Declining diesel mileage

[grimmjeeper]

I'm thinking they all come with 4.56s. Mine (diesel) was an anomaly and came with 4.63s due to supply constraints.

I wasn't aware of 4.63s being an option. My understanding is that it jumps from 4.56 to 4.88 with nothing in between. Where did you get the 4.63 number?

Also, I've never seen anything but 3.73s coming from the factory in any diesel regardless of what package it's sold with. So I'm doubly confused.

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[Ratbert]

I wasn't aware of 4.63s being an option. My understanding is that it jumps from 4.56 to 4.88 with nothing in between. Where did you get the 4.63 number?

Also, I've never seen anything but 3.73s coming from the factory in any diesel regardless of what package it's sold with. So I'm doubly confused.

It's an AEV JL370 JLURD. Sorry, I should have made that more clear.

 

[JL Diesel]

What’s the opinion on soot levels vs gas mileage? I don’t have a gauge to see mine but I know I havnt made any long highway trips recently so I’m assuming I havnt had an regen and the mpgs are down a bit right now.

 

[Shibadog]

Where do you live? If you’re in the northern part of the country it’s possible that the diesel your using is now a winter blend which will give you worse mileage.

This, plus speed is not your friend. The aero drag on a Jeep will kill mpg’s at speed,

 

[jonyothan]

although mine is not a diesel. i have a similar issue and i know the cause. for reference mines a jlr 2.0t, i got about 22-23mpg similar to other forum members when it was brand new.. with no mods after driving 5k im down to 17 mpg lol. you said and i quote;
"I admit though I do like to be one of the fastest on the road."
with the gearing of the jeep driving over 65 mph is gonna kill your fuel economy

 

[Ratbert]

although mine is not a diesel. i have a similar issue and i know the cause. for reference mines a jlr 2.0t, i got about 22-23mpg similar to other forum members when it was brand new.. with no mods after driving 5k im down to 17 mpg lol. you said and i quote;
"I admit though I do like to be one of the fastest on the road."
with the gearing of the jeep driving over 65 mph is gonna kill your fuel economy

It's not primarily the gearing. It's the horrible math that gets applied to our aerodynamics as speed through a fluid increases.

 

[jonyothan]

It's not primarily the gearing. It's the horrible math that gets applied to our aerodynamics as speed through a fluid increases.

yeah youre right and the big tires dont help either. but im going to get 35s anyways lol

 

[Ratbert]

yeah youre right and the big tires dont help either. but im going to get 35s anyways lol

It's primarily the weight of those tires. Fortunately diesels don't seem to be as impacted by that as much as other engines. Assuming, of course, that you have appropriate gearing and that you reprogram the computer / transmission to deal with those changes.

 

[Feb14bgirl]

It's primarily the weight of those tires. Fortunately diesels don't seem to be as impacted by that as much as other engines. Assuming, of course, that you have appropriate gearing and that you reprogram the computer / transmission to deal with those changes.

although mine is not a diesel. i have a similar issue and i know the cause. for reference mines a jlr 2.0t, i got about 22-23mpg similar to other forum members when it was brand new.. with no mods after driving 5k im down to 17 mpg lol. you said and i quote;
"I admit though I do like to be one of the fastest on the road."
with the gearing of the jeep driving over 65 mph is gonna kill your fuel economy

I just made it to Missouri from Houston. I made myself drive 65 the whole way or slower. I averaged 22mpg, ALL highway miles. 620 miles. I'll admit though that the temps dropped from leaving Houston at 73 degrees to arriving in Joplin at -6 degrees and around Dallas the wind was wicked. Still, disappointed with the mileage. On the plus side though, my Jeep diesel started right up this morning after sitting outside the -6* temps. My bro-in-law thinks that my diesel fuel around Dallas might have winter additives (?) that could hurt mileage???? I guess I need to stop figuring the mileage and just enjoy it. Merry Christmas everyone.

 

[Ratbert]

I just made it to Missouri from Houston. I made myself drive 65 the whole way or slower. I averaged 22mpg, ALL highway miles. 620 miles. I'll admit though that the temps dropped from leaving Houston at 73 degrees to arriving in Joplin at -6 degrees and around Dallas the wind was wicked. Still, disappointed with the mileage. On the plus side though, my Jeep diesel started right up this morning after sitting outside the -6* temps. My bro-in-law thinks that my diesel fuel around Dallas might have winter additives (?) that could hurt mileage???? I guess I need to stop figuring the mileage and just enjoy it. Merry Christmas everyone.

There's definitely a winter blend of gas. I'm not sure about diesel though.

 

[jonyothan]

Same thing with diesel, actually more additives than gas to prevent fuel from gelling in the tank. i did a long drive in mine this weekend same thing kept below 65mph and was able to get 22mpg. but as soon as i started driving on the highway again it went back to 19ish lol

 

[Feb14bgirl]

Same thing with diesel, actually more additives than gas to prevent fuel from gelling in the tank. i did a long drive in mine this weekend same thing kept below 65mph and was able to get 22mpg. but as soon as i started driving on the highway again it went back to 19ish lol

Well, I've run out of ideas on why the mpg fluctuates so much. The last tank on the way back from Missouri I got 28 mpg. That's my best yet. All Highway but the temps got warmer the closer I got to home. Again, I calculate and try and top off each tank the same for each calculation so hard to believe there might be air bubbles, etc that would cause for such differences. Thank you everyone for your suggestions and letting me know I'm not the loan ranger out there.

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