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Poor fuel mileage

51K views 62 replies 43 participants last post by  honor1 
#1 ·
Anyone had any problems with the mileage? I've had gradual reduction in mileage for awhile now. I took the car to the San Antonio dealership and had it's first service done and told them about the mileage. They gave it it's first new car service although I only had 4500 miles on it. They claimed they couldn't find anything wrong. After two more tanks I'm still only getting about 30 to 32 mpg. Really ticks me off.

We're located on the gulf coast of Texas meaning it's about a 3 hour drive so it's not that easy to take it back. I'm beginning to think I made a mistake purchasing this car.

Anyone have any other ideas what to look for. Doesn't seem to do any good to take it to the dealer so thought I'd maybe do a little research myself.
 
#2 ·
We will need more info, such as:

Average length of trip
Highway or in-town
If highway how fast you drive
Type of fuel, straight gas or gas + ethanol
Octane of gas
How heavy is you foot?

From personal experience (we have 2 smarts) we did not reach max mpg's until over 10k miles. Also depending on where I purchase fuel (as in I know they cheat on octane) I can vary from 42mpg-47mpg (90% highway).
 
#5 · (Edited)
Mileage may improve a bit as it breaks in more, but there's always the usual stuff to check/try:

1. Are your driving habits/conditions to blame? City driving, high speeds, lead foot, mountain climbing, towing, etc.
2. Poor quality and/or high ethanol content fuel and/or winter blend fuel will take a toll on your mileage. Maybe try a different brand/station for a couple tanks?
3. Air filter clogged (dusty conditions?) or other restriction in the intake system? I had a mouse build a nest in my previous Civic's airbox...
4. Tires properly inflated? Check them with a gauge, not just visual inspection or waiting for TPMS light to come on...
5. Mechanical drag? Can you easily move the car by pushing it (on level ground) when it's in neutral and the parking brake is off? Otherwise, a brake may be dragging.
6. Do you run the defrost or A/C constantly/frequently (both use the compressor)?
7. Exhaust obstruction?

Lastly, are you keeping track of your actual fuel usage (gallons and miles) so you can precisely see what your average mileage is over time? You can see a seemingly "bad" tank every now and then due to pump shutoff error. I went from 52 MPG on one tank to 32 MPG on the next tank with the same type of driving due to pump shutoff variation. Those two tanks when averaged, however, are close to my overall average. Try Fuelly.com, if you don't have something else you are using already.

 
#9 ·
3 of us guys drove a guy nuts at work when he got a new VW he checked his MPG all the time. And would Bragg about it to us. What he did not know is each day one of us would put 3-4 gallons into his gastank when he left it in the parking lot. We did this for about a month until he went in for service. We stopped doing it and he was on the phone all the time ranting and raving at the dealer for changing something on his car or taking off the secret Canadian carburetor.... We never did tell him what we did.............. Was fun just watching him come unglued the madder he got the more we enjoyed it. Sometimes revenge is sweet. He was the same guy that liked to steal everyones lunch from the icebox at work
 
#10 ·
3 of us guys drove a guy nuts at work when he got a new VW he checked his MPG all the time. And would Bragg about it to us. What he did not know is each day one of us would put 3-4 gallons into his gastank when he left it in the parking lot. We did this for about a month until he went in for service. We stopped doing it and he was on the phone all the time ranting and raving at the dealer for changing something on his car or taking off the secret Canadian carburetor.... We never did tell him what we did.............. Was fun just watching him come unglued the madder he got the more we enjoyed it. Sometimes revenge is sweet. He was the same guy that liked to steal everyones lunch from the icebox at work


Now all we need is a prank joke thread! :p
 
#14 · (Edited)
Yep, no mystery here. Just making a point.

But, Florida is far from the only place that gets hot in Summer. I once spent a Summer outside of Minneapolis ... it was just as hot as here. Granted, it doesn't last nine months, but I wouldn't want an un-air conditioned car in the temperatures I experienced there.

I understand the blame goes to Winter mix gasoline. In my personal experience though, the use of Air Conditioning is a greater factor, as witnessed by the graph I posted. But, who knows? Maybe the Winter blend isn't used in Dixie????
 
#15 ·
I have a similar issue. I have put on the same size tires on the front and back, and anticipated a slight gas consupmtion increase, but I used to get 43 to 44 on the highway, now I get 37-38. Around town it is around 31. Not what it should be for so light a car and small engine. I took it to the dealer for the 10K checkup (at 8500) and was told everything looked good and not issues. Not sure what to do now, but definately puts a blush on my positive attitude about Smart fuel enonomy.
 
#18 ·
I think if you're talking about low MPG then you probably have the car. Seems to me that we have salesman on the forum, always preaching about how great a car it is. I get it I bought it. Now with that said I'm not even getting 30mpg at this time with my smart. One of the big reasons I bought it was for the mileage, now when my friends ask me why I bought it and I say the top reason was mileage. Then they ask what do you get and I say 29.6 mpg. I might as well lie about it, its just easier. If I have to have 15 perfect combinations of weather and driving habits to get the Advertised mpg. wish I'd known that. I drive 28 miles to work one way 5 miles on 2 lane roads the rest on the freeway at 65-70 mph, and yes the defrost is on its winter. If I didnt use it I couldn't see where I was going. Yea maybe it's the way I drive, I don't know. I think what we are trying to convey is frustration.
 
#19 ·
I drive 28 miles to work one way 5 miles on 2 lane roads the rest on the freeway at 65-70 mph, and yes the defrost is on its winter. If I didnt use it I couldn't see where I was going. Yea maybe it's the way I drive, I don't know. I think what we are trying to convey is frustration.
I'd say that it's most likely human factors accounting for this.

1. Many people (even on this forum) lie or otherwise misrepresent their milage. If you go by fuelly, the smart seems to get about 37 mpg on average (year-round). People who don't keep careful track of their milage can't really talk, esp'ly on a tank-by-tank basis, since there is so much room for error on a tiny tank if the pump shuts off too early/late.
2. Your commute should be producing better milage, I'd think, but you are running in winter with the defrost (and heat?) on. Driving at that speed (you claim 65-70, but I'd guess faster for those low mpg's), you're not going to see great milage.
3. People say that the winter blend of gasoline makes a difference. So do winter-related factors like wet roads and wind. If you are driving in those conditions, I'd imagine that you'd rack up some bad milage. I see a huge drop in mpg's over the winter months.

So you could try keeping track on fuelly (or by hand, as I did until I put all the info into fuelly), to see what kind of milage you're getting consistently. And you could try driving slower, conditions permitting. And are you driving with at least 91 octane gas? I use 93.

I wish I could offer more advice.

 
#21 ·
Dale C., are you sure you have 190's or are they 195's? The 195x50's are the same diameter as the stock Conti's, I don't think it will change your odometer. What does change is the weight of the tires and the rolling resistance that could lower your MPG. I have the 195x55x15 Blizzack snows on the rear of mine this winter and have seen my MPG decrease by 5-6 mpg.
 
#22 ·
Your right, my big fingers. My tires are 195X50X15 Yokohama "S" directionals. I have just seen a large drop in MPG since having them installed. I usually drive 70 MPH on a flat freeway when going to Salt Lake. My other driving is to work on city streets, about 6 miles each way per day. Months back I used to see 40+ with no problems, then it began to drop and now is down to the mid 30's.
 
#32 ·
Too answer some of the questions. I do not drive with a heavy foot. Most of the driving is in town, but it's a small town. No heavy traffic. I do use premium fuel. I assume it has ethanol, like most do. And I'm aware that ethanol can reduce mileage, but I didn't expect it to reduce it that much. We are along the gulf coast in Texas. So no snow or weird driving conditions, it's flat as a pancake down here. One thing though, the car is a 2009 and I have less then 5,000 miles on it. I thought maybe it's just because it's not broken in yet. However, I was getting up to 40 mpg average. i.e., mostly city driving, some highway during this period.

I keep thinking it's something mechanical, but the shop said they couldn't find anything wrong. I was hoping someone else had some ideas in this area.

Thanks for the replies.
 
#33 ·
I live in san antonio and have only been to the dealer once for service under warranty. After that I started going to the round rock dealer. The people there are great. I always deal with Mike in the service dept. They tell me up front how much it will be, how long it will take and have always been very accurate. Plus austin has the cars to go program. I think that has made them more knowledgeable.
 
#36 ·
Hey b2fortwo. I also live on the Texas gulf coast and just started having the same problem. Have a 2009 with 25K, and up until a couple of months ago was getting about 40 mpg, and recently it has been steadly decreasing and now at about 35 or so. I also have an Ultra Gauge and it also shows a decrease, but I think it has a memory of past preformance and is averaging, but also going down. I am not a hard driver, tires properly inflated, clean air filter, clean synthetic oil, new oil filter, use only premium fuel, and do all of the right things. Can't figure it out. I may try to change plugs soon, but that is my last resort. Strange!!!!
 
#37 ·
I moved from CT to FL in March. In CT I was averaging over 39mpg. Once I got to FL my average dropped to 35. I think it must be the fuel, but do not know how that works. I have tried changing brands will little difference in the results. Perhaps they put more of the corn stuff in the fuel here.
 
#38 · (Edited)
More corn juice (ethanol) could be to blame, but the first thing I would expect would be more A/C usage and possibly worse traffic conditions. If you do try different brands, you'll have to run something like 3 tanks from each brand and average the results for a better comparison. There is too much discrepancy from tank to tank due to pump shutoff variance for a good analysis on a single tank. :)
 
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