Poor milage and CEL issues

Srytrucker · **Posted:** Wed Dec 12, 2012 1:58 am

hi i recently got myself a CRD liberty 06 with 161k KMs or 100K miles so i have ordered the parts and will get the timing belt replaced this Thursday. So far my mileage is very poor and as such i am inviting feedback on that, with winter fuel and pacific north west rain at 45 degree temp i got 231miles (interstate 5) out of 13 gallons so 17.7 , i did not clean the sensor and have taken pictures of air filter so advice me next course of action.
Second issue bamboozling me is the CEL light it has a mind of its own it shows up and then vanishes a buddy tried to get the codes by his reader nothing showed up. PO had at one point taken it to stealer in the summer and the stealer fished these codes P0670, P0201 and P0299., but nothing was done as stealer wanted 842 bucks plus taxes to replace EGR.
After TB service i intend to clean MAF or MaP sensor and put new air filter that should take care of MPG till i can shell out GDE eco tune and regarding EGR i am clueless as a coupe of shops have tried cleaning the gunk and the codes but no dice so far.
CEL on

CEL gone

Air filter

Is it time to replace? i wanted to hold on till next week and get a K&N i guess i have to do it sooner than later.

ATXKJ · **Posted:** Wed Dec 12, 2012 4:24 pm

K&N's are very bad if you want to keep the engine.

They let in more air and more dirt.

CATCRD · **Posted:** Wed Dec 12, 2012 9:37 pm

A dirty air filter can cost mileage, but I wouldn't us a K&N either. Any filter you can see daylight through is not going in my engine bay.

Also, is that your normal operating temperature when driving? Looks like your thermostat is opening too early which can cost mileage because the viscous heater will run almost continuously.

Srytrucker · **Posted:** Wed Dec 12, 2012 10:37 pm

This was the normal temperature in the pictures after driving for couple of blocks to run errands, I have not seen the needle go any higher on freeway runs either.
Now do you think filter needs to be replaced and if so which one ? How about Wix? thanks for your inputs.

WolverineFW · **Posted:** Thu Dec 13, 2012 1:52 am

As was mentioned earlier, your thermostat is bad based on your pic and description. Lots of people use the Wix (Napa) filter.

TJ2 · **Posted:** Thu Dec 13, 2012 1:41 pm

WolverineFW wrote:

As was mentioned earlier, your thermostat is bad based on your pic and description. Lots of people use the Wix (Napa) filter.

The FSM says running too cool will make the 3.7 gasser sludge up. Don't know why the CRD would be any different.

papaindigo · **Posted:** Thu Dec 13, 2012 1:47 pm

From personal experience with failed by opening too early OEM tstat with the temp gauge sitting just slightly higher in 30-50F weather I lost right about 10% in mpg. That dirty filter probably isn't helping either just spring for a standard Wix or NAPA paper filter.

MRausch82 · **Posted:** Thu Dec 13, 2012 7:50 pm

As others have already said, it is running way too cool, and that will rob the mileage for the previously mentioned reasons. Either replace the tstat or put an inline tstat. As for air filters, a good one, such as a Napa Gold (Wix) would be good. I have used Purolator, Fram (their air filters are alright, but I stay away from their oil filters), and Napa Gold. I prefer the Napa Gold air filters myself.

PermanentGrin · **Posted:** Thu Dec 13, 2012 11:11 pm

IIRC a replacement (Italian) t-stat runs about $140 but it's definitely worth replacing. I could run 30 miles and it would never warm up in cold weather until replacing the t-stat. Had them do a full diagnostic to be sure, though.

Srytrucker · **Posted:** Fri Dec 14, 2012 1:33 am

yup it was the thermostat as pointed by all got that replaced along with timing belt and water pump. New wix air filter is also installed.

Dano52 · **Posted:** Fri Dec 14, 2012 9:31 am

WolverineFW wrote:

As was mentioned earlier, your thermostat is bad based on your pic and description. Lots of people use the Wix (Napa) filter.

I always heard that KN was the way to go....and specific reasons why not?

06 CRD
Frankenlift Premium II
JBA uppers
Samco
245/75s

Srytrucker · **Posted:** Fri Dec 14, 2012 3:55 pm

Not recommended by the tech or the peeps at this forum.

Dano52 · **Posted:** Fri Dec 14, 2012 8:29 pm

Thanks....will go napa this weekend. Mine came with the k&n already installed.

06 CRD
Frankenlift Premium II
JBA uppers
Samco
245/75s

ATXKJ · **Posted:** Sat Dec 15, 2012 10:34 pm

This has been posted before but tends to get lost

http://www.dieselbombers.com/chevrolet-gmc-diesel-tech-articles/16611-duramax-air-filter-testing.html#post214366

Srytrucker · **Posted:** Wed Dec 19, 2012 8:21 pm

So i had the oil changed fuel filter replaced and a new air filter from wix yet today in snowy 40F it returned me a mileage of 15MPG ( 260 km or 160 miles and it sipped 11 gallons of diesel ). So my thoughts are is this normal for this rig in snow conditions or i have a cause for concern.

jlgail4309 · **Posted:** Thu Dec 20, 2012 12:04 am

http://colorado4wheel.com/images/libby/enginebay3.jpg need to clean
did u get cel read that would help. i have seen as high as 25 as low as 12 pulling a travel trailer in a head wind. So 15 in town not so bad if you have a heavy right foot.

Big Montana · **Posted:** Thu Dec 20, 2012 6:45 am

I get 22-24 MPG in Michigan with winter diesel, and I have 10 mile trips to work and back twice a day. I get the Jeep warm for about the last half of my trip. I have the GDE Eco tune though. I guess 15 MPG is ok, and if you're at 100k miles without ever having the EGR deactivated, I suspect that your Jeep isn't breathing very well by now.

Poor milage and CEL issues

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