My Diesel Mileage Sucks

[LeodaJeep]

If I baby my 3.0D, on the Highway I average less than 23.9 and around town around 18: Stock 33" diameter tires too with 3.73 gears. One of the reasons I traded my 2.0 turbo Wrangler was I thought the mileage would be way better than the 2.0 average I was getting. I do not have a heavy foot either; at 4500 miles I'm still holding out hope for the 10K break-in. As much as I love the Diesel in every other way (except for the price of the oil filter), if I had it to do over again, I would still be in my 2.0...and I really hate to be saying that. One of my selling points to my wife of trading in a 1 year old Wrangler was that the mileage was going to be so much better. I have been honest with her and cross my fingers about the possibility of the break-in boost in MPG. How is everyone else's mileage going? Do you think there is something wrong with mine?

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[BuffaloBill]

Those mpg numbers do seem low. Your stock axle ratio would be 3.73. What are your highway speeds? What is your typical trip length?

Mine‘s a Rubicon, stock tires are 33”. 60mph was yielding upper 20S with stock tires. Running 315/70-17 and stock gears was averaging 26mpg combined highway/city. I just recently changed gears to 4.10 so don’t have a lot of mpg data yet, but it seems about the same so far.

Back in 2014 there were some Ram Ecodiesels that gave significantly less mpg than most. One cause I read about was a defective differential pressure sensor used to measure the DPF loading. It was calling for regens more often than normal, driving the average mpg down.

 

[D90John]

I have a 2020 JLUR diesel. It currently has 12,500 on the clock. Just got back from a trip from Oregon to Death Valley, CA and back. 2200 miles. I was towing a 1500 pound low profile trailer with RTT. We averaged around 21mpg. I felt very happy with that. Around home we get 22-24 max. Still much better than the 3.6 in my opinion.

 

[rcliff1]

I'm in Texas where most hwy speed limits are 70-75 (a few 85), I'm getting 24 mpg at 75 on long trips. I'm pretty happy about that.

 

[Ruby Mike]

I just filled up the jeep. I have 18k miles on it and have 315 Cooper STT pros. I drove 230 miles on 9 gallons of diesel or 25.5 mpg. I am very happy with the diesel.

 

[SCOverlander]

2021 diesel jl all stock. Coming from Idaho to California after the purchase 28-29 mpg. 22 around town. After the winch and stubble bumper, I think those numbers have dropped a little. I’ve been running the tire pressure at 37 all around. (Might be a little high)
Not sure why your mpg is so low. Curious as well.

 

[BJACK]

I don't have many miles on my diesel, mostly in town and I've had a heavy foot(enjoying the torque) however I'm getting 22mpg average. My 3.6 Rubicon gets 18 average.

 

[rickinAZ]

I make short hops only, have 35s, and average 19mpg consistently. I also have a Pedal Commander. However, I had to make a 45 minute highway trip for a COVID shot and I averaged 27mpg for the trip. So...the economy is there; just not exploited by my usual driving. In any case, I bought it for the driving enjoyment. That said, I'd equally enjoy a 392, but it would likely only get 10mpg with my driving cycle, and that is a bridge to far for me.

 

[LeodaJeep]

I'll be taking it in for a checkup soon and will post the results. Thanks for the comments.

 

[LeodaJeep]

Finally, on Friday I got a trouble code. P0341 which is the cam sensor. The description says it can affect fuel mileage...go figure. I have an appointment Monday morning.

 

[zouch]

glad to hear you found something that might be the cause; please keep us posted!

stock, i saw 28-29 with mostly open road driving, and mid-20s with more around-town mixed in.
now, after the Mopar 2.5" lift pushed it up about 4" and a bumper and winch but still on stock Mud tires, we saw 25-26 on our last trip with a mixture of mostly hwy at speed, a bunch of in-and-around-town, and even a few dozen miles on steep logging roads in 4-Lo.

Finally, on Friday I got a trouble code. P0341 which is the cam sensor. The description says it can affect fuel mileage...go figure. I have an appointment Monday morning.

 

[LeodaJeep]

Got my suckee mileage JLUD back today. They replaced the cam sensor, the PCU, CMP sensor pins. It had multiple codes for low battery. Repaired nothing, found no cause. Found missing power at the relay to the mirrors. No power to the rear power supply: Codes B10E1, Pulled dash & found short. Found missing circuit between BCM and Power distribution. Well, this goes on and on. I'm hoping they got it right. Also that they didn't mess something else up when they repaired what they found. Hoping I didn't get a lemon!
I'll let you know about the, fingers crossed here...increase in mileage.

 

[LeodaJeep]

Got my suckee mileage JLUD back today. They replaced the cam sensor, the PCU, CMP sensor pins. It had multiple codes for low battery. Repaired nothing, found no cause. Found missing power at the relay to the mirrors. No power to the rear power supply: Codes B10E1, Pulled dash & found short. Found missing circuit between BCM and Power distribution. Well, this goes on and on. I'm hoping they got it right. Also that they didn't mess something else up when they repaired what they found. Hoping I didn't get a lemon!
I'll let you know about the, fingers crossed here...increase in mileage.

Took my first hwy. trip after getting it back from the dealership. I got 27.1 on a California freeway with the cruise set on 70. I was on surface roads for about 20 of 120 miles. Does this seem about right with you all? Around town on startups from a light the gage goes down to about 5mpg until I get it rolling, then as the speed increases and I let up on the pedal, it goes up to about 20. What do you think? Do I have a continuing complaint or did the dealership get it right? Thanks for your opinions.

 

[zouch]

hard to tell on that short of a trip, but sounds pretty typical of what many people are reporting.

 

[gregssstaaa]

Since COVID and working from home I barely drive and if I do, it's short trips mostly on streets. I find my MPG around 20-22. But if I take the freeway on long road trips, I'll get close to or exceeding 30 MPG. I have 4400 miles on the EcoDiesel. I plan on doing the first oil change at 5k. I have heard the MPG goes up after the first oil change too.

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