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Farout
Long Term Main Page
2005 Jeep Liberty CRD
Date: October 2005 Miles: 5,300
A good sport of another kind is the Jeep Liberty CRD. This common rail turbo-diesel SUV is Chrysler's way of testing the waters for European-style diesel people movers. And, despite a premium price, the CRD is selling well. The reason is of course better fuel economy, or the promise of it. Our Limited 4X4 has so far averaged 21.5 miles per gallon in 5,300 miles of mixed driving. That's about 10% less than in our original test, but about 15% better than the gas V-6 Liberty we tested earlier. Since mileage is still climbing we think it will get better. The 160-horsepower 2.8-liter inline-4 turbo diesel is not as quiet at launch as some diesels we've driven, but it's still not at all intrusive during cruise.
Date: January 2006 Miles: 8,000
Long before Americans became enamored with gasoline electric hybrids, Europeans discovered fuel efficient diesel power, like our 2005 Jeep Liberty CRD. In fact, the Jeep's 2.8-liter turbocharged 4-cylinder diesel is the same powertrain Jeep uses overseas. So while it still has a rather loud clatter, it's clean-burning design has none of the sooty stigma once associated with diesels.
While its 160 horsepower is modest, it is the generous 295 pound-feet of torque that makes this Liberty CRD perform close to a V6 gas powered Liberty. Plus, mileage of 23.2 per gallon is about 25% better than a V6. And it has been totally reliable. After five months and over 8,000 miles, except for an oil change, our Liberty has not seen the inside of a service bay. And cold weather or hot, it starts quickly. But as long as diesel fuel remains pricier than gas, it is unlikely that diesels will become widely popular here. But if the moon and stars ever do align, the Jeep Liberty CRD shows us that this fuel saving technology is ready to go.
Date: February 2006 Miles: 12,000
In Europe, it's hard to find an SUV that isn't a diesel, like our 2005 Jeep Liberty CRD. In fact, its turbocharged 4-cylinder is the same diesel Jeep uses overseas. Made by corporate cousin MV Motori in Italy, the 2.8-liter combines a modest 160 horsepower with a substantial 295 pound-feet of torque. In fact, it accelerates faster than the gas Liberty V6.
And fuel economy is better too, although not as good as we had hoped. After 12,000 miles in five months, we're only averaging 21.7 miles per gallon. That's about 10% better than the gas V6. Unfortunately since in many parts of the country diesel fuel is about 10% more than regular gas, operating savings are neutralized. On the other hand, the cost of choosing the turbo diesel over the gas V6 is only about $1,500. So that, combined with its high torque delivery, is fueling Liberty CRD diesel sales to capacity.
Thanks for the translation!
caribou1,
Does this mean that you had the shudder at ~53mph but got it to go away by turning EGR off?
farout,
Mine has always, and still does, go into 5th lockup at ~53mph. My mileage has been pretty consistently around 24 to 25mpg. The only time it was lower was when running off of winter fuel (~23mpg). My drive is ~80% highway ~70mph.
crdblazr,
My service center replaced my transmission control module b/c my check engine light was on, that did not fix the problem though. They finally ended up replacing the front pump and the problem went away. The shudder, which is seperate from the check engine light issue, has been greatly reduced after all of this but I can still get it to happen.
Sounds like there are a few different calibrations running out there... Quite a few people here mentioned that their CRD would not go into 5 lockup until ~62mph. I can't see how a new control module on it's own would fix this, there had to be a new calibration in the module.
Ran a tank of B10 a few weeks ago....no noticable change in performance or fuel economy. Currently running straight diesel with Power Service....can't tell any difference in performance, but I'm curious to see what happens with fuel economy. Has anybody who has used PS noticed a large enough increase in mileage to justify the cost? I know months ago there were some discussions on this, but now that we all have more mileage, any updates from anyone? Diesel is still $2.75 in DFW, so even a couple mpg improvements would pay for the bottle of PS.
Twocycle2
Second Report
Jeep Liberty Sport CRD
A Jeep Liberty is meant to haul stuff, run dirt roads and tackle snowy hills. We did all that. But, we also took it on a trek from frigid New England to Florida and back. Once we adjusted to the diesel noise, the ride was comfortable. The smallish cargo space held everything we wanted, handling wasn't bad and the fuel stops were minimal. But no sooner did we get back home than the check-engine warning light came on. Manhattan Jeep replaced the EGR valve, but the light's come back on. And the Liberty's back in the shop. --JERRY BEILINSON
DATA SO FAR
Price as tested: $28,045
Previous reports: See 12/05 Miles driven: 12,725
Miles since last report: 10,171
Fuel economy: Average-20.1 mpg, Worst-17.8 mpg, Best-29.7 mpg
About the cruise control: Are you saying that with the cruise control on it is supposed to stay in the same gear? This is the first auto transmission I've had in a decade so I guess maybe I don't know any better. With my CRD it changes gears fairly frequently with the cruise on, depending on the pitch of the road.
It sounds like the PCM may be the issue, so I guess I'll need to head back to the dealer...
There are several things related to the malfunction of the egr valve, understanding that when the valve is defective it stays stuck in the "open" position, somewhere between 0 and 100% of it's travel.
This valve opens only when there is minimal or no load on the engine, in other words when the road is flat or/and when the gas pedal/sensor is just about leaving the relaxed position (foot off).
I've often experienced very long delays for the engine to rev up while going through tiny village roads at 25 mph. The engine regularly performed as if it was stalling or as if the transmission wasn't letting go the converter clutch. This was the main sympthom.
Then later on I felt the transmission was shifting faster when I had a 'certain' load on the engine. With the gas pedal pressed 1/2 way down all went perfect. So I decided to provocate the shuddering effect by letting go the gas pedal when shifting, and it did hesitate.
Concerning the shifting speed of the 5th gear, it is variable on this vehicle. The minimal speed is ~53mph and can be taken to ~75mph on mine depending on the throttle position. This is why shifting at the lowest speed corresponds to when the egr valve does it's process. There are often conflicts or interactions due to different response times between the two. I would just accelerate a bit more to get out of this band.
The last but not least funny thing is related to mileage. Without the egr valve I get better mileage with the K&N air filter. Was the fuel-air mixture so lean because of the higher airflow that the engine burned more fuel inefficiently?
Six-two is too high a speed, unless you really have your foot into it.
I use this method consistently, head wind or not. And no one has ever burned out their horn.
I've never experienced this, but I do only get the shudder at 53mph after hard acceleration and backing off of the throttle to stay around 53mph which seems to agree with your theory of the shudder being related to light throttle. I'm a bit confused why VM would only use EGR when there is little or no load? EGR is used to reduce NOx and NOx is produced at higher loads as well. Did this EGR sticking issue you're speaking of light any lamps on the dash?
The last but not least funny thing is related to mileage. Without the egr valve I get better mileage with the K&N air filter. Was the fuel-air mixture so lean because of the higher airflow that the engine burned more fuel inefficiently?
No EGR causes higher pressure at the turbine inlet which will speed up the turbo and can cause more boost for a given VGT position. On the other hand you're robbing the intake of the EGR it used to have. So I don't know if you have more or less "air" without EGR? Probably depends on how VM is controlling things. I would think since you got better fuel economy without EGR that the conditions you were operating at had a net effect of more "air" than with EGR on. Did you notice a difference in fuel economy with just the K&N filter?
This valve opens only when there is minimal or no load on the engine,
On a recent trip I observed what you describe with respect to the EGR valve being more open at light throttle. While traveling at 65 mph and getting 29.1 mpg (calculated!) the IAT (input air temp) ran around 155-160 F while the WT ran around 173 F (when the ScanGauge was working). In the destination area driving at varying speeds of 50 to 65 in overdrive(s) the IAT ran 150 - 158 F while the WT ran at around 170 to 173 F.
Just for an experiment, I drove out of overdrive at 55 mph for an extended period (10 miles, maybe) and the IAT increased to 182 F and the WT increased to 182 F. So, under a lighter load but higher RPM the EGR valve apparently opened further and the WT increased because the engine is less efficient at higher RPM and lower boost while receiving more EGR. On one long uphill I floored it and ran up to 3500 RPM. The WT remained the same but the IAT dropped during acceleration. While plodding around between 15 to 35 mph in a very hilly curvy area I saw IAT at 188 F and WT at 195 F. The engine always seemed to have good throttle response, though.
And, guess what? When I let off the throttle after the wide open pull and slowed back to 55 the engine had mild surging. I shifted immediately into OD and the surging turned to jerking – on the order of 3 to 5 Hz. I haven’t floored my CRD or had jerking for so long I can’t remember when it last happened – 10,000 miles ago, maybe. My hypothesis is that the EGR valve is too slow to respond to quick and extreme changes in throttle/load/turbo conditions or the computer is too quick or too slow to respond to transient conditions and gets loopy. Recall, I drive very easy and do not “blow its nose” and have had virtually no jerking until I drove extremely this day. It just does not feel like the transmission is the source to me.
Outside temperature during the entire drive was in a narrow range of 85 to 90 F and all of the readings are from memory. The temperature gauge is calibrated in 10 F increments until it nears midrange. The temperature gauge never went above midrange or half a tick mark below midrange after warm-up. Temperatures from 170 to 195 F are crammed into a 5 degree range on the temperature gauge – huh? The readings on the ScanGauge are what the CRD reports to the unit.
On the trip home, I passed three separate cars on 2-lane that were driving at 50 mph. I pushed the throttle lightly and deliberately and the transmission shifted from 4th to 5th gear during each pass and scooted right around and then slowed back to 55 to 60 with no jerking. It takes a little mental discipline to pass on 2-lane with out flooring the throttle. Return mileage was 31.4 mpg (calculated!!) driving at 65 mph (355 m / 11.3 gal). I spent a lot of time cramming the tank on fill-up to make sure it was not a miss read due to not getting the tank full (fuel standing in neck when done).
I’m back in my 4 cylinder Japanese car for my daily 3-mile commute and I find the fine running but high revving engine almost annoying. All future vehicles, if possible, will be diesel. I am ruined on gas.
Rkernbob, the short answer is that in a diesel engine at idle the mixture is around 40 to 1 which creates the most NOx while at full load the mixture is around 18 to 1 which creates the least NOx. It is excess oxygen and high combustion temperature that produces NOx. EGR lowers the combustion temperature by reducing the available oxygen.
Also, my check engine light came on at about 11,000 miles and it turned out the EGR was the problem. the test box indicated a problem with the turbo boost but the mechanic knew enough about the entire operation of the system to blame the EGR. He replaced it and the problem was solved.
So, if you take your Liberty to a dealer with a check engine light that indicates a similar problem suggest they change the EGR valve because there have been several other owners who needed one replaced between 10000 and 15000 miles. IN fact I haven't written or talked to one owner who got more then 15000 miles on the EGR. Maybe this fall when the ULTRA LOW SULFUR comes to market the egr valves will last a bit longer.
PS On a recent trip I filled with biodiesel and as soon as I was back on the interstate, I saw the fuel mileage climb to 29.5 at 70mph with the cruise turned on. That is the best mileage I saw on the entire trip of 2000 miles!
I agree with your evaluation of the amount of time these units spend in the shop. The first four months I had it, it spent about 5 weeks in the repair shop!! This was due to the fact that STAR was not ready to release EGR valves or anything else. Probably because they were trying to re-design the existing parts that gave them the problems.
I also have to wonder about the selection of a tranny that was designed for a a high revving gas engine. But I digress, we are, after all, the test market consumers!! :surprise:
Or go to Google and do a search for (liberty accessories) and its the 3rd link.
Cabelas.com has hitch extensions in 3 different lengths, with and without step plates. Good prices too!
Good luck! LK
PS! They are 7", 14", and 18".
Rocky has 12".
I am running Amsoil products in my CRD, including cetane boost, the heavy duty injector cleaner(ADC),and the 15W-40 full synthetic oil.
I have just over 9800 miles on my May 2005 build CRD and so far so good with the EGR. I still blow it's nose weekly. Do not know if this helps but it cannot hurt.
Having a one piece stinger made to your exact length is the best way to solve this problem.
Also have them put 4 small weld beads (one on each flat) close to the where the stinger fits into receiver. Then take it home and grind down the beads so the stinger fits into the receiver tight. This solved two problems.
Also note that if you put on a drop stinger (say 3 inches) you will have plenty of top clearance. I tow a travel trailer that needs 20 inches off the ground to be level so a drop stinger would not work for my application.
http://www.detnews.com/apps/pbcs.dll/article?AID=/20060601/AUTO01/606010346/1148-
Grand Cherokee diesel MB engine
I've been using Phillips 66 mostly, and occasionally tried Conoco. My husband's Dodge diesel never liked Shell, so we never tried it. We'll I filled up at Shell station and then put HALF a bottle of 'Red Line synthetic oil diesel fuel catalyst' in the tank and NO MORE SHUDDER. Not even once the whole tank through. 2nd tank of Shell I added 2 ounces Red line, still no shudder.
The present tank is Phillips 66 diesel and the shudder came back within 5 miles. I didn't have the Red Line on me, but will be adding 2 ounces to this tank and giving it a try today on my trip into town. After this tank, I'll try the Shell alone without the Red Line to see how much this additive helped. We'll change out the fuel filter once the new ULSD hits the stations here, but looks like I'm sticking with Shell for fill ups for a while.
Maybe mine is fuel related after all! I'm just over 5500 miles now. This shudder has been with me since day 1 and it's sure been nice to be without it for the last 2 tanks of fuel.
Michelle
Several other problems but not that.
have 12,000 miles on my crd. looks like i am supposed to change the front and rear differential fluid. this seems like very little mileage for this service. is this correct? if i do need to perform this service, is it something i could do my self? want to change it over to amsoil fluids if i can.
thanks
e.t.
I sure hope DCX reads all this test market data we keep sharing, so the next diesel owners won't pay so much to be DCX's test market. That's what we are is a "test market" and that sucks.
Farout
Jeep Grand Cherokee Diesel to Make 2007 Debut (Inside Line)
Maybe your testing has paid off (but note the choice of engines)?
Steve, Host
"From Internal Combustion Engine Fundamentals", John B. Heywood...
"At high load, with higher peak pressures, and hence temperatures, and larger regions of close-to-stoichiometric burned gas, NO levels increase. Both NO and NOx concentratinos were measured; NO2 is 10 to 20 percent of total NOx."
However, Heywood goes on to show that NOx decreases as the equivalence ratio decreases which agrees with your comment.
All I'm trying to say is that I doubt the VM engine is only flowing EGR at low throttle input. I have no way to back this up because I did not design the engine and I don't know of a good way to monitor what's going on. But I'm guessing they would have a hard time meeting emissions without flowing EGR under load as well.
EGR %, RPM, Load
0, 675, 0
21.7, 1000, 25
11.4, 1000, 50
0.5, 1000, 75
0.3, 1000, 100
28.7, 2500, 10
21.9, 2500, 25
11.9, 2500, 50
1, 2500, 70
0.5, 2500, 100
0, 4000, 25
0, 4000, 50
0, 4000, 75
What is displayed is an EGR valve that is closed at high load and high RPM and open at low RPM and light load. Low RPM and light load is where my engine is operated 99% of the time.
Agree with you on this one... Sounds like it is flowing more EGR at lighter loads since the intake manifold temp went up. I still don't agree with caribou1's statement of...
"This valve opens only when there is minimal or no load on the engine"
I think the valve is open a lot during operation, not just light load. Maybe it's opening up a lot at light load but I doubt only at light load.
Maybe it's the EGR valve... Maybe it's the transmission... Maybe it's the fuel. I really don't know and I don't think that any of us truely know as "nescosmo" suggested. All we can do is give our thoughts.
Regardless... I agree that the VM may be opening up the EGR valve a lot at low loads. I just disagree with the idea that it is not flowing any at all at higher loads. Either way the theory you and Caribou1 have could be true.
What do you think of that ScanGauge you have? I've been thinking about setting up a DAQ system and tapping into VM's sensors, but I can't decide whether to put the time and effort into it. If you don't mind me asking what did you pay for it?
On the source of the data, I found a lot of technical papers with similar and a little different data and just printed these data without making sure the source was on the page. I could go looking for it again, but my home internet link is too slow. These data may or may not be quite different from the CRD (the torque was 131 lb-ft at 70% load, so maybe around 100-110HP, TDI?). I honestly don't know. I do know that on a wide open pull the IAT on my CRD dropped to around 130 F when the outside temp was 90 F and there had to be some residual heat left after the intercooler. None of this proves that the CRD EGR closes at full load absolutely.
Not to change the subject, but I am pretty enthused about Farout's recent result. It sounds like the Bosch PCM might be a silver bullet, at least in his case. Can't wait to see what happens to his mileage and how his engine/transmission acts longer term with the new PCM.
You have a good point. Other than the inconvenience of draining and replacing expensive antifreeze, the EGR removal/replacement appears to be a simple task. The puzzling thing seems to be that no dealer, according to this forum, has cleaned and replaced the same EGR valve. They are just being replaced with new. I wonder what this thing costs and will the replacement be better quality? Also, I have to wonder, given the multiple replacement of EGR valves that some have had, if the EGR valves were actually bad, even. I really like this vehicle and want to keep it because of its unique combination of capabilities.
I am reading and hearing mixed information on the new fuel. Supposedly, ULSD will have the proper lubricity to take care of the injector pumps. Can we count on that? :confuse: