Fuel economy - CRD Owners in Texas / San Antonio

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

I got my CRD about 2 months ago and in that time I have cleaned out the existing EGR system, replaced the glow plugs with 7v Etechno1s, installed a K&N air filter, replaced the fuel bridge with a brass union, replaced the fuel filter with a WIX brand filter, and performed basic fluid changes. The fuel economy started out around 10-11 mpgs which I figured was due to a broken fuel bridge. The fuel economy is still hovering around 13 even after all these improvements. I wanted to see if anyone has ideas outside of the continuing troubleshooting I have listed below?

Check for leaking injector seals
Replace the MAP sensor (I cleaned mine and discovered it was partially broken)
Possibly replace fuel injector return line

Aside from that, wondering if there are any CRD owners in Texas or specifically in the San Antonio area...local Jeep dealer says there is a fella that owns four of them that he gets parts from them occasionally?

Happy Jeeping folks and thanks for any ideas

flash7210 · **Posted:** Sun Jul 30, 2017 2:36 pm

Are you using the overhead display for MPG or calculating by hand?

Are you getting black smoke out the exhaust?

Do you have any fuel leaks?
I wouldnt go replacing any fuel lines unless they are leaking.

Things that will hurt MPG.
Roof rack.
Oversize offroad tires.
Driving short distances that dont allow the engine to warm up.
Driving style.

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

I calculated it manually, not trusting the overhead to give me correct results. Only black smoke under heavy accelleration off the line which is rare, I have not gotten on this motor much as it is due for a timing belt replacement which is the next major job. I have only replaced the fuel line to the boost pump, which again I still have about 2 mpg better than I did. I feel that the bad MAP sensor is a big contributor to the problem and I am ordering a new one next week. No obvious fuel leaks but I have worked on many Jeep motors and the quality control on the base o-rings to the injectors was always a problem, unsure if similar ones are used on this Italian diesel implant. It has slightly larger BF Goodrich tires but I would only expect a 3-5 mpg drop from the added road friction...I am 10 mpg lower than what I should be seeing under ideal circumstances. No roof rack and other add-ons ....and I have been allowing the motor to idle for 3-5 mins to warm up....you and I have similar thoughts on all these things. If the MAP replacement doesn't improve matters, I am looking at replacing the Crankcase Ventilation Valve with perhaps a Provent 200. The carbon buildup in the EGR to intake elbow and on the MAP was about as bad as you could get and I cleanup it up spic and span. Next thing I might look at is the injector bases. I am performing the EGR delete at the same time I do the timing belt job.

Thanks for the thoughts, sounds like great minds think alike

WWDiesel · **Posted:** Sun Jul 30, 2017 5:13 pm

What is the engine temperature running at going down the road? Gauge should be just a tick left of 12:00 if thermostat is working properly.
Engine running too cold (bad thermostat) will increase fuel consumption.
Also, loosing boost back through EGR valve or a small boost leak will cause poor mileage.

You can block off the EGR feed tube with a simple block off plate that you can make out of most any piece of thin metal like a soup can lid or something similar. :wink:

See this post for Block off plate dimensions and instructions:
viewtopic.php?f=5&t=76576

Long term, it is best to install the Weeks (Sasquatch) elbow kit! It allows you to completely remove the EGR valve, EGR cooler, FCV, and all associated cooling hoses and plumbing. :BANANA:

Go here to view:
https://shop.sasquatchparts.com/product ... berty-crd/

Map sensor:
You can replace the MAP with a GM Part No. 55206797 sensor for ~20 bucks found on line.
Many members are using these instead of the high priced Mopar sensor!

flash7210 · **Posted:** Sun Jul 30, 2017 5:16 pm

Fuel filter was a good place to start.
MAP sensor is the next logical step.

Unless they are leaking, fuel return lines won't effect MPG.

A stuck open EGR valve could effect MPG. Deleting it is a good idea.
Leaking boost hoses and/or intercooler will hurt MPG.
Also, check you turbo inlet hose for holes.

The crankcase vent won't hurt MPG but it will allow oil to ge into the intake path which will cause the turbo inlet hose and boost hoses to deteriorate.
Adding a provent is always a good idea.

The injector seals shouldn't be leaking. Unless maybe they were removed and not installed properly. They seal up using copper crush washers which must be replaced every time an injector is removed. If they were leaking you would probably be able to hear or feel combustion gasses escaping.

Being that you live in Texas and it's summertime, I'm not worried about your engine running too cool.

GordnadoCRD · **Posted:** Sun Jul 30, 2017 6:28 pm

Your K&N air filter could be an issue, if it's the oil type. They tend to not breathe as well as the stock, and plug up much faster with a diesel than with a gas engine (no throttle, always full air flow)

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

Thanks for all the replies! I appreciate the GM part number equivalent for the MAP and it will be replaced next week. I inspected the intercooler return hose for any leaks and it looks fine. I will still likely replace it with a SAMCO. Engine temperature has been perfect but the timing belt replacement will include installation of a Graf water pump and a thermostat at the same time. It will likely be a job I will undertake over the fall months as it is near record temps here in San Antonio presently...needless to say the Jeep has past the test for endurance in hot temps and still sits just as ya'll suggested just a tic off from 12:00 position. The K&N filter was just installed and hasn't had enough running time to develop anything that may seem to restrict it....I have good confidence it work fine as long as it is maintained, I check the air filter every oil change in other vehicles I have restored. One of my last restorations was a Toyota Land Cruiser FJ80 with the iron block straight six. It was notorious for poor fuel economy and the air filter was usually suspect number one if it ever dropped to 10 mpg. As I suggested, I replaced the fuel filter. Thanks also for the info on the injectors, as I was unaware it had copper crush washers instead of those green o-rings that tend to leak on other Chrysler / Jeep engines. I have had a Dodge 5.9 truck, a Town and Country 3.8 V6 and several Cherokees and Grand Cherokees all of which suffer from leaky and expensive injector maladies. One of the cost saving efforts on a reasonably functioning injector was to simply replace their seals. Is there any reason to pull the injectors and test them at this point do you think? I understand a special puller may be required to extract them also. Thanks for all the thoughts on this, all valuable input

WWDiesel · **Posted:** Sun Jul 30, 2017 9:46 pm

A little more info on the K&N Filter issue! While I love K&N filters, unfortunately they are not a good filter for a Jeep CRD and this is why!
K&N's have to be oiled to allow the cotton filter material to work at its optimum, and the oil that is applied to the filter material migrates into and onto the MAF sensor and will eventually trip a code when the MAP gets dirty enough from the oil contaminate...
I speak from experience as I installed a K&N in my Jeep CRD and it started giving DTC's concerning the MAF sensor. I would clean the MAF with the special spray and it kept returning so I went back to the original paper type air filter and have not gotten any more DTC's since on the MAF!

I like K&N air filters; I have them on both my Dodge trucks, one a 360 gasser, and the other a Cummins diesel with the biggest K&N filter they make.
But the nice thing on my Cummins Dodge, it does not have MAF sensor, EGR or any of that junk to cause problems with an oiled filter....

:SOMBRERO:

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

Thanks for the info on the K&N! It is my understanding that I can disconnect the MAF Sensor once the EGR delete is performed. Some time after all the timing belt work I intend to send the ECU off to be re-programmed (sure is expensive to do so, sounds like it's $750?). I'll check into installing a normal filter if I can't run without the MAF sensor feeding info to the ECU, but I would like to retain the filtering properties of the K&N sometime down the road. Once the two big hurdles of the EGR delete / timing belt water pump thermostat and ECU re-program are done I will look into things like installing an ARB bumper, lift and so forth. I wanted to get the fuel economy as best as it can be prior do doing any of those mods since they will also dramatically effect gas mileage. The ultimate goal here is to travel back to Colorado where I was stationed years ago and enjoy the mountains in what I feel is one of Jeep's best and sadly underproduced models with the turbo diesel. That's a long drive from south Texas and any improvements in fuel economy are likely good for it's longevity

Thanks again and happy Jeepin'

GordnadoCRD · **Posted:** Sun Jul 30, 2017 11:21 pm

My understanding is in recent years, K&N has followed others in producing cleanable dry media filters.
I have no experience with these, so don't know anything about effectiveness or efficiency.
If any others out there know more about these, please share!

I've had K&N on nearly every gas engine vehicle I've ever had, but they've always suffered on diesels, requiring very frequent cleanings, and actually lowering power at higher rpms.

TKB4 · **Posted:** Mon Jul 31, 2017 4:43 am

If you are speaking of the GDE tune in the future I believe the current price is $500.
http://www.greendieselengineering.com/S ... ++++++++++
The addition of oversize tires has actually made some improvement in my fuel economy. I believe this is due to the same effect as lowering the differential gear ratio. I would assume, however that the wider the tire the less fuel economy. I have 32.1 inch tires ( 255/75/18 Duelers with 1 inch spacers) on CRD with approximately 2 1/2 inch lift that gets about same mileage as the stock tires and at 1750 RPM in top gear OD goes about 65MPH this is roughly 12 % oversize and is essentially the largest diameter that will fit the CRD due to the pinch weld at firewall in front wheel well and it will still rub slightly in some situations. These are take off tire and wheels from Sahara jeep wrangler.

The firestone destinations (245/75/17) fit similarly on a non lifted jeep and are about 8% oversized.

You would not want to use tire wheel combinations quite this tall with similar degree of lift if you plan to do much trail riding. I use mine for off road in mud for hunting and every day driving.

For improved economy and longer tire wear since they go further than stock for each revolution I would go with about a 31 inch tire /wheel combination. Of course you can do this when new tires are needed anyway and not cost any additional money.

papaindigo · **Posted:** Mon Jul 31, 2017 6:37 am

Check for dragging brakes.

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

Thanks for the info on the GDE tune, incidentally I found out it runs $500 right after I posted that message lol. Anyways, it sounds like the change in transmission ratios is part of that tune? Or is it part of the $300 transmission tune that they have? At any rate I guess I think I will look into remapping options like the MPPS V13.02 and the maps that folks have posted as its a cheap option to play with the computer before I decide to send off that much to GDE (although I am sure it sounds like they do a great job as I understand it). I have also seen the Kess V2 with the ECM Titanium add on and would like to see how much tuneability it offers, looks like a pretty concise package for cheap versus options like the AUTEL Maxidas or others. Incidentally I bought my Jeep with no factory keys (clean blue title of course) so I have to get a setup that can program a new set of keys as well other than the Chrysler DRB3 tool. I'll pass along the info on how that goes when I get to it.

As far as dragging brakes go, I hadn't considered that as a possibility but it's something to look at. I would be surprised since it has excellent pickup off the line and at speed but since its such a torquey motor, its worth looking at. I intended to perform a brake overhaul this winter as well.

Thanks for the new ideas and info, Happy Jeepin!

WWDiesel · **Posted:** Mon Jul 31, 2017 9:07 am

TexMech wrote:

Thanks for the info on the K&N! It is my understanding that I can disconnect the MAF Sensor once the EGR delete is performed. Some time after all the timing belt work I intend to send the ECU off to be re-programmed (sure is expensive to do so, sounds like it's $750?). I'll check into installing a normal filter if I can't run without the MAF sensor feeding info to the ECU, but I would like to retain the filtering properties of the K&N sometime down the road. Once the two big hurdles of the EGR delete / timing belt water pump thermostat and ECU re-program are done I will look into things like installing an ARB bumper, lift and so forth. I wanted to get the fuel economy as best as it can be prior do doing any of those mods since they will also dramatically effect gas mileage. The ultimate goal here is to travel back to Colorado where I was stationed years ago and enjoy the mountains in what I feel is one of Jeep's best and sadly underproduced models with the turbo diesel. That's a long drive from south Texas and any improvements in fuel economy are likely good for it's longevity

Thanks again and happy Jeepin'

You can unplug the MAF and it will disable the EGR electronically but it will set a DTC as long as you leave it unplugged! The MAF is used by the vehicle electronics to operate the EGR & FCV!
Even if you unplug the MAF and leave it unplugged, you should still install an EGR block off plate to ensure NO exhaust gases or boost leakage can take place via the EGR feed tube. It only takes about 15 minutes to install a block off plate. Again the best long term solution is to get rid of ALL the EGR crap by installing a Week's Elbow Kit from SasquatchParts.com
If you install the Weeks elbow kit, you will need to reflash the ECU to get rid of permanently the DTC's that will be hard set by unplugging and removing the EGR valve and the FCV.

As to ECU programing, you can save yourself the money and use it for other mods, as there are FREE do-it-yourself tunes available on this forum that work really great and are in use by many members of LOST including myself! :rockon:

All that is required is a simple MPPS cable, available on eBay, and a laptop computer. For details on the DIY tunes, see this thread:
viewtopic.php?f=98&t=78418

As others have stated, you can install a little taller tire and it will help with fuel mileage. I believe the consensus is that anything larger than a 245/70/16 will require a small lift to keep front tires from scrubbing at times. I have 245/75/16's, but I have a 2.5 inch lift springs & shocks installed. I can get into the low 30's on fuel mileage on good level roads running these tires, a Stage IV Hot Tune by Yeti tune (one of the FREE ones), a Weeks Elbow kit, and by keeping the little diesel in TC lockup and overdrive (5th gear) as much as possible...

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

I read that thread about the different tunes and thanks a lot for the recommendation on which one to use as there are many of them. I intend to put taller tires with the same width on mine with the same lift (kinda like the ARB Old Man Emu product line). Still deciding on whether to look at a 2.5 or 4 inch lift, wondering what additional problems I will run into with the 4 inch lift in terms of wear on any u-joints etc. OME products seem like the likely choice as I want to eventually incorporate the ARB front bumper and rear bumper, which I know will also effect fuel economy. The motive at this point is to get it as fuel efficient as possible prior to any of those modifications so I know when the additional weight is added it is running optimally.

The EGR kit almost seems like just as critical a modification as the timing belt replacement (Jeep has 117k miles on it and original belt). I had it in mind to perform the timing belt and weeks kit at the same time as both require draining the coolant system. I may reconsider and do them in stages as this is really a project for a retired mechanic messing around with his first Italian diesel. At this point it may only do 4k miles in a year and is not the daily driver. I got a really good deal on it for a little over 4 thousand dollars ... it is a limited version with a set of 5 brand new BfGoodrich All Terrains on it at that! It is a one owner and I suspect the original owner didn't want to fork out the sum of money for a qualified shop to perform the timing belt replacement. Also lowering it value is the paint on the roof and hood which both have awful clearcoat damage (getting Monstalined in black on the hood and roof, saves me time waxing it hah!)

Unsure if you have any insight into whether a 2.5 or 4 inch lift matters in terms of additional reliability or fuel consumption concerns, but with its current running condition at an awful 13 mpg it has to be improved before I even start work on it. I am seriously considering disconnecting the MAF for the time being, I could care less if it turns on the idiot light for engine codes in the time being. With the weeks kit, it sounds like it is safe to assume that the MAF is no longer connected? Or does it still provide sensory feedback to the engine for intake pressures for other reasons with this engine?

Thanks again and Happy Jeepin!

wilco549 · **Posted:** Mon Jul 31, 2017 3:12 pm

Unplug the MAF!. I ran with mine unplugged for over 100k until I removed the EGR components. All it's doing is allowing exhaust crap to infiltrate your intake...which may be some of your problems.

I also highly recommend the YETI DIY tunes....it's really not that complicated if you are handy with a laptop. I think the cable is about $20 and I assure you your fuel mileage (and driving pleasure) will increase. I went from 18-20 mpg to over 25 in the summer....when I'm not torquing it around! :lol:

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

Decided on unplugging the MAF for now...I ran it after I did so until it was fully warmed up and no engine code kicked out! Some things in Chrysler / Jeep electronics almost seem to have gremlins that work against yah, but I'm hoping I have a good one here hah. I cut the fender mud guards away and set it up to bend the pinch welds back as the tires on the truck are 245/75/16s with a stock suspension (no doubt a small contributor to less fuel economy but they are new, might as well use em up.) I read that simply putting some silicon to prevent rust after hitting the pinch welds back is all that is necessary but may cover it with new undercoating. I got a vendor working on beating the price with Sasquatch on the EGR delete kit and hopefully their quote will be affordable enough to pick up next month. Nice to know I can leave the MAF sensor disconnected as I just cleaned up all components as much as possible in the rest of the assembly that would have gotten messed up all over again. I can't imagine how dirtied up the intake is with all I pulled out. At any rate, simply wanted to pass along it kicked no CEL when the MAF was disconnected, odd thing. If that is symptomatic of any other problems let me know so I can investigate but it ran stellar (almost seemed better?) ... time will tell if there is any effect on fuel economy with the MAF sensor disconnected but I am certain replacement of the MAP sensor that is broken will improve it somewhat and is a must.

Happy Jeepin!

TexMech · **Joined:** Fri Jun 30, 2017 10:20 pm **Posts:** 17

Update...CEL finally did go off after cranking it up the third time, reckon I got normal gremilins in the machine to contend with lol. After I rewire the broken water in fuel sensor lead that the previous owner broke with the fuel filter change he performed, will take it out for another spin and see if things run differently.

Happy Jeepin!

APC9199 · **Posted:** Mon Jul 31, 2017 5:09 pm

TexMech wrote:

Update...CEL finally did go off after cranking it up the third time, reckon I got normal gremilins in the machine to contend with lol. After I rewire the broken water in fuel sensor lead that the previous owner broke with the fuel filter change he performed, will take it out for another spin and see if things run differently.

Happy Jeepin!

I wouldn't worry too much about the WIF sensor, unless you're genuinely worried about water in your local fuel supply. It's absence will not throw any codes or affect the performance of the vehicle in any way. I drove my last Jeep for about a year without one and it was fine. I DO recommend replacing it at some point, just don't consider it a primary objective.

WWDiesel · **Posted:** Mon Jul 31, 2017 10:45 pm

TexMech wrote:

I read that thread about the different tunes and thanks a lot for the recommendation on which one to use as there are many of them. I intend to put taller tires with the same width on mine with the same lift (kinda like the ARB Old Man Emu product line). Still deciding on whether to look at a 2.5 or 4 inch lift, wondering what additional problems I will run into with the 4 inch lift in terms of wear on any u-joints etc. OME products seem like the likely choice as I want to eventually incorporate the ARB front bumper and rear bumper, which I know will also effect fuel economy. The motive at this point is to get it as fuel efficient as possible prior to any of those modifications so I know when the additional weight is added it is running optimally. At this point the OME springs are the best choice unless you go with the Jeepin by al's coil over setup which cost a lot more. Bilstein shocks are a good choice to go with the OME springs!

The EGR kit almost seems like just as critical a modification as the timing belt replacement (Jeep has 117k miles on it and original belt). I had it in mind to perform the timing belt and weeks kit at the same time as both require draining the coolant system. I may reconsider and do them in stages as this is really a project for a retired mechanic messing around with his first Italian diesel. At this point it may only do 4k miles in a year and is not the daily driver. EGR delete, block off, or total removal is a must for these vehicles! The Weeks kit is hands down the best option to get rid of all that crap period!

Unsure if you have any insight into whether a 2.5 or 4 inch lift matters in terms of additional reliability or fuel consumption concerns, but with its current running condition at an awful 13 mpg it has to be improved before I even start work on it. I am seriously considering disconnecting the MAF for the time being, I could care less if it turns on the idiot light for engine codes in the time being. With the weeks kit, it sounds like it is safe to assume that the MAF is no longer connected? Or does it still provide sensory feedback to the engine for intake pressures for other reasons with this engine?
4 inches is a lot of lift for these vehicles and should only be used if you plan to add some much bigger tires and do a lot of serious off roading! The 2.5 inch lift will work perfectly with the 245/75/16 tires and will not put near as much strain on the drive line components as a 4 inch lift would subject them to. Also, if you go 4 inches, you will have to go with the Jeepin by Al upper control arms to make things work and get the alignment to work. If you want a little more lift in the front, you can always add some clevis spacers or a top plate to get a little more! :wink:

Thanks again and Happy Jeepin!

Fuel economy - CRD Owners in Texas / San Antonio

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