I've just completed a 3300 mile round trip from St. Louis to Las Vegas and thought I'd share my experiance with my newly acquired 2006 CRD with you all. I should say that before leaving I did my own version of the EHM and although I played with the ORM and almost drove it that way, I ultimately decided not to because I wanted to be aware of any engine problems that could pop up and wanted a clear CEL. We left St. Louis on a warm afternoon with the windows down and the sunroof open. Eager to make some good progress, we cruised at about 80-85 mph all the way to Salina KS. The CRD performed flawlessly, but on fill up she got a measely 22.5 mpg.
I decided to slow it down the next day and see what we could get out of her. I kept it under 75 for the next tank and was rewarded with 24.5 mpg's. We arrived in Colorado springs and filled up, fully expecting a big drop in mpg's since we were about to do a LOT of mountain driving. After climbing pikes peak and burning the rest of a tank averaging 60 mph on steep grades, somehow the little oil burner whacked out 27 mpg's! It obviously does better at lower speeds, regardless of load caused by grade.
Well, as we were approaching Vegas I noticed something funny. After a long highway run we stopped to eat lunch at a truck stop. Upon start up after sitting for about 30 minutes it sounded as if it had a miss when I took off. As soon as I cracked the throttle good it cleared and ran fine, but upon repeating this scenario over the next few days it did this every time and got a little worse. Also it felt like the turbo lag was getting worse.
Once we were in Vegas I decided to try something. On start up I fired it up, waited a few seconds, then revved it up a bit. I though it might clear it out but instead the check engine light came on. Feeling a bit nervous about being 1600 miles from home with a cel I ran to Oriellys to have it scanned. It came back as a "low boost condition". So I spent a little while listening and checking things over and couldn't detect any obvious boost noises from the hoses or anything of that sort. The one thing that was in the back of my mind was the idea of egr caking the turbine vanes and causing issues, so I decided to pull the maf and see what happens.
What happened next was the thing ran like a top! Upon pulling the maf the lag dissappeared, performance increased substantially, and it was running great. The first tank back through the mountains only got 25 mpgs, but the next two tanks cruising at 80+ mph got 27-28 mpg. I think my theory was right; the turbo was getting clobbered by soot all the way there and didn't like it one bit, but with the egr unhooked it cleared out and ran great.

So, that is my personal testimonial to the terrible emissions set up on this thing. She's still running great with the orm done while I save for a GDE EcoTune. I can't wait to get it done and "fix" the egr issue for good.

Wonder if the EGR/FCV are failing on you... sounds like that 'tune' is just the ticket!

Congratulations on the new family member!

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2005 Liberty CRD
2004.5 Cummins 5.9L TD, F1s, NV5600 6-speed in a '93 GMC Suburban

Having put 150,000 miles now on my 2005 CRD, I can tell you for sure that speed kills your mileage. Frankly, this little tractor has all the aerodynamic advantages of a cinderblock, and mileage drops off rather rapidly above the sweet spot of 60 mph. 60 will get you into top gear with the torque converter just locked up. Drop back to 57, and the TC unlocks, go up to 65 and wind resistance starts to rise like a rocket.

For mpg I'm fond of 62mph/1,800rpm which is a speed and rpm you can easily hold on a pre/post F-37 TCM or GDE TCM tune. Go to 70-75mph will cost 10-15% in mpg or worse if there is a head wind. At that mph/rpm I can get an honest hand calculated 32+mpg.

Of course low boost (stuck vanes=need for Italian tuneup; leaky boost hoses=need for Samcos; bad boost solenoid=need for new boost solenoid) or clogged MAP sensor (never mind FCV/EGR) won't help. Unplugging MAF will disable EGR and will certainly help if EGR is clogged as it was in first 100miles of operation new.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

All my mpg figures were hand calculated using my gps, so I bet since I was getting 27mpg's at 80 mph on the way home I could have slowed down to 60 or 65 and got an honest 30 mpg. I just can't believe the difference between my first tank on the way there and my last tank on the way back. Unplugging the maf made at least a 5 mpg difference at 80 mph. It probably is an even bigger difference because we took I-70 heading out (all flat farmland to CO) and came back I-40 (a lot more hills in MO once it becomes I-44).

I'm just happy it ran great after the ORM. We went to Vegas to get married and didn't need any stupid problems putting a damper on things.

On a side note, it was fun driving route 66 (I-40). We stopped at a few neat old timey places along the way.

3 miles per gallon difference or 20 miles per hour difference... Hmm.

My typical trip into Florida is 450 miles one way, almost exactly. That would be 7.5 hours at 60mph **IF** you didn't have to stop for fuel and "other" needs. Of course you do need to stop.
At 80mph, that trip is 5.6 hours, again, just driving.

The difference in fuel:
60mph, 450 miles, assume 30mpg. I come up with 15 gallons of fuel.
80mph, 450 miles, assume 27mpg... 16.6 gallons. $6 (at today's extortion prices) for not needing to be stuck in my SUV for an additional 2 hours? HELL YES I will pay that, my time is far more valuable than that.

When I "take it slow" on those trips (and I make that drive a LOT, I drive about 35k per year) that trip takes on the order of 10 hours with stops, including at least one stop where I'm just relaxing and eating dinner. When I'm on the move and need to get to the destination... Just under 7 hours was my best time, because I'm actually doing 75 or so, I don't need any more tickets.

It is all about compromises.

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Proud supporting vendor of LOST Jeeps
TRAVELING CRD TECH. I come to you!
Need help? Just ask! I've taken it apart more than most.
Email jeep [at] maincomputer [dot] com - BOARD MESSAGING IS BROKEN
Over 225 CRDs currently driving with my valves, timing belt, rockers, or ARP Studs.
Bad noises = REALLY bad things.

Now picture it being 1600 miles one way! Yeah, there was no way I was doing less than 75 mph, especially since I got the wrong cruise parts and didn't get it installed before we left. That was my only regret. I actually had a bruise on the side of my foot from driving that far with no cruise, which turned worse after walking 5 miles a day in Vegas. Advil and beer were my friends...

When my wife drives to work everyday she does 80 mph. We are running WVO and the fuel is very cheap, free for all practical purposes. This weekend we drove to orlando for a wedding and the disance is very close to the capacity of the Waste Veg Oil tanks. So I drove the speed limit of 65 and I took the non toll roads in an effort to make it there and back on one tank of fuel. And paying $20 to save 20 miles seem like a bad decission.

Speed really does make a diffence but it is not the same on all cars. Highest fuel mileage I ever recorded was on my 2000 Corvette Hardtop. I drove 49 mph for 2 hours thought the middle of FL in 6th gear. The trip gauge computer read 50-53 mpg the whole trip. When I filled the tank I recorded 48 mpg. That thing was just above idle. My 1985 Mazda RX-7 I drove from the far west of florida near LA to Jacksonville at over 100mph for most of the trip it was near redline. It got 27 mpg. Doing 60mph on the way there I only got 26 those were just not efficient engines running slow. That Corvette would regularly get 30mpg at highway speed of 65-70. Around town it would get 16.

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2006 Liberty CRD -- Spare tire replaced with Veg tank, semi filter for veg, FPHE, Electric common rail line heater, fill vegetable oil tank every 3 days. ORM, EHM comes out in front of the passenger rear tire. Wife has new job and 20 mile round trip to work. I borrow her Jeep a lot and live in South Florida.

Was your RX-7 the fuel injected version? In 85 you could get a carbed 12A or an injected 13B in the GSL-SE. I had an 85 with the 12A and it got mid teens no matter what I did (although most of the time I was running the pee-wads out of it! Loved hearing that rotary sing...).