Hello, it's my first time here as a new Hyundai owner. Few weeks ago I purchased a brand new Sonata 2.0 equipped with a CNG kit installed by Hyundai itself.
I expected a fuel mileage (burning regular gasoline) of about 28-30 MPG since I usually drive on flat land and out of town but I can't get better than 19 driving carefully.
I'll have the car checked but today I literally stopped a guy with the same car on the road and had a look at his trip computer, he was performing worse than me...?!
Do you guys think that the 2.0 engine is under performing for this car? It has 144 Kw/6000 compared to 161 of the 2.4 while torque is 185 to 219 N.m./4500. Running on natural gas I don't spend that much but still I'm disappointed of such a bad fuel economy.

It's really hard to have an opinion, since your using CNG.

You mention CNG and RUG. Which are your fuel mileage numbers based on?

Assuming RUG, many of the members here are based in the USA and only have experience with our spec engines. Maybe another 2.0 owner will be able to chime in on your motor. My 3.3 V6 usually returns 23 mpg with an average speed of less than 30 mph, meaning most of my driving is urban. When I get on the highway I average 29-30 mpg, up to max 33 mpg (all in US gallons, not Imperial), doing 70 mph at elevation (roughly 4,500 feet). I'd be awfully disappointed with 19 mpg on a 4 cylinder cruising on flat roads. If the vehicle is brand new then you are still in break-in, but still, I wouldn't expect a major leap in mileage following break-in. Have you checked tire inflation? Brake pad dragging?

-Ty

This post has been edited by thetyguy: Sep 21 2009, 12:17 PM

I've a 2.0 Petrol Sonata NF for about 20 months now, the average fuel consumption has been around 22-24 mpg (~ 9.5 - 10.5 l / 100km) ever since I got my car early last year. My average speed per the trip computer is just ~ 30 km/j.

Thanks guys,

my numbers are referring to RUG, I'm now running only on RUG to test the fuel economy because I saw an awful pattern while running on CNG and efficiency will affects CNG mileage as well.
I checked tire inflation and then mentioned the problem to the Hyundai dealer, the engineer said to wait until the engine has at least 3 - 4 thousands kms as I'm still breaking-in, but I hardly see how MPG can improve that much.
What worries me is the other guy driving exactly the same car had even a worse performance, that made me think that mine hasn't a particular problem (still I'll have it inspected for brake pads and any other possible causes).
I thought that the 2.0 engine isn't powerful enough, or maybe Hyundai engineers have changed injections specs installing the CNG kit... but it sounds strange, I got other 2 cars where I installed an CNG kit and RUG MPG just remained the same.

Geekfiredog

my engine is a DOHC, is it the same as yours? Do you know if Hyundais in Malaysia are imported, assembled or manufactured?

My trip computer says 12.2l/100km from the second day and I don't think it will improve after break-in.

Thanks

Hi Robbi00,

my engine is also a I4 DOHC and I believe we have the same engine (with ~ 144 hp) - the original NF, not the facelift version with higher power (163 hp?). Earlier batch of Sonata NF (both 2.0 and 2.4) were fully imported into Malaysia, later batch were assembled in Malaysia, mine was assembled in Malaysia.

My trip computer was at ~ 10.6l/100km after the first 1000km, and gradually improved to ~ 10.2l/100km after @ 25,000km, the it was accidently reset (I myself don't know how it happen since I didn't reset it) and it is hovering around 9.9 - 10.0 l / 100km recently (@ 30,000km now). My manual calculation shows ~ 10.3l/100km since I got the car, and ~ 10.25l/100km for the last ~5000km

Welcome. (IMG:style_emoticons/default/00000732.gif) I am going to send this thread over to our Asia Pacific section for other members in your Area to read!

You can always post at the home of the 4G Sonata too. Not that much going on over here it seems. (IMG:style_emoticons/default/innocent.gif)