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Hyundai Sonata Fuel and Fuel System Questions

bill118bill118 Posts: 3
edited September 2014 in Hyundai
My car is 2006 sonata GLS I4, do you guys think it is a good idea to upgrade to premium gas?


  • backybacky Twin CitiesPosts: 18,934
    Only if you like paying about 10 cents more per gallon for gas than you need to. The engine is designed to run on regular unleaded.
  • drdonrsdrdonrs Posts: 164
    why oh why would you even consider the proposition to switch to premium? The engine is controlled by a computer chip and is set for regular gas. Be happy that it is what it is. Even my Azzy also runs on regular. Of course you might want to make Exxon/Mobil and the other oil companies a little richer and your wallet a little thinner by an unnecessary switch.
  • bhmr59bhmr59 Posts: 1,601
    Gee, you're lucky if you can get by wasting only 10 cents per gallon. In my area of CT the difference in price for premium is 20 cents per gallon. ;)
  • jacknzonejacknzone Posts: 82
    Hi Bill118
    You may like to look at (Hyundai Sonata Real world MPG Numbers ) on page 61 #303
    I found it was around about the same , I'm back using 91 octane, 95 is a $1.529 a litre here . :D
  • patpat Posts: 10,421
    Seems to me that provides the definitive answer.
  • joe97joe97 Posts: 2,248
    Regular unleaded.
  • patpat Posts: 10,421
    Then, as noted earlier, it's only a waste of money to burn premium. The engine is not built to take advantage of it as everyone has noted.
  • I have a 2007 Sonata Platinum ediiton. In the manual it says 87 or 89. I've been using 87 but have noticed minor engine knock. I took it to the dealer and they said this was normal, and will decrease over time since the car hasn't been broken in yet(I only have 700 miles on it).

    My wife recently(a few weeks ago) bought a 2007 Elantra SE. She mistakingly filled up with 89 one day. She told me of her error, and I told her next time use 87. When she filled up the next time with 87, she and I noticed the minor engine knock that my car had been experiencing. Not sure if this is how all Hyundia's are supposed to sound since these are our first Hyundia's. But I'm gonna fill up next time with 89 and see if my engine runs better.

    Any suggestions/experiences?
  • You could try 89 octane but that is still a couple cents more than regular. With regard to the "knock" there should be none on either car using regular. There is, on both cars, a knock sensor that constantly fine tunes the timing and retards it if it detects any detonation (knock). It has been a very long time since new cars "knocked" so maybe what you hear (although it is hard to hear it inside) are the fuel injectors activating. They tick or click all the time and are audible at idle.
  • I took a second look at my maunual and it says for the 2007 Sonata that gas of octain 87 or higher can be used. So i filled up with premium yesterday, and i'll let you guys know if I notice any difference.
  • Sure, you can use any grade gas but Hyundai sets the minimum when they state 87 octain. The "or higher" part of that statement is purely optional (Hyundai is NOT saying you can't use it) so, yes, you can spend more for premium but I,like others here,say it is a waste of $$$.
  • bj02176bj02176 Posts: 115
    It may be a waste of money on the bigger engine, but not on th 2.7 awd, try 89 or higher and see if you do not feel more confident merging on rt 128 with it versus 87. No better gas mileage however.

    I thought they were saying in the manual to use 91 or higher for better performance, I could be wrong, but I think that is what it says in mine, and a true statement if that is indeed what it says.
  • targettuningtargettuning Posts: 1,371
    At one time we owned a 2002 Santa Fe with the 2.7 V-6 and AWD. Since I don't own it any longer I can't do the test you suggest but I never used anything other than 87 in it and don't recall any reason I should have upgraded to 89. I personally don't belive the minor increase in octane from 87 to 89 makes any appreciable difference in vehicle performance and ,for sure, none in fuel economy. It is, especially now, a waste of money for the vast majority of new cars owners. In fact, since probably 98% of all new cars are designed for regular (87 octane) and run perfectly well with it I can't understand why three grades are still available. Aside from some high end luxury cars, some luxury SUV's and very high performance cars premium (92 octane) is pretty much unneeded. You may gain optimal performance with those engines designed for premium if you use it but I'll bet not 1 in 100 Corvette owners could tell the difference if they used mid-grade instead and "lost" a few hp because the engine management computer "dialed back" a few design parameters because of it. Those engines are so massively powerful anyhow nobody would notice.
  • bj02176bj02176 Posts: 115
    I think they retuned the engine, however if you want to merge on rt 128 with just using 87 be my guest, around town the sluggish 87 is fine, but for highway merging 89 alternated with the next higher grade performs best. Just get the bigger engine and be done with.

    Or get a CRV 4 cyl which I believe will accelerate just as well as 2.7 hyundai on 87, and better gas mileage to boot.
  • bhmr59bhmr59 Posts: 1,601
    My '05 SONATA with the 2.7 V6 accelerates very nicely at 87 octane; it's designed to run on 87 octane. No need to spend the extra $.10 per gallon for 89 octane. I've never had a problem merging into traffic, even accelerating up to 80 just because some inconsiderate driver wouldn't back off for 2 seconds to let another car in.

    But then maybe your rt 128 is a different rt 128 than somewhere else, wherever rt 128 is.
  • targettuningtargettuning Posts: 1,371
    Thanks for your input but I fail to see the point of the post for the following reasons:
    1. I don't and never have merged on Rt 128 and I don't even know where it is.
    2. I have never stated I am or was unhappy with the performance of the 2.7 V-6 we had owned. Since we no longer own it it is a moot point.
    3. I am not in currently the market for a car "with a bigger engine" OR a Honda CR-V. I wasn't asking for your or anyone elses opinion about which car or engine I should buy.
    This started out to be my opinion about the uselessness of using a higher grade fuel than stated by the manufacturer and somehow now I have an argument about merging on Rt 128?
    If you feel better about your merge using premium by all means..go for it!!
  • While filling up, I recently discovered that my 07 Sonata Limited doesn't have an "inner" door at the top of the gas tank filler neck. On all the other cars I've owned, I'd see a metal "door" that covers the filler neck once the gas cap is removed. I believe that door functions to prevent gas from the tank from splashing out. Can anyone who owns a 06 or 07 Sonata verify whether the inner door exists for me? Thanks in advance!
  • bj02176bj02176 Posts: 115
    I thought this was about premium gas, you did mention a Santa Fe 2.7, I said the same retuned engine in a 2007 with more horse power gets better acceleration with 89 or higher.

    Around town 87 may be okay, not on the highway. 128 is in Boston, it's the same for merging on any highway in a major city which Boston is.

    The manual for my 2007 says for better performance use 91 or higher, I find it to be true.

    Whether or not you own the car you are still saying other than 87 is a waste, on most cars it probably is, not on this particular Hyundai in my opinion.
  • No "inner door" here, either. I'm not certain, but I think those were put in as an anti-theft/siphoning measure. Gas theft used to be a big problem. Probably too much work for thieves now, they steal directly from the gas pump by driving off without paying. Or use stolen credit cards. Anyway, no need to worry. Enjoy your ride.
  • bhmr59bhmr59 Posts: 1,601
    The topic here is "Hyundai SONATA premium gas."
  • Thanks, wanna_azzy, for checking things out for me! I doubt the purpose of the "inner door" is for theft prevention, though. I think thieves can still siphone the gas given that the door is there, much the same way that the door can be pushed in (to open) when you insert a tube, e.g., the gas pump nozzle. I remembered reading somewhere--from my Intrepid manual (?)--that the door is referred to as a splash guard of some sort, but I could be wrong. Anyhow, it's good to know that I'm not missing anything. Thanks again!
  • targettuningtargettuning Posts: 1,371
    I think that inner door or flap a couple of inches or so down inside filler neck was originally a functional feature that prevented leaded fuel filler nozzles (which were larger) from being inserted in "unleaded only" vehicles. Since unleaded fuel nozzles are slim only they could be used. Now long after leaded fuel has disappeared this feature has also, it seems, disappeared. That said I haven't bothered to look on our 2006 Civic to see if still has one but if it does I don't know the current function. Couldn't be splash back prevention, at least while filling because the door is open at that
  • That flap is only a splash guard to prevent gas from sloshing out while the car is in motion. An anti-siphon feature would be a mesh screen in the filler neck that lets gas in as you fill up but blocks a hose inserted down the opening.
  • targettuningtargettuning Posts: 1,371
    The splash guard idea would only be necessary if someone filled the tank to over-capacity (and only even then until you burned off a gallon or so) plus the screw on cap seals the tank and makes it a closed system for emission reasons. Over capacity is, not only filling the tank but also filling the filler tube to the top. Since this is a no-no with modern cars one shouldn't be doing it anyhow. So I am still at a loss to explain that flap...if it is still there on the newest cars and apparantly the 2007 Sonata (at least) doesn't have it. Maybe it is finally being phased out?
  • bj02176bj02176 Posts: 115
    Which could be my next vehicle if I swith to a sedan, if it doesn't run well on 87, then I will go with Honda or Toyota.

    I was responding to someone with a Sante Fe that posted on this forum with 2.7 engine.

    If you don't like my posts, don't read them.
  • patpat Posts: 10,421
    But the point that this is not a discussion about the Santa Fe is a valid one, so it would be best to just let that go here, no matter the engine. There should be a Santa Fe Real World MPG discussion where these things could be pursued.
  • my 04 sonata has a metal flap at the top of the neck ,of the tank .I thought it was to stop gas vapour or fumes escaping before and after filling your car up, why I say this , is because the Flap is on a spring .
    91 oct V 95 oct or 87 V 89 Oct
    I think for myself it's a waste of money to use higher octane than you need too !
    I posted this in March (Hyundai Sonata Real World MPG)page 16 #303
    I have put it to the test , Four weeks on 91 oct and four weeks on 95 oct ,got a average 22 mpg 91 oct and the same for the 95 oct , city driving / Trip computer average speed 32 kph / AC on. There was no noticeable different in performance .65 litres per tank 5 cents different in price between91/95 Using 91 for me over a year is a saving $85.00
    And I still using 91oct I think the best way to save money on the gas,is in the way we use our right foot.

    The Test is to try it out for yourself ,using the different Octane and the way you use your right foot. :D

    Cheers Jack
  • ms090870ms090870 Posts: 9
    I have a 2001 Sonata. The car have been incredible as far as dependability and economics. This car has 97000 miles on it and in the entire time that I have owned the car, the only work that I have had to do to this car is to replace a rear wheel hub. So needless to say I extremely happy with my car and will purchase an other car from Hyundai the next time I purchase a new car.

    I am currently having a problem with the filling up of the tank. The pump pops like the tank is full but it of course is not.

    I would appreciate any help you can give me.

    Thank you
  • canddmeyercanddmeyer Posts: 410
    Try another pump. This happens to me on a different make of vehicle once in awhile, but I attribute it to something going on at where I'm getting the gas as it's not consistent. I always noticed the pumps have higher pressure when there are less people fueling up and when the stations tanks are full.
  • patpat Posts: 10,421
    Some personally directed posts have been removed. Let's all play nice. It's too early for the heat to be getting to everyone and too late for cabin fever, is it not?

    Althought it's too hot for my tastes where I am today, no doubt!!
This discussion has been closed.