 285s. No need for big mods where I live, especially given the price of fuel.

This Jeep will be with me for many years, as it’s a third vehicle. I will probably buy a motorcycle in the near future. Not for fuel savings, I just miss having one.

 

[aldo98229]

Yes, the shop re-calibrated the Jeep after re-gearing.

 

[aldo98229]

That's the farce with ethanol fuel. It doesn't save pollution really, since you burn more for the same result, let alone the petro dollar cost of creating and transporting. Fuel is not infused with ethanol until after it is shipped via pipeline due to the corrosive materials and problems.

My understanding is that ethanol helps prevent excessive evaporation.

I can see that being of benefit in Los Angeles, where you have millions of cars in a confined space. But I live in a town of 90,000 right up against the Canada border. We are more likely to get Sasquatch farts released into the atmosphere than excessive gasoline evaporation...

 

[58Willys]

Your mpg seems really low. You have Select Trac correct? What position are you running your transfer case in? If you have it in Part Time 4WD, this could suck some mileage I think.

 

[Heimkehr]

This Jeep will be with me for many years, as it’s a third vehicle. I will probably buy a motorcycle in the near future. Not for fuel savings, I just miss having one.

Funny you should mention that. Some years ago, I walked away from convertibles because I decided motorcycles were more fun. More to the point, the budget at the time required that I choose one or the other.

I still have two 'cycles in the garage, but decided to revisit soft tops, via my JLU, just for old time's sake. Being able to choose one or the other now is the best of both worlds.

And give me 5 minutes with a spreadsheet, and I'll diplomatically shoot down any hope of saving money by owning a motorcycle...

 

[roaniecowpony]

When I was younger, I traded in my superbike for an open cockpit super airplane. A Pitts Special. I could hang upside down with the wind in my face in that thing. No saving money with it.

 

[DavidArmen]

I was averaging 14-15mpg in my 2021 JLUR 3.6 eTorque 8Auto fully stock 285/70r17 ko2s.

I am still averaging 14-15mpg with 315/70r17 load c ko2s with 30lb 17x8.5 wheels.

Only change I noticed:
I was averaging 19 highway-only mpg on 285/70r17 ko2s and am now averaging 18 highway-only mpg with the 315/70r17 ko2s and 30lb wheels.

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