Hyundai Forums banner

1 - 20 of 39 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
Hi Guys

I have just joined this forum. My question is about my Hyundai Sonata 2007 GLS 2.4. My gas mileage is 6 km per litre or 14.11 MPG which I think is pretty low as mentioned on the fueleconomy.gov 2007_Hyundai_Sonata.shtml

"2007 Hyundai Sonata 4 cyl, 2.4 L, Automatic 4-spd - Combined 24MPG"

I have googled and done some work and changed so many things in my car but mileage is still the same. I don't know if everyone has this problem. What I have done so far:

1. Checked my tires PSI > 30-31
2. Trunkload should be low
3. Changed Engine Oil, Air Filter and Oil Filter

After that checked my mileage for a couple of months but still the same.

4. I went to a mechanic did the inspection with a computer(OBD II or something) after attaching to my car and said that all is good.
5. Then I changed all 4 spark plugs and I put the ones with platinum I remember after discussing with Canadian Tire representative.

I don't know what should I do. Hyundai Service centre said they can check for CAD $149.99, I want to check if I could by this forum's help.
 

·
Registered
Joined
·
882 Posts
Replace MAF sensor, clean throttle, check brake. For tire pressure I will set at 33-35, 33 for winter and 35 for summer, then reset MPG
 

·
Registered
Joined
·
17,552 Posts
Dont know where you at or which market,, no location reflected in your profile to show in box under username..

1 - If it as cold there as it is here,,,, forget mileage

2 - inflate them tires to 35-37

3 - engine came with DENSO IRIDIUM,,, Platinums was a downgrade (100,000 Iridium / 60,000 Platinum)

4 - Check for vacuum leak at intake runner number 1 at cylinder head,, engine idle and can of carb or brake clean spray serve purpose.. you'll know if it has leak when spray hit it and get sucked in

5 - If I recall, this fuel system does not use MAF,, it has MAP.
 
  • Like
Reactions: Old's Cool

·
Registered
Joined
·
244 Posts
This is on my 2006 4cyl. You didn't mention anything about your driving habits. Do you do alot of idling? Are you driving a short commute? I don't drive much anymore so I only fill up maybe once every 3 weeks but I do a MPG calculation. Typical commute plus some idling, I might be down to 18-20MPG. If I have a long highway trip without stops, I might get up to 27 if I'm lucky. In the winter with snow, my mileage goes down even more.

Isn't the spec tire pressure only 30psi?
 

·
Registered
Joined
·
17 Posts
Discussion Starter #5
Camper, what are MAF sensors? Do I have that in my car? Can I do it myself by learning on YTube? Do you think resetting MPG will really help?

sbr711 is saying it is MAP? what should I do? I don't know :-(
 

·
Registered
Joined
·
17 Posts
Discussion Starter #6
Dont know where you at or which market,, no location reflected in your profile to show in box under username..

1 - If it as cold there as it is here,,,, forget mileage

2 - inflate them tires to 35-37

3 - engine came with DENSO IRIDIUM,,, Platinums was a downgrade (100,000 Iridium / 60,000 Platinum)

4 - Check for vacuum leak at intake runner number 1 at cylinder head,, engine idle and can of carb or brake clean spray serve purpose.. you'll know if it has leak when spray hit it and get sucked in

5 - If I recall, this fuel system does not use MAF,, it has MAP.
1. I am new here. Did not filled my profile yet. I am in Montreal, Canada and yes temperature here is really cold, but anyways I am observing my car's mileage since last year.
2. In my car window, it says to keep 30-31PSI. Should I inflate to 35-37?
3. Yes, you are right, it was DENSO IRIDIUM but platinum wasn't a downgrade as a person said in Canadian Tire. He said that Iridium is good as they last long for 1,20,000kms, Double Platinum 80,000Kms and platinum which I bought are good for 40,000Kms. So I don't plan to use this car for 40,000kms for now so I chose that one.
4. I forgot to mention when I bought this car back in Dec16, I replaced transmission oil, transmission oil cap(not sure what they call), brakes and brake pad. Can you please tell me how can I check vacuum leak?
5. MAP or MAF, what should I do?
 

·
Registered
Joined
·
17 Posts
Discussion Starter #7
This is on my 2006 4cyl. You didn't mention anything about your driving habits. Do you do alot of idling? Are you driving a short commute? I don't drive much anymore so I only fill up maybe once every 3 weeks but I do a MPG calculation. Typical commute plus some idling, I might be down to 18-20MPG. If I have a long highway trip without stops, I might get up to 27 if I'm lucky. In the winter with snow, my mileage goes down even more.

Isn't the spec tire pressure only 30psi?
My driving habits are good. When I came to know about bad mileage, I take care of my driving especially. I speed up slowly and no sudden brakes, not too much overspeeding etc. I drive almost every type. My car was idle/normal usage for 2-3months. I did pizza delivery for a month. Now driving Uber for a while. As a student, I switch jobs but my car mileage is same! don't know why.
 

·
Registered
Joined
·
8,160 Posts
I'll second raising the tire pressures but the cold will kill gas mileage. Maybe the thermostat is not keeping the coolant at 180F+? I wonder what the gap is on the spark pugs?

My Accent is down 5 mpg with the cold this year.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #9
I'll second raising the tire pressures but the cold will kill gas mileage. Maybe the thermostat is not keeping the coolant at 180F+? I wonder what the gap is on the spark pugs?

My Accent is down 5 mpg with the cold this year.
So what is the fix for a thermostat? Should I go for a complete checkup of my car at Hyundai Service Centre? it will cost me $149.99 and I am not sure what they will check, maybe they will just connect that computer(ODB or something) and do that only?
 

·
Registered
Joined
·
8,160 Posts
No don't go to the dealer yet. You need to see just how hot the car is getting and how fast it gets up to temp. Cardboard in front of the radiator will help.

Not sure of the specs for your engine as far as temp.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #11
No don't go to the dealer yet. You need to see just how hot the car is getting and how fast it gets up to temp. Cardboard in front of the radiator will help.

Not sure of the specs for your engine as far as temp.
Thanks, Red. My car takes 10-15mins if I keep the car running but if I start driving, it takes around 5 minutes. I have a feeling that my car's heating system is normal. The pointer in of heating stays a little below to the middle always where heating C/F is mentioned while I drive.
 

·
Registered
Joined
·
882 Posts
Camper, what are MAF sensors? Do I have that in my car? Can I do it myself by learning on YTube? Do you think resetting MPG will really help?

sbr711 is saying it is MAP? what should I do? I don't know :-(
MAF sensor is easy to replace, it's between air filter upper cover and throttle pipe. Your car doesn't have MAP
 

·
Registered
Joined
·
17 Posts
Discussion Starter #13
MAF sensor is easy to replace, it's between air filter upper cover and throttle pipe. Your car doesn't have MAP
Camper as I mentioned, A mechanic did the inspection with some tablet after attaching to my car and didn't tell me anything about MAF problem. Maybe he missed to check that.
I have seen a video on YouTube that if MAF is bad it will display error code in the OBD type meter.
 

·
Registered
Joined
·
13,349 Posts
Dont know where you at or which market,, no location reflected in your profile to show in box under username..

1 - If it as cold there as it is here,,,, forget mileage

2 - inflate them tires to 35-37

3 - engine came with DENSO IRIDIUM,,, Platinums was a downgrade (100,000 Iridium / 60,000 Platinum)

4 - Check for vacuum leak at intake runner number 1 at cylinder head,, engine idle and can of carb or brake clean spray serve purpose.. you'll know if it has leak when spray hit it and get sucked in

5 - If I recall, this fuel system does not use MAF,, it has MAP.
Damm, man, you're in FLORIDA!

If it is as cold as it is HERE (New England), just throw the mileage out the window and live with it! I'm getting 29 overall, which is exactly what I have for the past 3 winters (Accent...). Now that I;m driving !48 miles a day, it has gone up 1 MPG.

These cars get horrible fuel economy in the winter. But, you remember that from living in the Northeast, right?! ;)
 

·
Registered
Joined
·
13,349 Posts
1. I am new here. Did not filled my profile yet. I am in Montreal, Canada and yes temperature here is really cold, but anyways I am observing my car's mileage since last year.
2. In my car window, it says to keep 30-31PSI. Should I inflate to 35-37?
3. Yes, you are right, it was DENSO IRIDIUM but platinum wasn't a downgrade as a person said in Canadian Tire. He said that Iridium is good as they last long for 1,20,000kms, Double Platinum 80,000Kms and platinum which I bought are good for 40,000Kms. So I don't plan to use this car for 40,000kms for now so I chose that one.
4. I forgot to mention when I bought this car back in Dec16, I replaced transmission oil, transmission oil cap(not sure what they call), brakes and brake pad. Can you please tell me how can I check vacuum leak?
5. MAP or MAF, what should I do?
Yeah, man, up the inflation in your tires. If you're using real snow tires, a few more PSI won't matter. (kg/whatever you Canadians use...;) )

It;s been bitter here for a few WEEKS, and fuel economy in these cars suffers. A few more pounds of air won't make a great difference in the ride, but you will see a marginal increase in economy.

All bets are off with Hyundais when the weather gets cold, apparently.
 

·
Registered
Joined
·
4,232 Posts
I would have a close look at the O2 sensor with a scan tool. They deteriorate with age. Or just replace it. If it's the original its like me. Too old and needs replacing. Our local Commodore (rest in peace) takes about 2 years after it begins to fail to log a fault code so for little cost replace it.
 

·
Registered
Joined
·
13,349 Posts
@Old's Cool
yeah, you are right. But I have an intuition that there is some problem with the car for sure. I don't know why may be I bought second-hand that's why.

My Accent has been doing better now that we are out of the Deep Freeze! :frozen:
 
1 - 20 of 39 Posts
Top