Bad MPG ... need help checking accuracy of odometer in KJ

Vox Fatalis · **Posted:** Thu Jun 29, 2006 2:32 am

I for one refuse to grow up, getting old sucks...

And there's nothing really in this thread to warrant such a response, IMHO. Some people just misconstrue things I suppose...

That being said... I'm averaging about 23MPG. NOT happy about that... was expecting at least 25. But then again, my CRD is ready to go in for tranny stuff... it loves to freak out trying to get into 5th gear.

I DID get 26MPG on one tank, all freeway driving.

Dutchy · **Posted:** Thu Jun 29, 2006 5:58 am

Check your rear axel if it gets hot, maybe your emergency brake is sticking, hard to notice on an automatic CRD.
Had this happening with my manual CRD, easy to spot with the manual one, but with an autobox the only way to notice it is the fuel consumption, mine went down dramaticly from one moment to the other.

modelaford · **Posted:** Thu Jun 29, 2006 6:58 am

DarbyWalters wrote:

Cowcatcher wrote:

If you take that 27.3 I got on Fathers Day though that would boost me up to 29 MPG. In addition that was starting at 21.8 average on about 180 miles which would have diluted the higher mileage figure. In other words, had I calculated just the Fathers Day tour it likely would have been several MPG higher than the overall mileage and likely would have pushed me above 30 MPG.

I have watched the speedo over the last two weeks and the mph is off 2.5 miles across the board which means the EVIC would be consistent. I do think the miles traveled might be off so in reality we are could be getting a little better mpg than we think. Mileage seems to off by 6.5% or so. That means that at 20 mpg figured by using the odometer could possibly be 21.3 mpg.

Anyone else have a GPS that can verify? Or could someone travel a 10 mile route by marker signs and see if they can see any difference? I would hope that your odometer would read 9.4 miles.

Yup, did just this yesterday. Maybe I should back up. Took the CRD in to the dealer about 3 weeks ago with a list of things to be looked at. One of them was the Speedo, as I thought it was running high. They claimed it was spot on accurate. Well, yesterday my family and I were on the road in two vehicles, and we did some testing. According to BOTH my gps and my wifes car, the jeep is 2.5 mph too high. So, now I have to go figure out how to convince the dealer - again....

Paul

MudTrac · **Posted:** Thu Jun 29, 2006 8:34 am

Ok few things for one who ever it is calling people "morons" should maybe grow up his self.

Second I’m not using a EVIC to calc I am going by the little piece of white paper the big thingy at the gas station spits out when i fill up, i take that number and divide it into the little green number on the dash that says how far I’ve gone.

Now on to the rest of the comments:

Darby - yes I have disconnected the battery since i use to run the engine out. So I’m sure the computer has at least reset once or twice since then. But even when I was a drove a little faster she got better then 20MPG most the time which is what I would expect. I do care for MPG but I wanted the diesel for performance also. And milage vs RPM's I havent been going past 2500 in normal driving, At 70MPH i sit right below 2K. Every once and a while Ill push her to maybe 3500 to pass someone and to clean out the tail a little. I do get some dips and spikes when im around 50MPH sometimes. but mostly when shes cold. I do let her idel for about 2 min before going anywhere and turning her off, the turning off thing is what the turbo timer would help with.

Yes mine was the liberty with the crazy engine issues a few weeks back, but since every person that replied to my post said it’s a freak thing and it’s never done it again, I haven’t taken her in to the dealer.

I want the turbo timer for the obvious reason of letting the turbo cool like the book wants and the boost controller for monitoring the boost. This is not for performance at all. And the Greddy stuff is universal so I don’t know what your issues with that are? There have been plenty of comments on here for the same wants and you flame me for them???

I have legitimate concerns and I love how the "nice friendly LOST group wants to rip me a new one and leave me out cold on it. I have not been " immature" about my questions, I don’t have huge yellow racing stripe or a wing and some spinners on my truck, I helped get the Florida LOST group off and running and anyone of the guys in the south from LA to FL will let you know I’m not a Moron. Thanks for your insight on my problem but if I wanted a flame fest maybe I should have gone to some Honda site.

Oh and I know now that I have the 245's I have been getting accurate milage, I have a GPS in the truck all the time and noticed since I got the MTR's its been right on. So I guess it must have been off when I got it. My speed is correct and milage is the same on the truck and the map.

You know I just saw the axel comment and I do use the break alot when Im on the trail, and I have noticed it has been warm a few times by the rear wheels. But since Im only use to driving manuals I by habit get in the truck and check down the ebrake. Ill check it tonight when I get home and see how hot it is. I dont think it is this but, never know.

DarbyWalters · **Posted:** Thu Jun 29, 2006 9:40 am

MudTrac wrote:

I dont know what it is that Im doing but Im starting to only get like 300miles on a tank and thats 18-19 gallons going back in. which puts me in the 15-16 MPG area!

I really want a boost gauge so i can see whats happening. She has really started to feel laggy and slow. I hardly ever "floor it" unless i have to in traffic. I know you need to get her wound out every once and a while but MPG this low seems really bad, I cry every time some one says they get 400-500 miles a tank.

Has anyone installed an digital boots controller? or a turbo timer yet. Im very tempted to rip my buddys Greddy units out of his car and install them. My F150 4x4 with the 4.6L got better MPG than this....

Is it dealer time for me?

OK, reread your first post...vague..."floor it"...feels slow...and your Title is MPG=Crap. It is hard to take that post seriously. From that to your last post where you check your mileage and confirm it with GPS. Maybe you should have thought out the first post a little better and you would have gotten better responses. I think this thread turned out fine and gave some useful info in the end so it ia all good for me.

I did not knock the Greddy products and have started and answered posts about "Turbo Timers". I think they are a good preventative measure.

Now the comment that a poster made about "moron" IS out of line. It doesn't help anyone to throw that kind of stuff out and just serves to lower the standards that we have come to expect at these forums. Try to keep your responses civil. If you go to almost any other forum...I checked out a Hummer 3 and the Xterra forums and almost every post has internet battles going on. It makes the thread useless by the time it is over. Dont' want that to happen here.

MudTrac · **Posted:** Thu Jun 29, 2006 11:11 am

Sorry for the confusion, but this has been an on-going post, I’ve made comments before, this was more of a summary of problems and a tell all of what I was thinking, Im sure those who might not have seen the other posts might have thought of it as "vague".

Enough belly aching, no hard feeling, I just wanted some answers and maybe a few hints to look for, fuel issues are killer in any car, hard to pin-point, due to human error and the hundred of things in the car that could cause this. Right now on the last tank I’m logging mileage on the GPS, and speed. Also the type of driving, what roads, and weather (hot wet, etc). I’m going to if nothing else, present it to the dealer and get them to do something about it. I also have samples of the fuel I used. Hope this clears up some prior thoughts to my intelligence... I’m going to run a test of 3 fill ups and do the math off that, same station and same pump, however I’m sure it won’t be the same batch of fuel, but I’m most certain it has nothing to do with bad fuel.

Any more good input would be greatly accepted.

DarbyWalters · **Posted:** Thu Jun 29, 2006 11:29 am

Maybe we could all do a "raod trip". Salinas, Kansas claims to the heatland of the USA (48 states anyway). We could all drive there and compare mileage. That should be a big enough cross section of real world conditions.

You are right...I had not seen any of your others posts. I just recently purchased a CRD and had not visited this forum section until a few weeks ago.

Oh yeah, SP DIesl Performance says they have a Turbo Timer that works with the Jeep CRD and isn't affected by the Sentry Key.

oldnavy · **Posted:** Thu Jun 29, 2006 12:23 pm

retmil46 wrote:

I know it's been hashed over before, but from what I've seen, the biggest variable in MPG is the quality of fuel in your area. I've seen mine go from 30 mpg on one tank to 22 mpg on the next and then back to 30 mpg on the third, driving from NC to TX, just because I was in a different area of the country, having to fill up with a different brand of fuel from a different refinery each time.

With the current lax specs for what qualifies as diesel fuel, it's nothing more than a crapshoot as to what you're getting for cetane level, cleanliness, water content, etc., unless you actually bother :wink:

to take a sample and have it analyzed for each station in your area to see which one has the best fuel.

This Moron is with stupid above about the fuel thing.

Drove the CRD to MI last month for a diesel GTG and averaged 32 mpg or 33 mpg on my fuel, but coming back the same route and driving style the mileage was down and the only difference was fuel.

Shucks coming back was all down hill from being UP north in MI, should have got better running down hill like I was coming home. :lol:

MudTrac · **Posted:** Thu Jun 29, 2006 12:39 pm

DarbyWalters wrote:

Maybe we could all do a "raod trip". Salinas, Kansas

I think Its Salina Kansas , and Id be up for a Diesel GTG there, only like 20 hours for me to drive.

I didnt know that SP had a turbo timer out right now, I havent been to their site in a month or so. I was thinking about getting the SP module though, I know it wont help a huge amount with MPG but it will with tug... But then we'd be back in the poor fuel economy LOL.

vtdog · **Joined:** Fri Sep 30, 2005 11:27 am **Posts:** 640

The problem with driving 55-60mph to get the best mileage is that the increase in mpg comes from the fact that the jeep is being pushed from behind by the semi that has squashed the jeep's rear. So, any saving is diesel is offset by having to by new vehicle

Reggie · **Posted:** Thu Jun 29, 2006 1:22 pm

oldnavy wrote:

retmil46 wrote:

I know it's been hashed over before, but from what I've seen, the biggest variable in MPG is the quality of fuel in your area. I've seen mine go from 30 mpg on one tank to 22 mpg on the next and then back to 30 mpg on the third, driving from NC to TX, just because I was in a different area of the country, having to fill up with a different brand of fuel from a different refinery each time.

With the current lax specs for what qualifies as diesel fuel, it's nothing more than a crapshoot as to what you're getting for cetane level, cleanliness, water content, etc., unless you actually bother :wink:

to take a sample and have it analyzed for each station in your area to see which one has the best fuel.

This Moron is with stupid above about the fuel thing.

Drove the CRD to MI last month for a diesel GTG and averaged 32 mpg or 33 mpg on my fuel, but coming back the same route and driving style the mileage was down and the only difference was fuel.

Shucks coming back was all down hill from being UP north in MI, should have got better running down hill like I was coming home. :lol:

I've had my fuel checked and it has a cetane value of 53 and I still can't break 21mpg. I would really like to know what can be "tweaked" on the engine to give me better fuel economy. Tires are at 38psi, air filter and fuel filter have been changed, motor oil is fresh, ECM and TCM were flashed due to the latest TSB, what else can it be? There seems to be a fair amount of CRD owners that are getting crappy fuel economy. This is the sixth diesel I've owned and the only one that has gotten relatively poor fuel economy. I'm thinking of modifying the crank position sensor like they do for the Dodge CTD to advance the injection timing. There has got to be a mechanical reason why a lot of us are getting crappy fuel economy other than the standard driver error or porr fuel economy.

oldnavy · **Posted:** Thu Jun 29, 2006 2:41 pm

MudTrac wrote:

DarbyWalters wrote:

Maybe we could all do a "raod trip". Salinas, Kansas

I think Its Salina Kansas , and Id be up for a Diesel GTG there, only like 20 hours for me to drive.

I didnt know that SP had a turbo timer out right now, I havent been to their site in a month or so. I was thinking about getting the SP module though, I know it wont help a huge amount with MPG but it will with tug... But then we'd be back in the poor fuel economy LOL.

Hey there is the GTG here at my place in Oct that some could use for MPG testing and then beat up on the VW TDI driver's. That should be lots of fun and I could do video & pic's for posting. :wink:

MudTrac · **Posted:** Thu Jun 29, 2006 4:52 pm

The only time Ive been to MO was to Branson, had a good time.

I agree there has to be something, mechanicaly wrong. I would be more than happy to lend her out and have someone drive her for a few hundred miles and see if they notice anything. To bad there isnt anyone in the south east that could meet up.

Joe Romas · **Posted:** Thu Jun 29, 2006 5:09 pm

naturist wrote:

I've only 13,000 miles worth of experience with the CRD Libby, and know much more about the VW TDIs, so feel free to take my comments with a grain of salt.

I do know that the VWs can show much lower mileage if the injection timing gets out of spec, typically retarded, and I wonder if this might be you guys' problem. It is adjustable, but requires special tools and experience to do, but it should be possible for the dealer to determine what the timing is. Experience on the VWs is that you want the timing set toward the advanced side of the allowable range.

I've also owned a bunch of VW diesels and 2 TDI's that I got new. Both didn't shine in mileage till about 20k miles. As far as the basic timing goes, the older tdi's with the pumps were adjustable. Not anymore with the PD's (2003 as I recall could be wrong). Also the CRD's are Common Rail Diesel and it's totally computer controled.

My CRD still is under 1k miles :oops:

but I'm averaging right at 20 with all in town and short trips :wink:

That's double my 99 4.0L cherokee so i'm happy but will expect more as time goes on. Also I think the engine management is part of the problem. My transmission at times is really confused :shock:

retmil46 · **Posted:** Fri Jun 30, 2006 12:53 am

Reggie wrote:

oldnavy wrote:

retmil46 wrote:

I know it's been hashed over before, but from what I've seen, the biggest variable in MPG is the quality of fuel in your area. I've seen mine go from 30 mpg on one tank to 22 mpg on the next and then back to 30 mpg on the third, driving from NC to TX, just because I was in a different area of the country, having to fill up with a different brand of fuel from a different refinery each time.

With the current lax specs for what qualifies as diesel fuel, it's nothing more than a crapshoot as to what you're getting for cetane level, cleanliness, water content, etc., unless you actually bother :wink:

to take a sample and have it analyzed for each station in your area to see which one has the best fuel.

This Moron is with stupid above about the fuel thing.

Drove the CRD to MI last month for a diesel GTG and averaged 32 mpg or 33 mpg on my fuel, but coming back the same route and driving style the mileage was down and the only difference was fuel.

Shucks coming back was all down hill from being UP north in MI, should have got better running down hill like I was coming home. :lol:

I've had my fuel checked and it has a cetane value of 53 and I still can't break 21mpg. I would really like to know what can be "tweaked" on the engine to give me better fuel economy. Tires are at 38psi, air filter and fuel filter have been changed, motor oil is fresh, ECM and TCM were flashed due to the latest TSB, what else can it be? There seems to be a fair amount of CRD owners that are getting crappy fuel economy. This is the sixth diesel I've owned and the only one that has gotten relatively poor fuel economy. I'm thinking of modifying the crank position sensor like they do for the Dodge CTD to advance the injection timing. There has got to be a mechanical reason why a lot of us are getting crappy fuel economy other than the standard driver error or porr fuel economy.

Sounds like you've already eliminated most if not all of the normal basic causes, leaving something mechanical/electrical/electronic. Yeah, I know, that doesn't really narrow it down.

Gawd, 53 cetane! I'd be down on my knees kissing the station owner's ring fingers if I could get fuel that good around here. If you're only getting 21 mpg with that, there definitely is something fubar.

Special Agent · **Posted:** Fri Jun 30, 2006 1:57 am

I'm driving mostly city HILLY miles (West Seattle area), about 75% of the time. The rest is freeway at 65mph.

My rpms are usually around 2000-2500, I try to keep them low and not speed around town.

I keep it in Full-Time 4X4, only noticed about a 1mpg gain or less when going back to 2x4...

I also use about b75 biodiesel, I get maybe one or two mpg better on premium diesel.

And I'm averaging 17.5-18.5mpg.

If I put it in 2x4 and drive w/ premium dino, I can get around 19-20.

This seems low to me.

My CRD has a bit over 3K miles on it, 2006 model

oldnavy · **Posted:** Fri Jun 30, 2006 7:11 am

Reggie wrote:

I've had my fuel checked and it has a cetane value of 53 and I still can't break 21mpg. I would really like to know what can be "tweaked" on the engine to give me better fuel economy. Tires are at 38psi, air filter and fuel filter have been changed, motor oil is fresh, ECM and TCM were flashed due to the latest TSB, what else can it be? There seems to be a fair amount of CRD owners that are getting crappy fuel economy. This is the sixth diesel I've owned and the only one that has gotten relatively poor fuel economy. I'm thinking of modifying the crank position sensor like they do for the Dodge CTD to advance the injection timing. There has got to be a mechanical reason why a lot of us are getting crappy fuel economy other than the standard driver error or porr fuel economy.

By your own statement above you have done every thing correctly, and are not driving it all the time with foot to floor or towing a 5,000 lb trailer. About the only thing left to have that kind of effect on fuel mileage is IP timing, I am betting if your IP timing was checked it would be way off. I would check into how to "properly" change the IP timing and give it a try, and it sounds like you are on the right track and need a "hammer mod" like is done on ocassions to VW TDI's to get them set up properly. Those VW guys have the VAG-COM softeware to be able to fine tune the IP timing amoung everything elese that it can do for the VW cars, too bad we don't have that kind of software available.

gsbrockman · **Posted:** Fri Jun 30, 2006 8:08 am

oldnavy wrote:

About the only thing left to have that kind of effect on fuel mileage is IP timing, I am betting if your IP timing was checked it would be way off. I would check into how to "properly" change the IP timing and give it a try,

Old Navy........
To my knowledge, the CP3's used in our CRD's, the 3rd GEN HPCR Cummins Turbo Diesels, and the GM/Duramax's require no injector pump timing, as the CP3 simply creates pressure to a common rail that supplies electronically / computer controlled fuel injectors.

I've read over on the TDR site a few articles some time ago regarding modded CP3's (one company can tweak the CP3 for a CTD and get ya 88 rwhp) and the same question was brought up.

Greg

oldnavy · **Posted:** Fri Jun 30, 2006 8:19 am

gsbrockman wrote:

oldnavy wrote:

About the only thing left to have that kind of effect on fuel mileage is IP timing, I am betting if your IP timing was checked it would be way off. I would check into how to "properly" change the IP timing and give it a try,

Old Navy........
To my knowledge, the CP3's used in our CRD's, the 3rd GEN HPCR Cummins Turbo Diesels, and the GM/Duramax's require no injector pump timing, as the CP3 simply creates pressure to a common rail that supplies electronically / computer controlled fuel injectors.

I've read over on the TDR site a few articles some time ago regarding modded CP3's (one company can tweak the CP3 for a CTD and get ya 88 rwhp) and the same question was brought up.

Greg

Ok, does that mean that it is most likely a programming problem then and not a simple mechanical problem? Something has to be timing the injection and telling injectors how long the spray duration last, is that the CP3's (not sure of the meaning of CP3) and can it be changed somehow?

Reggie · **Posted:** Fri Jun 30, 2006 8:20 am

gsbrockman wrote:

oldnavy wrote:

About the only thing left to have that kind of effect on fuel mileage is IP timing, I am betting if your IP timing was checked it would be way off. I would check into how to "properly" change the IP timing and give it a try,

Old Navy........
To my knowledge, the CP3's used in our CRD's, the 3rd GEN HPCR Cummins Turbo Diesels, and the GM/Duramax's require no injector pump timing, as the CP3 simply creates pressure to a common rail that supplies electronically / computer controlled fuel injectors.

I've read over on the TDR site a few articles some time ago regarding modded CP3's (one company can tweak the CP3 for a CTD and get ya 88 rwhp) and the same question was brought up.

Greg

That was my understanding also. There is one company that modified the crank position sensor so that it would adavnce the timing by about 2 degrees by changing the position of the sensor itself. I was thinking of doing something along these lines.

Bad MPG ... need help checking accuracy of odometer in KJ

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