22mpg average??

dirtmover · **Posted:** Fri Nov 04, 2011 8:39 am

06CRD wrote:

My speedometer reads 4mph FASTER than I actually am going. So wouldn't that make my miles traveled less than odometer is reading, thus resulting in actually lower mpg? If I applied that 1.115 it makes it 24.5mpg which seems more like it, but in reality I'm traveling less miles....which then makes my mileage 19.7. ????

Our CRD lives in a fantasy land where the laws of physics don't apply and distance is not equal to speed X time. In this land gravity is also reversed so fuel naturally flows from the tank up to the engine hence we don't need fuel pump in the tank and a 5mmx5mm bit of plastic is strong enough to hold up a window.

Actually the speedo and odo are driven by different sensors which both have bad calibration. With stock setup the speedo typically reads 10% high while the odo is typically 5% low so for every 100 miles the odo registers you actually travel 105 miles. Adjust your calculated mpg up accordingly.

Joe Romas · **Posted:** Fri Nov 04, 2011 12:39 pm

I think the errors are on purpose :ROTFL:

I've owned many VW's and they all have over stated the speed I was going. I think they are required by law to not report less then actual speed :dizzy:

Honda made some cars that the odometer over stated miles traveled and ended up extending warranties because of it.

So my theory is they are covering their behinds :BANANA:

DieselJeepLuvr · **Posted:** Fri Nov 04, 2011 11:08 pm

Joe Romas wrote:

So my theory is they are covering their behinds :BANANA:

Now that is some truth worth chewing on!

Jeger · **Posted:** Sat Nov 05, 2011 12:01 am

mikey1273 wrote:

Jeger wrote:

Pretty basic, but don't forget tire pressure. I run mine at 40 psi.

40 psi don't that make it a rough ride? I keep mine at at 34 and that's higher than the door sticker.

I prefer words like more firm, stable, improved handling,etc.

I would not call it harsh our rough. It is my wifes daily driver, tires are load range D and she does not complain. Tires wear very even, been running this pressure since we got it home brand new. (180K now)

Do be aware of your tires maximum pressure. Mine are like 80 or 90 pounds but some max at much less. As long as you aren't going over max, 40 lbs is a good pressure for how heavy our little beasties are.

logom · **Joined:** Mon Apr 05, 2010 1:44 am **Posts:** 22

With stock tires my speedo was 4mph off. With 245/75/16's it is only 1mph off. I can get 32mpg only highway at 65. Tires aired up to the max, GDE eco tune, and royal purple synthetic diff fluids. The synthetic diff fluids seemed to give me about 1mpg more. City driving absolutely kills my mileage. Only city driving turns out to be about 22mpg.

CATCRD · **Posted:** Sat Nov 05, 2011 9:54 pm

06CRD wrote:

My speedometer reads 4mph FASTER than I actually am going. So wouldn't that make my miles traveled less than odometer is reading, thus resulting in actually lower mpg? If I applied that 1.115 it makes it 24.5mpg which seems more like it, but in reality I'm traveling less miles....which then makes my mileage 19.7. ????

Your speedo can be high and your odo be low at the same time. They aren't always wrong by the same amount or same direction. Use a GPS trip meter and your jeep trip meter to compare miles on your next long trip.

Rixram · **Posted:** Sun Nov 06, 2011 11:29 am

mikey1273 wrote:

Jeger wrote:

Pretty basic, but don't forget tire pressure. I run mine at 40 psi.

40 psi don't that make it a rough ride? I keep mine at at 34 and that's higher than the door sticker.

My take on that is that Jeep didn't make the tires. The tire manufacturer did. Tires state max pressure on the side, and I keep mine 1-2 below that.

My kidneys can handle being a little shaken, not stirred, especially if it robs those OPEC bass-turds of some money.

Oh, and I make biodiesel for a living now.

danoid · **Posted:** Tue Nov 08, 2011 4:09 pm

mikey1273 wrote:

Jeger wrote:

Pretty basic, but don't forget tire pressure. I run mine at 40 psi.

40 psi don't that make it a rough ride? I keep mine at at 34 and that's higher than the door sticker.

It's a Jeep, rough rides are part of the package. I ride at 60 psi in the summer with load range E summer treads. That's (my estimate) 2 mpg right there.

22 is not bad. The only time I get higher than that is a full tank of freeway driving. Which with a 500 mile range, doesn't happen often. Even then I'll only get 25-26. 'Course I drive bipolar... slow and steady on surface streets, left lane missile on the freeway.

UFO · **Posted:** Tue Nov 08, 2011 8:41 pm

My wife averages 22mpg in our CRD, with typical driving (non)-technique. That's with mostly biodiesel, a SEGR, and tires pumped to 45psi. We've hit 30mpg before, at a steady 65mph on the highway. I'm thinking the GDE Eco-tune might help.

irollgen4s · **Posted:** Tue Nov 08, 2011 11:34 pm

now that i've been tracking mine, mostly town(maybe 30-40% highway speeds) i get about 15-17 town, with impatient driving. GDE tuner comes tomorrow and i'll be setting it up with the hot tune. I'll let you know if it goes up at all after the initial excitement goes away :-)r

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Irollgen4s,

Noticed you do not have listed an aftermarket torque converter in your sig line. You sure you want the HOT tune? It can cause shudder during lock-up at high loads with a stock TC and will eventually require an upgrade within a year or two. Sooner if you drive like me

irollgen4s · **Posted:** Wed Nov 09, 2011 1:39 am

Yeah i've decided to go all out. I very very rarely tow, and if i experience shudder, i'll go with the downshifting technique as a temporary fix. A new torque converter with certainly be installed within the year, One of your tunes was just a priority over it :BANANA:

. Though i tend to say i get on mine a lot, i compare it to how my dad drove it. I never drive above 2500 rpms, usually the max i'll go to is 2300. And based off of my little scan guage, i never go above 50% throttle position either under normal circumstances. So i think i should be okay for a while without a stronger TC.

Expect an email tomorrow around 2 with my CRD's file(assuming the scan tool is delivered before i get home) :JEEPIN:

tonycrd · **Posted:** Wed Nov 09, 2011 5:35 am

I get 20 to 22mpg..and I never floor it...

Pippobug · **Posted:** Wed Nov 09, 2011 6:25 am

tonycrd wrote:

I get 20 to 22mpg..and I never floor it...

x2, best ever has been a 29mpg on a long run on the motorway.

Fil.

jmoomaw · **Posted:** Wed Nov 09, 2011 9:13 am

I just install the inline thermostat and had my tranni rebuilt at 145,000 miles. My first fill up showed 31.5 pg when I was getting 24 mpg before. Now you have me wondering if the speedometer is off. I will have to check it.

I do keep my rpm below 2000 when ever possible. It is slower getting where I am going and it saves quite a bit on fuel. I drive about 35,000 miles a year so it adds up. Any time I save rushing, I loose when the guy I passed 10 miles earlier pulls up beside me at the first stop light looking a lot more relaxed than I am!!!! That is a lesson I have to relearn every so often....

After I check my odometer I will have to repost my Fuelly tag.

mikmaze · **Posted:** Mon Jan 02, 2012 11:28 am

Since I had my egr replaced I have been driving with the maf plugged in so as to not set codes, been getting 21 mpg calculated. This includes a fair amount of idle time warming the car up in the drive way. Hope to be tacking on 3-5 mpg when I swap the ecu for a GDE flashed unit this week.

papaindigo · **Posted:** Mon Jan 02, 2012 12:21 pm

mikmaze - I love my GDE EcoTune (+20% mpg) but do yourself another favor and stop that fair amount of idle time in the driveway to warm the vehicle up. All you are doing is using fuel to go nowhere which doesn't help your mpg. Diesels simply won't warm up much if at all at idle from a cold engine (I tried that with a Dodge Cummins I had semi-stored and at 80F ambient 15 minutes of idle from cold produced no temp gauge movement at all while a 2 mile drive from cold got the gauge 1/2 the way to operating temp). Two options 1) crank it up, flip the tranny into neutral to get circulation going, wait 10 seconds then go, drive at a moderate speed until the temp gauge needle shows life, go whatever speed from there 2) if it's 20-25 F or below consider plugging your block heater in on a timer set for 2-4 hrs before start in which case you can unplug timer, close hood, crank up and drive as you will get engine heat essentially immediately. The block heater costs virtually nothing to run compaired to the fuel you use idling to warm up.

mikmaze · **Posted:** Mon Jan 02, 2012 3:48 pm

yeah I know the idle is killing me, might start using the block heater as the cold weather takes up residence finally, such a weird mild winter so far.

nursecosmo · **Posted:** Mon Jan 02, 2012 11:37 pm

06CRD, Are you lifted? What tires are you running? Something is off if your speedo reads 4MPH faster than actual speed. At what speed is it off by 4 MPH? The only way to accurately know how how far off the odometer is, is to drive 100 miles measured with by GPS and compare it to the odometer.

naturist · **Posted:** Tue Jan 03, 2012 3:47 pm

DieselJeepLuvr wrote:

If it's showing 4 mph faster that means it's also showing more miles on the odo so yes your only getting 19mpg.

You make the assumption that the vehicle's speed sensing and displaying software is related to the distance traveled software. This is not necessarily true. It is typical of speedos to be a touch optimistic (and at least not pessimistic!) on the theory that it will save folks getting speeding tickets, so you will find many cars that read high by a few percent on speed, but not always on distance traveled.

22mpg average??

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