Fuel Consumption High

[fundew]

my hyundai accent 2004 consumes fuel but does not bring out black smoke, what can i do?

[01Accent16]

My fuel usage is high as well in my 2001 Accent GS. The cold weather causing higher cruising RPMs doesn't help either. I have installed Bosch Platinum +2 plugs and a K&N filter and noticed a slight difference. But from work and back (45 miles) at 65mph 5 days a week and without driving my car on weekends, I try to get 7 days out of a full tank. It sucks.

[DemonDomen]

I drive a 2004 Accent 1.6 manual and get about 6.7 l/100km at 120 km/h (35 mpg at 74 mph).

[Albinus]

Originally Posted by fundew

my hyundai accent 2004 consumes fuel but does not bring out black smoke, what can i do?

Start with the basics... when did you last replace your spark plugs and air filter (a plugged air filter is often the source of poor fuel economy)? How old are the ignition leads? Where are you, what kind of fuel are you using and how hot/cold is it? (as 01Accent16 correctly said if it's cold that can affect mileage)

Originally Posted by 01Accent16

I have installed Bosch Platinum +2 plugs and a K&N filter and noticed a slight difference.

I'd be interested to see how you go long term with those plugs - in my experience with the Alpha engine either NGK or Denso plugs work best - Champion are terrible and Bosch mediocre.

Originally Posted by DemonDomen

I drive a 2004 Accent 1.6 manual and get about 6.7 l/100km at 120 km/h (35 mpg at 74 mph)

I was getting the same in my LC until I replaced the upstream O2 sensor - then it dropped to 5.5L/100KM at 110KM/h

[austex04]

Please also note winter blend fuel does not contain as much energy as summer blend. Do you have a check engine light on? When was the last time the spark plugs, air filter replaced? Do you have a lazy o2 sensor? A scan gage with live data will tell you the voltage output of the o2 sensors, so you will know which one is bad if so. Vacuum leaks, such as bad pcv valve or hose, or intake leaks will cause a lean burn condition that the pcm will create a rich fuel mixture to correct. Bosch spark plugs, esp the ones with 2 or 4 electrodes do not work well in asian and american cars, becouse it takes a very high energy ignition set up to produce a strong enough spark with those, many higher end european cars have this, not ours. Ngk, autolite, and a couple others work correctly with our cars.

[01Accent16]

[QUOTE=Albinus;1178788]Start with the basics... when did you last replace your spark plugs and air filter (a plugged air filter is often the source of poor fuel economy)? How old are the ignition leads? Where are you, what kind of fuel are you using and how hot/cold is it? (as 01Accent16 correctly said if it's cold that can affect mileage)



I'd be interested to see how you go long term with those plugs - in my experience with the Alpha engine either NGK or Denso plugs work best - Champion are terrible and Bosch mediocre.

Well I tried the Bosch plugs cause my father has installed them in a GTP and his HEMI, and has noticed increased fuel mileage. I check them every oil change and they still come out looking perfect. No burning or anything. I've had them on for about 60k miles.

[Albinus]

Originally Posted by austex04

Do you have a lazy o2 sensor? A scan gage with live data will tell you the voltage output of the o2 sensors, so you will know which one is bad if so.

Another trick if you don't have access to a scan tool is to physically unplug one and drive a significant distance. If fuel economy is unchanged, it's a good bet that the O2 sensor is bad. If fuel economy drops, it was doing its job and not at fault.

Bosch spark plugs, esp the ones with 2 or 4 electrodes do not work well in asian and american cars, becouse it takes a very high energy ignition set up to produce a strong enough spark with those, many higher end european cars have this, not ours. Ngk, autolite, and a couple others work correctly with our cars.

Originally Posted by 01Accent16

Well I tried the Bosch plugs cause my father has installed them in a GTP and his HEMI, and has noticed increased fuel mileage. I check them every oil change and they still come out looking perfect. No burning or anything. I've had them on for about 60k miles

I've noticed that most European cars do better with Bosch plugs, but you're a lucky man if you're having such good luck with them on an Alpha engine. An auto electrician explained his theory to me once - the Bosch plug has a finer, weaker but more accurate spark, while the NGK has a less accurate, but stronger spark - that Korean engines generally seem to favour.

[01Accent16]

So exactly what plugs do the Alpha favor? I figure I'll give them a try when she is due for new plugs. The NGK Iridium ones?

[Albinus]

Originally Posted by 01Accent16

So exactly what plugs do the Alpha favor? I figure I'll give them a try when she is due for new plugs. The NGK Iridium ones?

If you don't mind changing them more frequently, save your money and use the bog standard BKR5ES-11 ones fitted at the factory. I used colder plugs (BKR6ES-11) when driving extended periods during hot weather, but if you use those in cooler weather for short trips don't be surprised if they foul up (as they won't get hot enough to burn the contaminants off)

That said, I was only replacing the basic NGK plugs every 30,000KM... for A$16 can't go wrong

[paxil]

is it necessary to reset ecu after changing air filter?