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Sudden MPG Drop

41K views 32 replies 16 participants last post by  dravas 
#1 ·
Previously, I've stated that I wasn't completely happy with my fuel mileage. To date, my best mileage has been 25 MPG highway. I believe part of that is due to the speed limits in this part of TX being mostly 75 & 80 MPH. I now have about 4700 miles on my Lariat Long Horn 4X2 and my MPG has suddenly dropped. I was getting a solid 22-23 MPG for daily commuting. Now, my MPG is down to 18-19 MPG for the same drive. What could be causing this? Nothing is changed, no towing, no EVIC warnings, nothing. I've got that gut feeling I have a lemon with a nice helping of douche nozzle customer service. The selling dealer wont return my calls or even book a service appointment to look into it. Have I made a $50,000 mistake by going with this Ecodiesel vs. the reliable and proven VW/Audi diesel I was originally looking at? ****, I think I've heard of less issues with the Chevy Cruze diesel!
 
#3 ·
I am surprised by all the people mentioning bad dealers. I have 4 within about 45 miles of me and if one was bad I would drive to the next. Maybe others are in more remote parts of the country but I would call Chrysler customer service to report them and get them involved if thats the case
 
#5 ·
Well, I thought I might have a fuel problem, so I went to another station and filled up there & there was no difference whatsoever. I'm not aware of anything called "winter diesel" in this part of the country. I use the remote start on cooler mornings, but usually I don't let the truck idle more than 5 minutes. I added a considerable amount of air to my tires Saturday, so I will see if that makes any difference at all this week...
 
#7 ·
Good point - I look at the EVIC instant reading and then the average. Both are very close to each other. Maybe I should just turn that off for a while & do a manual calculation per tank & see if its different.


This does raise another question. Why would the EVIC suddenly start reading erroneously? Are they prone to that?
 
#8 ·
Hershey,
When I bought my truck in Aug, I was getting about 27-28 MPG (US Gallon, all highway driving). Since then my milage has been slowly dropping as well. I now have just passed the 10,000 KM mark and my EVIC is showing 18.2 MPG (I do hand calc on every fill-up, but I still have 1/4 tank of fuel left, so I dont know if the EVIC is reading inaccuratly). I have not modded the truck in any way. it still has that rediculus nose dive rake and nothing added for winter weight, no fuel additives except for the winterized diesel at the pump, if they have even started adding it yet.
Now, I did change my rims to 17" with the tire size that matches my old tires to -3% in size (so not much difference) for a winter tire. That being a heavier tread compaired to stock I guess. I do know it is colder now (coldest so far was only -9C), and I gave it few minutes of warm-up before driving, all highway driving to work.
SO... I called my dealer about it today and they seem concerned about it. When I told the service rep what I was getting, he asked about driving habbits and where I get my fuel and suggested trying a different fuel supplier for comparison since I am due for a fill-up before I bring it in. With all these questions aside, he said that is still getting lower then expected milage and he wants the mechanics to have a look. What he said that they would do is: check all fluids and filters to start, then check and see if all software is up to date, also check engine diaognostic (I'm not sure what that entails, but I guess to check compression and timing?) and of course visual inspections for anything damaged or wearing early. oh yea, he said it will be under warrenty because of the nature of the inspection.
 
#9 ·
update: Just got a call from the service dep, TWO new updates or "drivability flashes" installed, diagnostic showed everything else in perfect order. I donr know how the flash updates will change it to much, but I will report any MPG gains.
 
#10 ·
A few things...


Diesel Engine (and gas for that matter) like it warm. They run better (more efficiently) when they are warm...so short trips in cooler weather will give you decreased mpg. Might think about covering the front grill (diesel blanket) to up mpg. You could even try cardboard to test the theory by limiting the cold air that hits the radiator.


Diesel fuel ignites under pressure/heat. You might need to add some kind of fuel additive to increase the Cetane Level of your diesel fuel. In Europe, their fuels have a better Cetane Rating. Think of it as "reverse octane"...in a gas engine you want to up the octane (to a point) to fight detonation. In a diesel, when you increase the Cetane rating...the diesel fuel detonates easier and burns more efficiently.


You can even block off your cold air intake for a bit more heat and improved mpg in the winter.


I would also contact www.GreenDieselEngineering.com and see if they have any upgrades for the stock computer. These guys know their stuff and are very familiar with these VM/Fiat Diesels.
 
#13 ·
Odds are better than good that "winter fuel" is being sold where you live if you live anywhere near where the temp "might" get below 30* or so.
you will see a decrease in MPG with winterized fuel. Beats the other option...jelled fuel.
Never trust the EVIC. Hand calculate then compare the 2 numbers. As I said on another thread in the big Rams 2500/3500 diesels we call the lie-o-meters for a reason. Also, a diesel is a negative heat loss generator. Remote starting and let idle when cold will kill the mpg. When it's cold out try this. Start the truck, drive it to get it warm/hot, park and let idle for 5 minutes. Bet the temp actually drops compared to when you were driving. ie. negative heat loss generator. Diesels make heat under a load/when working. Not idling. Look up "wet stack(ing)". NOT good. and it does apply to ALL diesels.
 
#14 ·
I have notice a 3mpg drop in my around town driving since hitting 4500 miles on the odometer as well. Purchased my 4x4 Larimee on 11 August, on 17 November the starter went up. They hgad it in the shop from Tuesday through Friday for a starter, went in on Friday and they said might need to keep it until the next Monday until I complained and the owner told the service department to get a starter off from a new truck. They changed it and it still would not start, later that evening they discovered it was "a corroded cable from the alternator." How a 12 week old vehicle has a corroded cable is beyond me....but I noticed when it would not start that it was throwing sparks under the hood when it did try to crank. The dash was reading "Service 4 wheel drive system" when it would not start. These new electronic systems are very questionable in their reliability in my mind.
 
#15 ·
I'm going to schedule a service appointment. I'm cringing because of all the stuff I've read on here. I noticed my tach was reading higher than it should at times when the EVIC was showing poor fuel mileage. I'm thinking the transmission is doing something funky, but I'm not getting any CEL or malfunction of any kind. I'm hoping they get me another truck while they play games with mine, but who knows...


Oh, one more thing - here in this part of TX, there is no such thing as "winter fuel". Its the same year round.
 
#16 ·
You know, when we use the defroster in cold weather it fires up the compressor the same as if we were using the the air conditioning. Gotta keep that thing off unless the window is fogged up. You can tell cause the light comes on on the hvac control knob (depending on which system you have).

That could affect fuel economy a bit.

Just another item you probably don't use in Texas.
 
#17 ·
Hey Zoomie,
I used the A/C constantly when I bought this in Aug. Now that its cooler, I'm not running the A/C half as much & I think I've used my defroster twice...maybe. This morning a did the remote start as I was getting ready & the cab smelled like diesel exhaust, but no smell outside! I'm getting the feeling that this truck has a bunch of crap wrong. I'm getting 20.5 highway now. Still no warnings...is it going to surprise me or what? I would dump this at the stealership today, but I really need it this weekend. Any pointers on getting a truck for a loaner?
 
#18 ·
20.5 average is nothing to be upset about in a half ton truck. My dad's hemi ram ( & he drives like an old guy ) is in the 14 mpg range. Slight variances in driving play huge in the per tank average. My tank prior to my last was 19.7 average hand calc. That was alot of city driving though. Last fill was 23.3....mixed hwy / city hand calc. And I'm sure they are running the winter blend around this part of the country.

Hershey, that 20.5 per evic?
 
#19 ·
To add to it....my last fill I reset my display economy as I always do. From the station to home is basically all highway. Pulled in my shop and shut her down @ 28.4. Next day just during the warm up I was down to 20.7. Point is, the longer you wait to reset your fuel economy display the less it drops due to a longer average. For instance that decrease wouldn't have been as dramatic if I had never reset it from new. But since I just reset it 12 miles prior to shutting it off, that is the only comparison it has to go by for an "average". The only accurate way to do this is hand calc when you fill up. That will give you the truth.
 
#20 · (Edited)
agreed. Remote start-0- MPG. colder outside temps uses more fuel until warmed up. EVIC=lie-o-meter. feel good gauge (when you see super high MPG's.) As you said leave the EVIC ALONE/don't believe it. Hand calc only at fill up and NEVER reset the EVIC. It will get closer the longer/larger the data sample is. anything else is just a guess be it the EVIC or the owner.So far as the exhaust smell IF there are no leaks in the system and the remote start is used. I'll bet the heater was running wide open. Unless it was on Recirc. the heater draws air from outside the truck and diesel exhaust is more noticeable (pungent) than gasser exhaust. Especially when it's cold. Happens to me on the VERY few occasions I let my truck "warm up" in the winter.
 
#21 ·
As soon as I purchased this truck I drove it 200+ miles home - all highway. The EVIC never went above 25 mpg. I've since made the same trip several times & while using cruise control, I've NEVER exceeded 25 mpg highway. Now, I have raw diesel exhaust entering the cab & it's drinking def like water. The mileage came up a little after I put a touch more nitrogen in my tires to 41 psi (pressure was all over the place previously). The local dealer can't look at it until Jan 2015 & I'm waiting on a callback from one that's 200 miles away to see if they can do it sooner.

I opened up a case with Chrysler also. In my opinion, with just 5000 miles, these trucks are rolling lemons. I've seen FAR too many Ecodiesel owners with the same issues at similar miles. Sorry, I said it, but that's using logic & not jumping to conclusions. I've never seen a dealer tell customers they had to wait 30+days just to get into service & then wait weeks for parts after diagnosis! To me, this is insane & I regret this purchase. I've had my share of lemons before, but never waited for service & ALWAYS was given a vehicle to drive while any service was being performed (outside of routine maintenance.
 
#23 ·
Hershey,


Not sure why your dealer is so bad. That dealer is a disgrace.


Also not sure how you meet so many Eco. owners that have so many problems. I have met a few but none had any problems. I read these forums too. Read all kinds of things. If I did not read, my personal experiences would tell me these engine packages are perfect.


As for fuel mileage, I have an extra fuel tank. Recently did a hand calculation after about 400 miles of towing a loaded 8ft. open trailer and then another 500 more miles of running around. I do not remember the exact mileage or fuel consumption but clearly remember that for the over 900 miles my EVIC read 24.1 and my hand calculation was 24.2mpg. Made sure I topped both tanks off also.


Another memory tells me the fuel cost for those 900+ miles was around $74. Think I paid $3.14 at Walmart so it was just around 24 gallons also.


While you seem seriously bummed out I and everyone I ever personally spoke with that has one, flat out LOVES the engine package.


Now as for those darn electronic, computer control modules...they scare me too but ALL the new vehicles have that crap.
 
#24 ·
hand calc'ed at 17.8 MPG today... mixed driving. Dealership still cant find any issues that could be affecting this. I am trying to drive as conservative as possible, and cant believe these numbers. I paid for fuel economy and I am not getting it, still has the terrible looking stock rake, the only change was from 20 wheels to 17 wheels with blizzack tires at the same diameter.
 
#26 ·
I don't think 17.8 is great, but I hand calculated 19.8 today on my last tank. That was 337 miles of mostly city driving. It actually say probably 10% highway....the rest city and county roads. In my last truck this time of year, I'd be somewhere in the 13 range, maybe close to 14. Heck, it's winter.....all of the variables have a direct link to the decreased fuel economy. I'm not gonna get wound up about my fuel mileage. Now that being said, next spring if I'm not back to my 23 average maybe I'll start looking for answers. I know my aftermarket rim/ tire combo hurt me slightly.

As far as the rake goes, I don't think you have a leg to complain on....you bought the truck with it. If it bothers you, put a leveling kit on it, make it look more aggressive and lose another mile or so a gallon.
 
#27 ·
My truck is now in the shop for an undetermined amount of time. I was given another Ram 1500 to drive & this one has a Hemi. I was real skeptical of the mileage they claim the Hemi gets on the highway. Well guess what? The sticker is RIGHT! This thing has tons of power, sounds great and...it gets 20-21 mpg while running 75-80 mph! My Ecodiesel was barely getting that! Ram has a lot of explaining to do on their mileage claims for this Ecodiesel!
 
#29 ·
Not bragging, but that would be a BIG step down. We have decided that if they can't get all the gremlins fixed in a reasonable time, we are completely done with anything Ram ever again. I'm still in shock how some dealers are backlogged for 4 months on service! How does that happen? Why would Ram want that kind of a dealer in their franchise network? I do know that during Chrysler's bankruptcy, many, many very good, but small dealers were kicked to the curb in favor of mega dealers. I think that was a very bad move, as mega dealers only care about profit and really don't give a crap about their customer's needs.
 
#31 ·
I am having the same issues, I was getting 24,25 all summer. My milage has now droped to 16-18 no ware close to what is claimed. I had a case manager for several months through chrysler, they closed my case with no reslove. I tried trading my eco and one dealer did not even want it on his lot due to all the problems they have been hearing about them. The dealer I baught it from has been no help and offered me 33,000 on a trade 6 months after I purchesed the vehicle which listed at 49,000. These trucks are garbage and with the poor costumer service I will nver buy another Dodge product again.
 
#33 ·
With city I averaging 21-19 (depends on my lead foot) - this is with stop light to stop light Houston westimer traffic.

When I go camping - I can get my mpg up to 26 (usually hauling a trailer when I go camping). My old manual transmission 2002 F-150 V6 got at best 18 empty hwy, 13-15 city, 9-13 bed loaded,, 5-11 heavy trailer

The truck is rated for 19-28 city for a 4x4 and that's what I am getting. If you dont tow get a Ford Eco Boost they are faster get about the same mileage, but if you slap a trailer on the back dont expect your mileage to be higher than 15.

I had the Dodge electrical gremlins but I knew that going in.
 
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