LOST JEEPS :: View topic - Really Lousy MPG

EPA ratings are 19 city/21 combined/23 highway

You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%).

Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still.

A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph.

DarbyWalters wrote:

darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off.

I would be curious to see other persons use their GPS odometers to verify their odometer accuracy.

DarbyWalters wrote:

darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off.

I would be curious to see other persons use their GPS odometers to verify their odometer accuracy.

Sir Sam wrote:

DarbyWalters wrote:

darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off.

I would be curious to see other persons use their GPS odometers to verify their odometer accuracy.

Mine is 6% off with almost 30" tires...by GPS and Mile markers. Speedo still reads a bit fast...64 speedo is 62.4mph GPS

My tires are at 40PSI. I was hoping that would make a difference.

I have a scanner and have checked for code, nothing there. I'll clean the sensor and give the ORM a try before taking it to the dealer.

Author:	mcnaughb [ Mon Nov 26, 2007 4:00 pm ]
Post subject:	Really Lousy MPG
We have 2006 Limited that just turned 10k. We only get about 16 mpg using either b20 or straight #2 (by the EVIC which is pretty close to hand calc). Our best mileage was 21 on a trip from Portland to Boise and back. The car is completely stock except for Goodyear Fortera tires (235x70x16). I have one of the EGR kits, but I was going to wait until after the warranty expired. I'm trying to be realistic with my expectations, but I don't think that 20MPG around town and 25-30MPG fwy is out of line. Could this be an EGR issue? Thanks. -Bruce

Author:	RTStabler51 [ Mon Nov 26, 2007 4:21 pm ]
Post subject:
Without the ORM, I get about 17 intially, then it goes back to the mid18-low19s. With the ORM I get usually upper 20-low 21 in the city. Highway, I haven't really paid attention.... Have you been F37'ed? I saw a good drop when that happened.

Author:	greiswig [ Mon Nov 26, 2007 4:27 pm ]
Post subject:
That sounds pretty low, unless you have your tires aired down to 15psi. I assume the check engine light isn't on? I would assume that if the EGR or AFC valve were really malfunctioning, it would be throwing codes. If you needed to scan them and clear them, I work in Beaverton and could possibly help with that on a lunch hour. The EGR theory would be fairly easy to test: unplug the MAF for awhile to disable the EGR circuit, and ignore the check engine light during the test period. See if your mileage improves. If it doesn't, look for a different culprit.

Author:	nix [ Mon Nov 26, 2007 4:53 pm ]
Post subject:
I got fuel mileage similar to you once. (around 16 MPG avg) I went to a different diesel station on my next fill-up and I returned to my average of around 22 MPG. This is in stop-and-go rush hour traffic. Another thing that might help is cleaning your MAP sensor in your intake manifold. This helped me gain about 2 MPG after I bought my CRD second hand. At around 10k miles it's ready to be cleaned. I don't see any fuel economy difference with the ORM performed on my CRD.

Author:	DarbyWalters [ Mon Nov 26, 2007 5:04 pm ]
Post subject:
EPA ratings are 19 city/21 combined/23 highway You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%). Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still. A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph.

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Author:	mcnaughb [ Mon Nov 26, 2007 5:15 pm ]
Post subject:
My tires are at 40PSI. I was hoping that would make a difference. I have a scanner and have checked for code, nothing there. I'll clean the sensor and give the ORM a try before taking it to the dealer.

Author:	Sir Sam [ Mon Nov 26, 2007 5:17 pm ]
Post subject:
DarbyWalters wrote: EPA ratings are 19 city/21 combined/23 highway You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%). Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still. A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph. darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off. I would be curious to see other persons use their GPS odometers to verify their odometer accuracy.

Author:	Threeweight [ Mon Nov 26, 2007 5:22 pm ]
Post subject:
Where are you buying your B20? I get mine at Jubitz in N. Portland. My 06 Limited has 235/75/16 AT tires, at 38 PSI, and a few other mods. I get around 20-21 MPG in the city and 28 mpg highway. You sound way way low. Check tire pressure, and air filter first. Fuel filter may be another issue. Try unplugging the MAF and see how much the mileage improves... might give you an idea of whether or not it is an EGR problem.

Author:	mcnaughb [ Mon Nov 26, 2007 6:43 pm ]
Post subject:
I'm getting my bio from the SQBioFuels Card Lock on Hunziker in Tigard. They have a B99 and a #2 pump. You mix it yourself in the tank.

Author:	DarbyWalters [ Mon Nov 26, 2007 6:59 pm ]
Post subject:
Sir Sam wrote: DarbyWalters wrote: EPA ratings are 19 city/21 combined/23 highway You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%). Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still. A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph. darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off. I would be curious to see other persons use their GPS odometers to verify their odometer accuracy. Mine is 6% off with almost 30" tires...by GPS and Mile markers. Speedo still reads a bit fast...64 speedo is 62.4mph GPS

Author:	CATCRD [ Mon Nov 26, 2007 7:00 pm ]
Post subject:
Sir Sam wrote: DarbyWalters wrote: EPA ratings are 19 city/21 combined/23 highway You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%). Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still. A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph. darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off. I would be curious to see other persons use their GPS odometers to verify their odometer accuracy. My GPS will show 102 miles for every 100 miles on the odometer.

Author:	Anomious [ Mon Nov 26, 2007 9:30 pm ]
Post subject:
I got around 21 MPG once on a trip last summer. Now I get between 17 and 19 for combined driving. I did the ORM and lost power at higher speeds, 50-70, No codes showing. Think that maybe the air flow thing isn't opening all the way. I do run 37 psi in my revos. LK

Author:	Bill.Barg [ Mon Nov 26, 2007 10:55 pm ]
Post subject:
I found the use of the Power Service "grey bottle" cetane boost worked really well for my B50 or just straight Dino. Cost effective at about $1 per tank (purchased at Walmart). gives me 1.5 more mpg, city. I have identified crappy fuel at particular staitons and avoid them, even if they are 10c cheaper. Also, you might check for a dragging brake. I can push my libby on a flat surface quite easily. This test will also give you a feel for the effect of tire inflation, by the way.

Author:	Sir Sam [ Tue Nov 27, 2007 2:19 am ]
Post subject:
DarbyWalters wrote: Sir Sam wrote: DarbyWalters wrote: EPA ratings are 19 city/21 combined/23 highway You should be able to get those with normal driving. Do make sure your tires are at least 34psi...I run 50psi on some 235/75/16 ATs (this means I must adjust odometer reading by 6%). Remember that the factory Odometer is pessimistic...good to extend your warranty a bit but makes your mileage look worse. You should probably multiply your mpg by 1.04 to adjust for your tires and go from there. Another way to increase your mileage is to put your tranny into NEUTRAL when sitting at a light. When it is left in DRIVE it is still "loading" the torque converter which takes more fuel. On gmctd's computer program mine put out 6 units of fuel when in neutral and 15 units in drive...both sitting still. A few of us are over at http://www.GasSavers.org . There is a "Garage" there where you can track your mileage and get a percentage of over or under EPA Combined. Right now I am at 23.67mpg with almost all city driving. That is 12.7% better than EPA Combined numbers. I can get 30 on flat to rolling terrain on pure highway going about 64mph. darby, using my GPS to track the odometer on the CRD with 245/75 It appears to be less than 2% off. I would be curious to see other persons use their GPS odometers to verify their odometer accuracy. Mine is 6% off with almost 30" tires...by GPS and Mile markers. Speedo still reads a bit fast...64 speedo is 62.4mph GPS Interesting, with the 245/75s (30.5") the speedo/odo is much more accurate.

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Author:	Johnboy [ Tue Nov 27, 2007 12:06 pm ]
Post subject:
Would calibrating the speedo after tires fix the odo? Or would you just need to adjust for error when calculating mileage?

Author:	dgeist [ Tue Nov 27, 2007 12:43 pm ]
Post subject:
mcnaughb wrote: My tires are at 40PSI. I was hoping that would make a difference. I have a scanner and have checked for code, nothing there. I'll clean the sensor and give the ORM a try before taking it to the dealer. Second on the "clean the MAP sensor" comment. Especially before I did the SEGR, every time I changed the oil, I checked that sensor and it was ALWAYS dirty. Each time, cleaning it with MAF cleaner resulted in much less turbo lag and better economy. Also, you can do it without any major parts removal. As for the FCV, you can at least SEE if it's all gunked up with the removal of the engine-side intercooler hose and a strategically placed flashlight. Dan