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We have an 07 Sante Fe with the V6 and love it, except for the gas mileage. We have had it in multiple times and the dealer keeps telling me there is nothing wrong with Sante. We have had it for a year, and I keep track of every tank of gas that I run through it. With mostly in town driving, we get 12-13. That went down to 10 this winter. The dealer suggested that I run injector cleaner in it. When I do, I get bump of 3 mpg for that tank, then the mileage takes a dump back to 10-11. I get that kind of mileage with my 1996 Chevy pickup, I don't expect to get that kind of mileage with my wife's Sante. Since running injector cleaner in the tank increases my mileage by 3, I think it's an injector issue, but the dealer tells me it's not. Air cleaner is good, tire pressure is good ... Any ideas? Am I wrong, or does this sound like an injector issue?
Thanks in advance for your help.
 

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We have an 07 Sante Fe with the V6 and love it, except for the gas mileage. We have had it in multiple times and the dealer keeps telling me there is nothing wrong with Sante. We have had it for a year, and I keep track of every tank of gas that I run through it. With mostly in town driving, we get 12-13. That went down to 10 this winter. The dealer suggested that I run injector cleaner in it. When I do, I get bump of 3 mpg for that tank, then the mileage takes a dump back to 10-11. I get that kind of mileage with my 1996 Chevy pickup, I don't expect to get that kind of mileage with my wife's Sante. Since running injector cleaner in the tank increases my mileage by 3, I think it's an injector issue, but the dealer tells me it's not. Air cleaner is good, tire pressure is good ... Any ideas? Am I wrong, or does this sound like an injector issue?
Thanks in advance for your help.
CEL on? Has it been scanned for codes even if no CEL on?
 

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Couple of things. First, start/stop on a ~4000lb vehicle is a mileage killer. Driving habits and poorly timed lights can be a real buzz kill for mileage.

Next, which engine are you running? As Carmine suggests, have you or the dealer checked for codes, and further, has the dealer done any more advanced diagnostic work to see how the fuel trim is working on your vehicle?

Last, what kind of blend are they peddling in Bismarck? Do you switch from a summer to winter blend? Any ethanol added will provide only about 70% of the energy of a comparable amount of ordinary gasoline. Have you been using fuel from different stations, or sticking to the same one?

Injector cleaner is interesting stuff. While the solvents may well assist in improving the spray pattern of a gunked up injector, the injector should not gunk up again immediately after stopping the use of the cleaner. It normally takes quite a great many miles for that to occur unless what's in your tank is complete crap - and I think that in that case, your problems would much more severe - driveability, not just mileage. So what you may be seeing is the effect of the increased energy density of the cleaner (sort of the reverse of the ethanol situation) if you're using enough of it to make a difference.

That doesn't answer the basic 'why' question, but it does correspond with your dealer's impression that it isn't an injector problem. Besides providing some cleaning action, the cleaner burns somewhat differently than normal gasoline.
 

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I'm also in Bismarck and am pretty sure they use winter blend, and cant find anyplace that sells pure gas anymore so the milage has taken a hit.
The op did say it was his wifes santa fe and that could be the reason for poor milage...
My wife gets about 5 mpg less then I do driving the same vehicle.
 

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Discussion Starter #7
I had to laugh. Yes, my wife does drive the Sante, but when I drive it we get the same mileage. The CEL pops on once in a while. It was tested and it is for the fuel gauge sensor, which is going out as well. I understand that hard starts and stops can affect gas mileage. My wife only works a mile and a half from home, with two stoplights. No hard driving at all. I have had the car on the computer and it shows that everything other than the fuel gauge sensor is working fine. The dealer is questioning my fuel readings, even thought I told them that I log miles and gallons for every tank that goes in it. They would like me to fill up the car, and let them drive it around for 4 hours to check mileage. I not only track the mileage, but if it was in town, highway or combination driving. I'd rather not have to pay them $100 and pay for more gas at 10 mpg to find out what I can show them right now. Last time I talked to the service guy, he said without a CEL on, it's almost impossible to know what's wrong.

Which leads me to where I am. Should I not be getting better gas mileage? What's the best way to approach the dealer about it? Like I said in my first post. I get 10 mpg with my 1996 Chevy pushed by a 350. I should be getting a lot better mileage with a 3.5l V6 Sante Fe. Ideas?
 

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Even without hard driving, only driving 1.5 mile each way is probably the main reason for the poor gas mileage. The engine doesn't have time to fully warm up in such a short distance. SO basically, your engine is "always" running in warmup mode (not unlike running with the choke pulled at all times). Not good for consumption.

But since this lower mileage is more recent, I have one question for you: Have you had your rear brakes serviced? Not sure how much de-icing salt, if any, is used where you live but our beloved SF need regular servicing on them or they seize and can cause drag that will reduce your mileage. Many threads on this site with all the info needed. There's even a TSB about it.
 

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Here, try this, get the engine fully warmed up to "closed loop" (learning ) mode, then remove the battery cables touch them together, then step on the brake to make sure everything is discharged, then replace cables, and let it idle for a few minutes, then just drive it in the style you normally do, this should do it!
 

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First, you have a 3.3L engine, not 3.5. It's the same one we have in our 2008 (same trim too, AWD Limited). But yeah something's definitely wrong. Even with my wife driving ours most of the time we get around 18 or 19 at least. Highway trips are usually around 24.

As stated you might want to reset the ECU and then drive it gently for awhile and see if the computer will lean out the fuel mix a little. You also might want to dump a can of SeaFoam in the gas and run that through. It will clean injectors, fuel lines, remove any water in the system etc.
 

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My wife only works a mile and a half from home, with two stoplights.
As noted by several already, it's no wonder her mileage is poor. The cold enrichment cycle probably isn't even completed by the time she gets to work. No vehicle is going to give you decent mileage on trips like that. Further, if this is a regular habit, mind the oil change intervals. That's not even enough time to fully warm the engine for that purpose, either.
 

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He said that he also gets the same poor milage when he drives it, and also gets similar milage with his '96 chevy pickup.
I think with the same person driving both vehicles and driving similar routes the santa fe should get at least a few mpg better then the pickup.
As mentioned before having rear brakes that are seized and not fully released might be the cause for poor milage.
They use alot of road salt here.
 

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Discussion Starter #13
I truly have my doubts that it's the engine not running at warm up temperature. How long should it run to warm up to operating temp? It does live in a comfy heated garage that keeps it at 50 degrees. When we take it on a 200 mile trip, I get 16-18 on the highway. I have a Pontiac Montana with a 3.4 liter that I have loaded with heavy tile when for work, and I still get 22 mpg on the highway. Her previous car was a Ford Taurus with a 3.0 liter and she was getting 18 on the same trips to work. Mid 20s on the highway. I will try the battery trick and then the rear brakes. Thanks for all of the suggestions. I'll keep ya posted.
 

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I am doing no better than 12-13 mpg for the first 1.5 miles of my commute every morning. That will kill you right there.

If you really are getting better fuel economy from running fuel injector cleaner you can pickup a gallon of TCW3 2 cycle engine oil from walmart and add 1 ounce of oil for every 3-4 gallons of fuel at every fill up. Cheaper than fuel injector cleaner and has a great detergent package for keeping things clean.
 

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With repeated mile and a half drives, your wife could be in sunny Florida (assuming there was any sun in some parts of it in recent days) and the mileage would still be poor. 50 (in your garage) to 180 to even begin to open the thermostat would take all of that.

None of which is to try to explain away all of your mileage complaints - only to note that whatever is going on, that kind of driving will most assuredly exacerbate it.
 

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Based on the driving conditions - one could say that the vehicle is demonstrating excellent fuel consumption.
The life of an engine driven with internals soaked in liquid gas is something to be be curios of.
Please, keep us posted in the future with any mechanical issues the engine develops.
 
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