ecotec fuel economy

[brodiewilson]

Hi i am getting around 11.2l/100km doing 90% highway driving is this bad? what kind of figures are other people getting my mate has a vy auto and gets around 10l/100km doing 50/50 town and highway alot of people seem to think manuals get better fuel economy but i dont see how that would be possible as mine sits on about 2500rpm at 100km/h and every auto commodore i have driven sits under 2000rpm.

[VYMAD]

Yeah mate, that's a bit high IMO. Mine is currently sitting on 9.8l per 100k's, and that's around 50/50 large town and 80 kp/h country roads. I'm also just about due to replace my o2 sensors which may bring that down slightly.

[shaune_m]

Yep sounds abit high. Mine has varied between 8.9 - 9.6 over the last 20,000kms. Thats doing about 1000kms a week. 60% highway/40% city.

[dah_man_ben]

Definitely high. Driving on highways, mine sits at about 8.5l per 100km.... in the CBD, sits at about 12l per 100km and in the hills, about 10L per 100km. AND 2500rpm is insane... mine sits at like 1800rpm at 100km/h. By the way, my commodore is AUTO. I don't know what RPM you car should be sitting at considering that it is manual, but I do think 11.2 is high.

Ben

[greenacc]

2500 in 5th is very high, check your diff ratio, maybe someone has changed your diff gears, that would explain the high fuel and high revs ?

[Full Spectrum]

She's up. I would be in the 9's to 10's with that amount of highway driving. i'm in a VT S2.

Your 100 rpm does seem high. Usually it's under 2000rpm @ 100. It might not be getting into overdrive, or is it converter lock up they call it ?.

[one_and_only2004]

It's a manual. They sit at about 2400rpm @ 100km/h.

[Sean880]

With 90% highway driving you should be below 10 litres per 100 km even with a manual. Bear in mind that the manual and auto V6s use the same diff ratio but the manual has a significantly lower gear box ratio in it's top gear.

Top gear ratio 5 sp manual - 0.81 auto - 0.70. Thus you will be running a faster engine rpm in top gear with a V6 manual and using a bit more gas. (These are the ratios for the sedans and wagons and as far as I know the V6 utes are the same).

If you have a clogged up engine air cleaner element your fuel consumption will suffer. If it has not been changed for a year change it. They are very inexpensive and are dead easy to change yourself. Just give the air box a good wipe out and vacuum out before you fit the new element in place. While you are at it also add a bottle of injector cleaner into your petrol tank ever 6-9 months or so.

At the end of the day how you drive is a major factor in fuel economy.

Finally if you are carrying a load in your ute most of the time your fuel use will rise. More weight usually = more fuel to move it.

[wortus]

My car's an automatic and day to day driving in Sydney which is never in heavy peak hour, the odd trip on the M4 and M5 I am getting about 10.5L/100km using E10 fuel. Prior to that I was just below 10L/100km on 91 octane. I generally don't drive in really heavy peak hour traffic. Country trips I have got as low as 7.5L/100km.
Car's done about 142,000km and as far as I know the O2 sensors are still the original ones.

[brodiewilson]

thanks for the replys i pulled the air filter out and there wasn't much dust in it. Its a k & n panel filter so i will get a recharge kit and give it a proper wash. How likely is it that my o2 sensors are stuffed and how can i test them? Also i will get a bottle of injecter cleaner, any particular brand to look out for?

[hsv91ss]

I get no where near the figures above, I am lucky to get 300km local on 95 and V power and approx 420 Freeway and it also is a Auto Ecotec just with an exhaust and a pod I really need to get rid of the pod I hate it could a pod cause extra consumption?

[Full Spectrum]

She's up. I would be in the 9's to 10's with that amount of highway driving. i'm in a VT S2.

Your 100 rpm does seem high. Usually it's under 2000rpm @ 100. It might not be getting into overdrive, or is it converter lock up they call it

Nob it's a manual.

[VYMAD]

thanks for the replys i pulled the air filter out and there wasn't much dust in it. Its a k & n panel filter so i will get a recharge kit and give it a proper wash. How likely is it that my o2 sensors are stuffed and how can i test them? Also i will get a bottle of injecter cleaner, any particular brand to look out for?

I read on this site that o2 sensors have a life of around 120,000k's. I use Nulon petrol injector cleaner, one bottle treats three tanks, though I make one bottle do four or five, not keen on using it too strong, just in case it stuffs something up, even though it states that over treatment won't pose a problem.

[delcowizzid]

after about 70000km o2 sensors start to wander away from where they should read

[VYMAD]

after about 70000km o2 sensors start to wander away from where they should read

Fair dinkum? Well that's a fair bit less than I had previously read. Might have to hurry up and get some newies if this is true.

[Full Spectrum]

What about some engine carbon clean ?.

[wortus]

Fair dinkum? Well that's a fair bit less than I had previously read. Might have to hurry up and get some newies if this is true.

I'd just be monitoring the fuel consumption and spark plug colour and think about new O2 sensors when it was evident the car was running a bit rich.
I don't know if it's really nessecary to replace them until they start to muck up.
Excessive fuel consumption can be caused by other factors as well, for example if the EGR valve is faulty it can effect the fuel octane requirement of the engine, so if the EGR is not working properly the ECU may retard the spark timing and increase fuel consumption.

[markbaja]

Where are the 2 o2 sensors located, and how much do they cost and are they easy to change??

Sorry about the questions, but mines on 113k Ecotec VY, so if they last 120k, should do them soon.

Also, leads? How often should they be changed? Mine a still factory.

As for fuel, I haven't reset mine for over 3k ish and it's on 9.6lt per 100k.
Stock Exec Auto.

[greenacc]

113K is a long run for your leads though they are probably good for that time. I had the original oxygen sensors in a VS ecotec for 250K so don't panic about those based on k's alone, but plugs, leads and oil and air filters are all important.
How is your VY economy compared to your VZ ? thats probably the best guide in your case. If your not getting over 400k's to a tank in a VY on regular 91 you have a problem.

[wortus]

113K is a long run for your leads though they are probably good for that time. I had the original oxygen sensors in a VS ecotec for 250K so don't panic about those based on k's alone, but plugs, leads and oil and air filters are all important.
How is your VY economy compared to your VZ ? thats probably the best guide in your case. If your not getting over 400k's to a tank in a VY on regular 91 you have a problem.

Spark plugs and air filters are by the service book changed every 45,000km max or sooner if the driving conditions dictate, this info is in the owners manual and service booklet. The spark plug leads you need to check their resistance when you do the plugs, if the resistance is too high replace the leads otherwise they are OK. You can do the set or just the faulty one. On my VN one lead went open circuit, I just used a 2nd hand lead off a VT to replace that one only and all was fine for years afterwards, that said if one went on the VY I'd probably replace the whole set.
I'd be worried if my VY did less than about 650km a tank when driven to and from work etc. If the motor is working properly and everything on it ie EGR the fuel consumption should be virtually the same on 91or 95.

[jr689]

Hey I'm new so go easy on me haha, but yea my manual vy s pack commodore does about 2000rpm at 110km/h so yours definitely seems a little high, however being a ute and all, I'd put my money on the fact that your diff ratio's are completely different to mine but it's definitely worth a look in!

[wortus]

Hey I'm new so go easy on me haha, but yea my manual vy s pack commodore does about 2000rpm at 110km/h so yours definitely seems a little high, however being a ute and all, I'd put my money on the fact that your diff ratio's are completely different to mine but it's definitely worth a look in!

The wheel size would also have an effect. For example a VY executive normally has 15" wheels with 205, 60 series tyres however my VY 25th Anniversary has 16" wheels with 60 series tyres which are a lot larger in diameter than the stock 15" wheels and tyres so my engine will rev less for a given speed as my car still has a 3.08 diff ratio.

[jr689]

The wheel size would also have an effect. For example a VY executive normally has 15" wheels with 205, 60 series tyres however my VY 25th Anniversary has 16" wheels with 60 series tyres which are a lot larger in diameter than the stock 15" wheels and tyres so my engine will rev less for a given speed as my car still has a 3.08 diff ratio.

Fair call, unless of course the actual rolling diameter for the tyre itself is the same for the 15" as it is for the 16"

[brodiewilson]

The wheel size would also have an effect. For example a VY executive normally has 15" wheels with 205, 60 series tyres however my VY 25th Anniversary has 16" wheels with 60 series tyres which are a lot larger in diameter than the stock 15" wheels and tyres so my engine will rev less for a given speed as my car still has a 3.08 diff ratio.

Are you sure your 25th Anniversary came stock with 60 profile tyres? i had a look on redbook and it says you should have 225/50 R16
Edit: redbook also says executives should have 205/65 R15 whick would have a slightly larger rolling diameter than your tyres

[Sean880]

I read on this site that o2 sensors have a life of around 120,000k's. I use Nulon petrol injector cleaner, one bottle treats three tanks, though I make one bottle do four or five, not keen on using it too strong, just in case it stuffs something up, even though it states that over treatment won't pose a problem.

I also use the Nulon injector cleaner. Have used it for years, in the volume recommended by the manufacturer or a bit less, on different commodores and never had an issue with it.