Poor fuel economy

pjigar · **Posted:** Fri Aug 21, 2015 10:45 am

I was getting 22MPH highway fuel economy when I bought used 2006 CRD.

I did lot of fixes to my Libby in past couple of weeks: Timing belt, water pump, ARP studs, Rockers, thermostat, new water and air hoses, Weeks 1&2, Provent, etc. I was hoping to get better fuel economy than before but now my mileage dropped to 21MPG.

What should I be checking or improving for better fuel economy? Only thing I have noticed different than before is that I can hear turbo chirp louder than before upon acceleration.

Steevo · **Posted:** Fri Aug 21, 2015 12:12 pm

Following... I have done just about everything you listed and only get more than 25MPG average if I'm on a long haul interstate trip. Otherwise I average about 22.5MPG.

pjigar · **Posted:** Fri Aug 21, 2015 12:32 pm

I forgot to add:
1. I have Yeti mild tune. I am going to go back to stock and report the fuel economy.
2. I also installed OME lift kit from rocky road outfitter. Front and Back.

SargeIndustries · **Posted:** Fri Aug 21, 2015 3:01 pm

Grease your brake caliper pins. I gained 2 MPG when I did this on mine. With a bad head gasket and hanging caliper pins I was getting 22.5. I fixed the head gasket and that brought me up to 24.5-9. Now with caliper pins greased I get 26.5 MPG. Hope this helps.

flash7210 · **Posted:** Fri Aug 21, 2015 6:37 pm

What tires do you have?

Back in november I put on new tires with a more aggressive off road tread.
Since then my MPG has gone from 26 down to 23.

A suspension lift can hurt your MPG.

A ECU tune doesnt always hurt your MPG, but usually the extra power makes folks want to push the accelerator pedal harder.

papaindigo · **Posted:** Fri Aug 21, 2015 7:47 pm

Back to basics. How are you calculating your mpg? EVIC which is known to be wildly inaccurate. Hand calculating using odometer reading which can be off as much as +-5% and still meet standards.

To be sure of you actual mpg ideally obtain a GPS correction for your odometer (do a couple of 25 miles runs on relatively straight and flat roads); pick a station with a relatively recent pump inspection sticker; fill the tank until you have clear (no foam) fuel at the top of the filler neck; drive at least 300 miles or so; return to the same station and fill the tank to the same spot; hand calculate using the GPS correction.

Expected corrected mpg on stock CRD with stock size tires and no particular tune is 18-19 in town (assumes moderate temps, relatively flat, 10 mile one way commute on city streets, average speed ca. 25 max 45) and 24-25 hwy (windows up, with/without AC, relatively flat roads, steady 62mph/1800rpm) but both can be better or worse by a significant amount. GDE EcoTune figures ca. 23-24 in town and 29-33 hwy.

PS is you temp gauge needle almost dead vertical when warmed up. If not your tstat is shot and costing you ca 10% mpg.

pjigar · **Posted:** Sat Aug 22, 2015 3:50 pm

flash7210 wrote:

What tires do you have?

A suspension lift can hurt your MPG.

A ECU tune doesnt always hurt your MPG, but usually the extra power makes folks want to push the accelerator pedal harder.

I have normal street tires, 225 75R16. I am trying to be easy on the paddle and I am going to stock just to compare.

Anyone know how much a lift cost in terms of fuel economy?

pjigar · **Posted:** Sat Aug 22, 2015 3:52 pm

SargeIndustries wrote:

Grease your brake caliper pins. I gained 2 MPG when I did this on mine. With a bad head gasket and hanging caliper pins I was getting 22.5. I fixed the head gasket and that brought me up to 24.5-9. Now with caliper pins greased I get 26.5 MPG. Hope this helps.

I also re-did the front suspension: upper+ control arms+ball joints. So I also greased the caliper bolts when putting it back together. I did not pack the rubber tube.

pjigar · **Posted:** Sat Aug 22, 2015 3:55 pm

papaindigo wrote:

Back to basics. How are you calculating your mpg? EVIC which is known to be wildly inaccurate. Hand calculating using odometer reading which can be off as much as +-5% and still meet standards.

To be sure of you actual mpg ideally obtain a GPS correction for your odometer (do a couple of 25 miles runs on relatively straight and flat roads); pick a station with a relatively recent pump inspection sticker; fill the tank until you have clear (no foam) fuel at the top of the filler neck; drive at least 300 miles or so; return to the same station and fill the tank to the same spot; hand calculate using the GPS correction.

Expected corrected mpg on stock CRD with stock size tires and no particular tune is 18-19 in town (assumes moderate temps, relatively flat, 10 mile one way commute on city streets, average speed ca. 25 max 45) and 24-25 hwy (windows up, with/without AC, relatively flat roads, steady 62mph/1800rpm) but both can be better or worse by a significant amount. GDE EcoTune figures ca. 23-24 in town and 29-33 hwy.

PS is you temp gauge needle almost dead vertical when warmed up. If not your tstat is shot and costing you ca 10% mpg.

I am hand calculating MPG using odometer reading from full tank to full tank. I am assuming GPS to odometer error to stay constant. Next time, I will correlate GPS miles to odometer miles to find out what is my actual MPG!

The coolant temp is 195 F with temp gauge almost dead vertical. The warm is less than 2 minutes as well.

By the way, my highway commute speed ranges from 70 to 80 mph with average of 75 mph.

pjigar · **Posted:** Thu Aug 27, 2015 7:52 pm

I correlated odometer miles with GPS miles. My CRD odometer shows 1 mile for every 1.05 actual GPS miles. I did two laps of 50 miles on highway and both runs showed exact same correlation.

Here are my highway GPS MPG, full tank to full tank, hand calculated, with stock ECU tune, 70 to 80 MPH speed.
20 MPG going against the wind. Dallas to Austin.
26.7 MPG going with the wind. Austin to Dallas.

Next week, I will try the Yeti mild tune and report back. I should note that I installed all new rockers recently. The big difference in MPG (compared to wind direction) tell me that rockers settling might be at play here. I will find out the rocker factor is true or not after the MPG numbers from next week.

lemonade · **Joined:** Sat Aug 01, 2015 9:05 pm **Posts:** 3

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lemonade · **Joined:** Sat Aug 01, 2015 9:05 pm **Posts:** 3

Ok just sent the day with

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Bluemoon · **Posted:** Thu Aug 27, 2015 9:28 pm

Lemonade didn't finish her post.
I am her husband, Geordi spent the day rebuilding the top end of our CRD.
just a few weeks ago we were wondering if it would ever run again, when I found this site and began studying the options we had, we began to have hope for it again.
Geordi came with all the parts and worked his magic on our motor!
now she is not blowing smoke and you better hold on!!
got to come up with a different name for her now, it was " Puff The Magic Dragon"
Thanks so much for writing all this Great information on our VM motor!

Rixram · **Posted:** Fri Aug 28, 2015 10:04 am

pjigar wrote:

flash7210 wrote:

What tires do you have?

A suspension lift can hurt your MPG.

A ECU tune doesnt always hurt your MPG, but usually the extra power makes folks want to push the accelerator pedal harder.

I have normal street tires, 225 75R16. I am trying to be easy on the paddle and I am going to stock just to compare.

Anyone know how much a lift cost in terms of fuel economy?

I put a 2 or 2.5" Skyjacker on in 2012. Also went with larger tires (245/75/16) All Terrains. I lost about 1-1.5 mpg overall (hand calculated).

pjigar · **Posted:** Mon Aug 31, 2015 11:39 pm

Here are my highway GPS MPG, full tank to full tank, hand calculated, with Yeti 808 mild tune, 70 to 80 MPH speed.
21.4 MPG going against the wind. Dallas to Austin. Not a whole lot more compared to stock tune.

Rixram · **Posted:** Tue Sep 01, 2015 12:31 am

pjigar wrote:

Here are my highway GPS MPG, full tank to full tank, hand calculated, with Yeti 808 mild tune, 70 to 80 MPH speed.
21.4 MPG going against the wind. Dallas to Austin. Not a whole lot more compared to stock tune.

80 mph and into the wind? That is actually pretty good! I drive 60.

pjigar · **Posted:** Tue Sep 01, 2015 12:50 am

Rixram wrote:

pjigar wrote:

Here are my highway GPS MPG, full tank to full tank, hand calculated, with Yeti 808 mild tune, 70 to 80 MPH speed.
21.4 MPG going against the wind. Dallas to Austin. Not a whole lot more compared to stock tune.

80 mph and into the wind? That is actually pretty good! I drive 60.

I feel good now! I am sure I will cross 28-29 going with wind on the way back to Dallas.

thermorex · **Posted:** Tue Sep 01, 2015 2:53 pm

pjigar wrote:

Rixram wrote:

pjigar wrote:

Here are my highway GPS MPG, full tank to full tank, hand calculated, with Yeti 808 mild tune, 70 to 80 MPH speed.
21.4 MPG going against the wind. Dallas to Austin. Not a whole lot more compared to stock tune.

80 mph and into the wind? That is actually pretty good! I drive 60.

I feel good now! I am sure I will cross 28-29 going with wind on the way back to Dallas.

If you lower to 70mph you'll get couple mpg for sure.

ATXKJ · **Posted:** Tue Sep 01, 2015 6:48 pm

thermorex wrote:

If you lower to 70mph you'll get couple mpg for sure.

That is - if they can scrape your Jeep off of the truck that tries to run over you...

I35 is not a relaxing drive,

75-80 is much safer

(NAFTA and trucks going from Mexico to points North - they're in a hurry)

thermorex · **Posted:** Wed Sep 02, 2015 5:47 pm

ATXKJ wrote:

thermorex wrote:

If you lower to 70mph you'll get couple mpg for sure.

That is - if they can scrape your Jeep off of the truck that tries to run over you...

I35 is not a relaxing drive,

75-80 is much safer

(NAFTA and trucks going from Mexico to points North - they're in a hurry)

Then write a "speed kills" on the tailgate, lol. But I get your point, sometimes low speed is quite unsafe.

Poor fuel economy

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