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Hyundai Elantra Maintenance and Repair



  • doohickiedoohickie Posts: 949
    It could simply be that your trip computer is inaccurate. Have you tried calculating the mileage the old-fashioned way?

    1. Fill up your tank to pump shutoff (do NOT top off).
    2. Reset your trip odometer (and/or record the mileage on the main odo).
    3. Drive the way you normally do until your next fillup.
    4. When you fill up, fill the tank to pump shutoff again. Record the number gallons. Divide the number of miles on your trip odometer (and/or the current mileage on the main odo minus the mileage recorded in Step 1) by the number of gallons pumped.

    The result is your miles per gallon. Some people swear by their trip computers and they are very accurate; for others, not so much. If you have a computer that calculates too low of a mileage, the problem is in the computer (measuring either fuel used or mileage incorrectly). I generally trust the odometer and the gas pump numbers more than the trip computer because both of them are used for commerce, while the trip computer is essentially a "toy" and does not necessarily need to be accurate.

    (I have a GLS so I always have to measure it this way; no trip computer.)
  • backybacky Twin CitiesPosts: 18,618
    I'd add be sure to fill up at the SAME STATION and even the same pump both times, if possible. I've found differences of 2+ gallons at different stations as to when the pumps shut off by themselves. I think that may be one of the reasons why some people report that their trip computers are so inaccurate. I've found mine is off by less than 1 mpg if I compare it to manual calculations that I've done based on careful fills at the same pump.
  • doohickiedoohickie Posts: 949
    Or as an alternative, average it over about 5 tankfuls. Any variations in fill levels will average out to insignificance.
  • backybacky Twin CitiesPosts: 18,618
    That might work OK if you are trying to get an overall average fuel economy for the car over a range of different driving conditions, or for a long-distance trip. For me, five tankfuls would be nearly 3 months of driving. If someone wants to see what their fuel economy is for highway cruising, for example, that process won't work unless they do the same kind of highway cruising for 1500-2000 miles.
  • What type do you use on Elantra? For those who used both, did you notice any difference in gas mileage?

    By the way, what kind do dealers use?
  • nj2pa2ncnj2pa2nc Posts: 813
    it is hard to do that in new jersey- it is against the law to pump your own gas. We have found the computer mpgs and our manual calculations are extremely close- when we go to self-service stations we fill it to the brim- not over and never had any problems with any of our cars (knock on wood)when we travel to nj from nc we fill the tank before we leave, drive to Fredricksburg, Va and fill up at the WaWa then make it to Toms River, NJ where a gas attendant fills it up again at the WaWa there.They usually fill it to the nearest dollar(total 635 miles)
  • bjc2bjc2 Posts: 28
    anybody know where i can find a electrical shcematic for
    my 2001 elantra.
  • doohickiedoohickie Posts: 949
    it is hard to do that in new jersey- it is against the law to pump your own gas.

    You mean you just pay the guy and have no idea how much gas they put in???? How do you know you're not getting ripped off? (I mean, even if you don't see the number of gallons, you know how much you're paying per gallon, right? It's easy to figure out the number of gallons from the price paid and price per gallon.)
  • doohickiedoohickie Posts: 949
    anybody know where i can find a electrical shcematic for
    my 2001 elantra.

    Yes, at Hyundai WebTech. Directions for how to get a (free) logon id and how to navigate can be found here.
  • nj2pa2ncnj2pa2nc Posts: 813
    what I meant was you can not always go to the same pump. The first thing the attendant asks is cash or credit.If the gas pumps stops at say $23.81 and you pay with your credit card then the attendant usually leaves it there but if you pay with cash they bring it up to $24.00. It is very easy to figure the mpg. In fact I keep track of the gas I use, where I bought it, the price per gal how many gal and mpg. Oh yes the date. There is a difference in the mpg when I get it filled in NJ and then fill it myself than when I fill it and then fill it again later.
  • doohickiedoohickie Posts: 949
    You should instruct an attendant to NEVER top off. It can cause harm to your evap system, and I wouldn't be surprised if it is illegal.

    Even with that, though, it should average out after a few tankfuls.
  • nj2pa2ncnj2pa2nc Posts: 813
    if it is illegal than I must have broken the law numerous times. I do it all the time-no problems and I plan to continue. I also notice alot of other drivers that do it.I am not looking to argue with you just giving my personal opinion. Love your contributions to the elantra forums
  • re 2688 Harm to evap system. I have heard this comment frequently, but do not understand what is meant. Would you please try to explain it. I usually fill to the next full dollar amount, regardless. What kinds of damages does this cause? When? So far I have never noticed anything out of the norm. Thanks, van :confuse:
  • doohickiedoohickie Posts: 949
    If you overfill a gas tank, it can force gasoline into the vent lines and potentially into the charcoal cannister. If this happens, the system will not vent properly (which is a potentially hazardous situation due to build up of pressure in the fuel tank or at the very least CELs for the Evap or Fuel System) and the affected evap system components needs to be replaced. The evap system includes tubing that runs the length of the car, between the evap cannister in the left rear, the gas tank, and the engine.

    I used to work for a company that made fuel systems for OEM and evap system problems accounted for a LOT of our repair parts (almost as much as fuel pumps).

    I've seen what can happen and I would never top off. But do whatever you want.

    Oh, and with respect to "illegal", anything that messes with emissions is generally illegal to some extent. If you mess up your evap system it can result in added emissions (since the evap system is no longer vented properly) or in extreme cases of topping off you get overflow of gasoline which is also an increase in emissions.

    When I worked in the fuel tank business, the plastic tanks made by the company I worked for had ever increasing permeability standards that practically counted emissions of single hydrocarbon molecules through the tank walls, necessitating different plastics technology to prevent the emissions due to molecules seeping through the tank walls. It sounds minor, but multiply it by the millions of cars on the road, and even a slight improvement in emissions makes a big impact, which is why messing with anything that affects emissions is against the law.
  • ray_h1ray_h1 Posts: 1,134
    )) "I heard so too. and its inside does look the same as Purolator Premium Plus, although parts number is the same as Fram. So I wasn't sure. Is there a link to this?" ((

    Try BITOG and snoop out the oil filter section - there's a handy list there of filter manufacturers. As for Fram part numbers, Fram is so ubiquitous in the marketplace that many independent and store brand filters carry the Fram numbering convention for convenience. I have 30-odd "Castrol" oil filters for my '03 Hyundai Sonata that I bought on closeout for twenty-five cents per when K-Mart was in deep doo-doo. Though they carry a Fram number, they're actually made in Gastonia, North Carolina by Wix. (There's only one oil filter plant in Gastonia...)
  • ray_h1ray_h1 Posts: 1,134
    Good point. I knew it was one of the German filter companies. One thing I'm still unclear on, though, is whether Hyundai's filters (oil and air) are actually provided by Mann in Germany or whether they're manufactured in Korea under license. In any event, Hyundai/KIA oil filters are built like the proverbial brick chicken house.
  • 1racefan1racefan Posts: 932
    Not to mention, the owners manual even mentions that it is not good to top off. I would assume if they put it in the manual, a lot of people that know much more than I must have studied this, and found topping off can pose a problem.

    Like Doohickie says...keep topping off if you want. One of the purposes of these forums is for us to try to help each other when we can, and I think that is all we are trying to do. To be honest, I had never heard that topping off posed any kind of a problem until we bought our Elantra in November of '01, and saw that in the owners manual.
  • ray_h1ray_h1 Posts: 1,134
    )) "By the way, what [oil viscosity] ... do dealers use?" ((

    Heaven only knows. Some dealers charge for 5W-20 and then squirt 10W-30 from their pressure dispenser hooked to a bulk oil drum into anything that drives in. (Though I personally still use 10W-30, ask me why I refuse to entrust oil changes to my dealer or a "gypie boob" shop...) Regarding 5W-20 vs. 5W-30, both behave when cold as a cold 5 weight oil would. When hot, though, 5W-20 behaves as a hot 20 weight oil would. Predictably, hot 5W-30 behaves as a hot 30 weight oil would - a bit more viscous than the former. Some believe the extra viscosity in 5W-30 oil also lends a bit more wear protection. I used to believe likewise, but now I'm not so sure. I now suspect 5W-20 motor oils carry additional extreme pressure additive to compensate for their reduced hot viscosity. One inspection picture on BITOG of a disassembled Ford V8 out of a state trooper's totaled 2001 Crown Vic patrol car at 237,000 miles revealed a still visible cross-hatch pattern in the cylinders from the final cylinder honing tool operation at the time the engine block was machined. This was a car run exclusively on 5W-20 Motorcraft synthetic blend motor oil and had extended periods of idling with commensurate fuel dilution. The main and connecting rod bearings were still within factory specs for new bearings. The piston ring lands were not carboned up and piston skirts showed more of a polished appearance than what could be considered scuffing. There was no sludge, and only a minimal "gold" discoloration from varnish. I don't recall whether the oil change intervals practiced at the department maintenance yard garage were noted, but 5W-20 seemed to be holding up to arguably severe service.
  • Thanks for the info. I have mostly used 5W30 in my 03 Acura even though Acura calls for 5W20. But now I plan to put Quaker State fully Synthetic 5W20 in the Elantra for its first oil change (I got the oil for free after rebate).
  • Re 2691, doohickie
    2694, 1racefan
    Thanks to both of you for the info. I never noticed it in my manual, yes, I think it is there, I just must have missed it. I guess I am just a creature of habit. I will try my best to change to stopping with the "shut-off" from here on out. Do you think I will be OK at this point? 6000mi on my Hyundai. Would the same thing apply to my 2002 Merc Sable with 27000mi on it?? I appreciate the sharing of information for the betterment of us all. Let's face it another little bit of gas in the tank at the time isn't that important. Again, thanks..van :)
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