2006 Jeep Liberty CRD 2.8 liter diesel
 

2006 Jeep Liberty CRD 2.8 liter diesel We are very disappointed in the fuel mileage we get with this Jeep. The best we have got is 25 mpg. Usually we get 21 to 23. it sure seems that this little diesel should get better economy.

We have the Green Eco tune, the lift pump, new fuel filter assembly, New Chrysler crate engine within 20,000 miles, European torque converter,
Weeks Elbow, Cat,

I've posted on several forums. It seems half the owners get 30 mpg and above and the other half get 25 mpg and below. That's where we are. We want to be in the other half.

We drive pretty conservatively and have about zero city driving miles. The nearest town is 7 miles away. The nearest stop light is 15 miles.

Some guys claim to run their's hard and still get 30 mpg plus.

We have had 4 vehicles that got 30 mpg plus - 1981 Datsun 510, 1982 Chevette diesel, 1988 Chevy Spectrum and 1989 Chevy Spectrum - and that is what I was expecting out of this.

The rest of our vehicles are GMT400 6.5 turbo diesels. 98 Suburban, 96 Suburban, 95 2 door Tahoe, 94 K3500 5 speed crew cab

Welcome to Ecomodder jrsavoie! You are in the right place to increase your fuel mileage :thumbup:

Do you have some kind of instrumentation? Being able to see real time data will show any imperfections in your driving. I thought I was a conservative driver until I came here and bought a ScanGauge. Talk about a wake up call!

I would shrug off what others say unless they can back it up with data. Don't let them discourage you.

Since you drive mostly highway, aero mods would be the way to go if you were to mod your Jeep.

How is your drive? Can you provide details?

BTW, I absolutely LOVE your vehicle armada that you have!

Our drives very with very little city driving. Mostly 2 lane country highways and some interstate 57.

Our 98 Suburban got 18 mpg hauling a 26' camper back from Bethlehem, Pennsylvania.
With zero mods.
The K3500 got a steady 18 mpg until I added the rack and side tool boxes. I can not believe the little Jeep can not do better, Especially with the mods I've done already. My next planned mod is an electric fan kit. Should give us about 2 mpg.

What are your speeds when driving?

Electric fans are a good mod for better mileage.

It does not just improve the overall MPG, it also helps to reach the optimum working temperature faster, which is more critical in a Diesel than in a gasser.

Be wary of OBDII tools, especially the ScanGauge. The Chrysler designed CAN bus is very busy, and adding tools into it via the OBDII port often causes the transmission computer to trip out. It can be disconcerting to have shift points disabled while driving.

A 2006 CRD probably does not have the original shift points. They were "upgraded" due to the torque converter being inadequate to handle the low rpm torque of the diesel engine, that could be one contributor to your poorer fuel mileage. I had a 2005 model with the lower shift points and routinely got 30mpg on the highway, if I kept speed at 65mph or below, making sure the tranny was locked in top gear - for the old shift points this happens at 57mph, later flashed up to 61mph.

Make sure you have a clean air filter. The CRD has a very small filter, same size as the 3.7 gasser and should be changed often, sometimes less than 10k mile intervals.

How would I get my shift points changed?

OUr driving speeds range from 30 to about 78 mph. Usually around 55 mph

I think Green Diesel was looking into re-programming the transmission computer, I do not know if they were successful. The only other way is to find an old transmission computer from an un-recalled '05 model.

I trust you frequent the LOST Jeeps CRD forum? LOTS of good technical information there.

http://www.lostjeeps.com/forum/phpBB3/viewforum.php?f=5

Thanks.

Yep, I started at lost as soon as I got this Jeep.

I'm going to have to look into changing the shift points. It shifts into high when the speedometer reads about 63 mph. Our speedometer is about 4 mph fast. We are traveling about 4 mph slower than what the speedometer shows. with 235/70R16 tires. 225/75R16 were original. And were actually taller than the 235/70's

We are about to buy new tires for this thing. Not sure which size to go with for the best fuel economy. Not sure what load range to go with. One guy is running LT load range E tires like I do on the GMT400's.
I was thinking load range C or D tires would be plenty.

I drove a set of 215/85/16 tires. Taller, narrower, fit fine, I don't recall if my mileage was better or not. I did not like how expensive truck tires are and I only got 50k miles out of them, so I went cheaper/better wear at the stock size.

Improved airflow can do miracles in a Diesel.

Indeed, and the contrary holds true as well. I plugged the filter on my CRD twice, to the point where the engine would barely run. And the fuel mileage takes a dive.

Isn't there any larger air filter housing that could be retrofitted to the Liberty? Apart from those externally-mounted heavy-duty filter housings that would increase the drag, obviously.

I am also looking for an upgrade for a cold air intake.

I hate flat panel filters. Is there something I can build or buy that tales a high quality air filter that will both filter and allow air flow?

If you want an element that filters more than bugs and rocks, don't get a K&N. They flow well, but don't filter much dirt.

X2 on that. I'd like to fit the big filter that the 1998 6.5 diesel Suburban uses. I doubt that's a possibility though

Not that I have seen. Must not be enough of these out there to justify anybody making a good aftermarket kit

There is no room to fit a bigger box without removing something else. It's boxed in by the wiper fluid reservoir, the power steering reservoir, and the vacuum controls. I put a V6 airbox on mine as the air flow path is cleaner and not as susceptible to rain water. Unfortunately the filter element is the same, and I think the solution is to simply change it more often.