AU3 Economy

[boodek]

Well, after having just done a trip to Bendigo and back and averaging 7l/100km from our AU3 Futura (81,000km up, two adults and a baby, assorted gear for a weekend) and being thoroughly impressed with the car and economy, I'm wondering why the same car when driven around town like petrol is $50 a litre, struggles to reach 400km to a tank, i.e. averages about 16-17l/100km? any ideas? I've reset the ECU, replaced plugs, spoken nicely to the car but nothing seems to make a difference. Help!

[XR6-VCT-2000]

Your allways gonna get better economy on long trips , your not on and off the brake and gas pedal as much . What your describing sounds about adverage, about the same economy as i get in the city , allthough i haven't been on a long trip yet to see how low i can get it ;) .

For this model car and with the price of fuel , about all you can do to improve your economy a bit more maybe is either get it put on gas ! ..lol , or , lean off the accelerator a bit more when taking off / take off slower / don't cruise around in 3rd ( use 4th / in auto), try to judge the traffic ahead and try to avoid stoping ( like if you see red traffic lights coming on in the distance , try to slow down a de-accelerate before getting to them , hoping by the time you nearlly reach them they are green again, thus keeping the car cruising along smoothly at a sorta constant speed .

Oh , you could go for something like an edit which would sort the air/fuel mixture ratio out more , depends how much the economy really bothers you. Allthough Imo I wouldn't expect a great difference in economy from an edit anyway, this is really more of a performance mod / which with the power gains you would probably just burn more fuel again anyway ..lol

[JC]

Originally Posted by boodek

Well, after having just done a trip to Bendigo and back and averaging 7l/100km from our AU3 Futura (81,000km up, two adults and a baby, assorted gear for a weekend) and being thoroughly impressed with the car and economy, I'm wondering why the same car when driven around town like petrol is $50 a litre, struggles to reach 400km to a tank, i.e. averages about 16-17l/100km? any ideas? I've reset the ECU, replaced plugs, spoken nicely to the car but nothing seems to make a difference. Help!

I get around 15l/100km around town, and about 9.5 on the highway. So your average is about right. Can I take a guess and say that most of your city kms are short trips (less than 20 or 30km)? If so, that is the reason you use more fuel, these falcons(all 3.9/4.0/5.0 variants) run rich until operating temp is reached, and it takes at least 5 to 10 mins to hit operating temp, by which time you are already at where you were going.

[Rob]

Highway driving involves a more constant, low rev cruising style of driving, which keeps fuel consumption down, as the engine doesnt have to work like it does when accelerating, stopping and starting during city driving. As JC said, its a combination of the engine running rich to protect itself, and the fact that building up momentum from standstill costs energy - energy costs fuel.

[howesy]

All cars get pad knock to a degree, this is a term used for the slight movt. a rotor does due to wheel bearing play and rotor distortion. In city brakes are used more often and pads sit extremely close and pad knock is not so much of an issue. If your pads are stiff in their housings due to buildups etc then they may not be withdrawing from the rotor fully and causing drag. Is your car hard to roll in this situation? Pad knock on country drives has pads way and in extreme cases can reduce brake pedal due to excessive pad withdrawal. This whole issue is not overly common but enough that you should not discount it and check your pads aren't binding in the city.

[boodek]

The car is driven very economically around town (my wife and I certainly don't hoon), and yes they are short trips because Wodonga's not all that big! The point of my post is that the car is incredibly economical on the highway (obviously due to the nature of highway driving) but delivers really crap economy around town, much worse than I would expect and worse than others have reported on this forum in other posts. I went around to all of the BA-BF Falcons at work recently checking their average figures as reported in their trip computers, they ranged from 8.9 to 13.5 l/100km. I don't believe that 17l/100km is average for a sedately driven AU3. I do understand though that a cold car will use more fuel than one at operating temperature, so the question is do I have a dodgy thermostat that leaks past, or do I have a dodgy temperature sensor, or MAP sensor or any other sensor? It does take a while to warm up and when it does it sits just below the 'O' on 'NORMAL'. Is there any point taking it to an injection specialist to have it sussed out, or do I just sell it and buy something that doesn't cost a fortune to run?

[I6corp]

Originally Posted by howesy

All cars get pad knock to a degree, this is a term used for the slight movt. a rotor does due to wheel bearing play and rotor distortion. In city brakes are used more often and pads sit extremely close and pad knock is not so much of an issue. If your pads are stiff in their housings due to buildups etc then they may not be withdrawing from the rotor fully and causing drag. Is your car hard to roll in this situation? Pad knock on country drives has pads way and in extreme cases can reduce brake pedal due to excessive pad withdrawal. This whole issue is not overly common but enough that you should not discount it and check your pads aren't binding in the city.

Umm that has nothing to do with fuel ???? :

[Au2falcons]

The AU's were fitted with a thermostat that leaks past via a small hole, to gradually warm up the coolant in the radiator. Otherwise when the thermostat opens up the hot coolant floods the radiator and the plastic side tanks have a tendancy to split. I've had this happen to me (mines an AUII) it was repaired under warranty and the hole added to the thermostat. I'm sure the AUIII had the hole from factory. My AU sits on the same temperature as yours.

Since then it does take longer to warm up which doesn't help on fuel consumption on short trips. My AUII 4.0L Auto gets approx 14-15L/100km around town, today I got an impressive 6.6L/100km on a trip to wollongong which was pure freeway driving, my Mazda 6 2.3L four banger gets 7.8L/100km on the same trip.

The AU consumption is miles infront of the BA's, I owned a BA also & on the same freeway trip to wollongong the best I could get was 11.5L/100km, don't ask what to town figure was (bloody ridiculous, that's why i don't own it anymore). All figures are "at pump" calculated figures (trip computers are inacurate) and I drive casually.

In regards to selling the AU, well thats the best consumption you'll get in a falcon, I don't think there is anything wrong with it. If it's too expensive to run then you'll have to get a 4 cyl to feel lighter on the wallet. But loose the space and power of the falcon.

[Dark Horse]

Bingo Au2falcons has said it in one. You trade a engine warm up rate for preserving the radiator. AUIII's had that setup standard, so hence the increase in fuel consumption for very short trips.

As far as trading the AU in on a smaller car, will the price of the small car purchase likely offset any gain in fuel savings?

[MoreHPformyXR6]

Originally Posted by boodek

The car is driven very economically around town (my wife and I certainly don't hoon), and yes they are short trips because Wodonga's not all that big! The point of my post is that the car is incredibly economical on the highway (obviously due to the nature of highway driving) but delivers really crap economy around town, much worse than I would expect and worse than others have reported on this forum in other posts. I went around to all of the BA-BF Falcons at work recently checking their average figures as reported in their trip computers, they ranged from 8.9 to 13.5 l/100km. I don't believe that 17l/100km is average for a sedately driven AU3. I do understand though that a cold car will use more fuel than one at operating temperature, so the question is do I have a dodgy thermostat that leaks past, or do I have a dodgy temperature sensor, or MAP sensor or any other sensor? It does take a while to warm up and when it does it sits just below the 'O' on 'NORMAL'. Is there any point taking it to an injection specialist to have it sussed out, or do I just sell it and buy something that doesn't cost a fortune to run?

My BA has only done about 5500km & i heard economy may improve over time eg upto 20000km as the DOCH engines are quite tight hear's hoping (mine runs between 14.5-16litres per 100km round the city. Most of that driving is peak hour less than 10ks each way
& the car has only just reached operating temperation when I reach a multi level carpark @ work.
It gets far better economy on a trip.

[boodek]

Originally Posted by Au2falcons

The AU's were fitted with a thermostat that leaks past via a small hole, to gradually warm up the coolant in the radiator. Otherwise when the thermostat opens up the hot coolant floods the radiator and the plastic side tanks have a tendancy to split. I've had this happen to me (mines an AUII) it was repaired under warranty and the hole added to the thermostat. I'm sure the AUIII had the hole from factory. My AU sits on the same temperature as yours.

Since then it does take longer to warm up which doesn't help on fuel consumption on short trips. My AUII 4.0L Auto gets approx 14-15L/100km around town, today I got an impressive 6.6L/100km on a trip to wollongong which was pure freeway driving, my Mazda 6 2.3L four banger gets 7.8L/100km on the same trip.

The AU consumption is miles infront of the BA's, I owned a BA also & on the same freeway trip to wollongong the best I could get was 11.5L/100km, don't ask what to town figure was (bloody ridiculous, that's why i don't own it anymore). All figures are "at pump" calculated figures (trip computers are inacurate) and I drive casually.

In regards to selling the AU, well thats the best consumption you'll get in a falcon, I don't think there is anything wrong with it. If it's too expensive to run then you'll have to get a 4 cyl to feel lighter on the wallet. But loose the space and power of the falcon.

Thanks - a very useful reply.

[private9]

Originally Posted by boodek

The car is driven very economically around town (my wife and I certainly don't hoon), and yes they are short trips because Wodonga's not all that big! The point of my post is that the car is incredibly economical on the highway (obviously due to the nature of highway driving) but delivers really crap economy around town, much worse than I would expect and worse than others have reported on this forum in other posts. I went around to all of the BA-BF Falcons at work recently checking their average figures as reported in their trip computers, they ranged from 8.9 to 13.5 l/100km. I don't believe that 17l/100km is average for a sedately driven AU3. I do understand though that a cold car will use more fuel than one at operating temperature, so the question is do I have a dodgy thermostat that leaks past, or do I have a dodgy temperature sensor, or MAP sensor or any other sensor? It does take a while to warm up and when it does it sits just below the 'O' on 'NORMAL'. Is there any point taking it to an injection specialist to have it sussed out, or do I just sell it and buy something that doesn't cost a fortune to run?

Hate to break it to you mate, but what you're getting sounds about right. I've got the exact same car as you Au3 Futura (wagon) and while it's good on the freeway, around town the fuel consumption is not all that great...16-17l per 100km. Like you, my wife and I are very gentle drivers, car is well maintained etc, but that's about the best economy we can get - all I can suggest is to give the Oxygen sensor a try, (we're doing ours at the next service) but at 80000kms it's probably not that.

Like you, we were also thinking about trading, but when you factor in the poor resale of the falcons in general, as well as the changeover costs as well as the increased price of the new car, it works out to be a lot of money to save a few bucks a week on fuel....and then like others have said, you then lose the space, comfort, and effortless power that the AU has to offer :voldar02:

[HLC]

take the weights out of your right foot.

i reset the ECU on my car when i bought it and i get ~530+ kays out of a tank now. mixture of stop/start and freeway driving.

[private9]

Originally Posted by HLC

take the weights out of your right foot.

i reset the ECU on my car when i bought it and i get ~530+ kays out of a tank now. mixture of stop/start and freeway driving.

Nah, majority of our driving is short trip, so that would most likely be most of the answer!!

I will say this though, our last family barge was a VX Commo wagon with a gen 3 V8 and although the car itself was a P.O.S. it was noticeably better on fuel for the same driving than the AU 6!!

[XR6-VCT-2000]

lol , i originally got the shock horror off my life when i realised how fuel thirsty the vct is , but for how it handles / the comfort / power / its all worth it in the end ;) . Depends how much you appreciate driving nice cars i suppose . No way would i give up this fuel pig for the KA laser i was driving around recentlly ..lol ( $20 in the laser lasted a week ! ..lol , but was a horror to drive !)

[howesy]

Originally Posted by I6corp

Umm that has nothing to do with fuel ???? :

Had s**t loads to do with mine when it was identified that the brand of pad was constantly rubbing on the rotor around town and causing drag. Like driving around with one foot on the brake , not real common but still something to check when the difference is so huge in the milage.

[XR6-VCT-2000]

Originally Posted by howesy

Had s**t loads to do with mine when it was identified that the brand of pad was constantly rubbing on the rotor around town and causing drag. Like driving around with one foot on the brake , not real common but still something to check when the difference is so huge in the milage.

Very true ! . ;)

[janek]

Originally Posted by XR6-VCT-2000

Your allways gonna get better economy on long trips , your not on and off the brake and gas pedal as much . What your describing sounds about adverage, about the same economy as i get in the city , allthough i haven't been on a long trip yet to see how low i can get it ;) .

For this model car and with the price of fuel , about all you can do to improve your economy a bit more maybe is either get it put on gas ! ..lol , or , lean off the accelerator a bit more when taking off / take off slower / don't cruise around in 3rd ( use 4th / in auto), try to judge the traffic ahead and try to avoid stoping ( like if you see red traffic lights coming on in the distance , try to slow down a de-accelerate before getting to them , hoping by the time you nearlly reach them they are green again, thus keeping the car cruising along smoothly at a sorta constant speed .

Oh , you could go for something like an edit which would sort the air/fuel mixture ratio out more , depends how much the economy really bothers you. Allthough Imo I wouldn't expect a great difference in economy from an edit anyway, this is really more of a performance mod / which with the power gains you would probably just burn more fuel again anyway ..lol

lol thats how i drive in the city now, and i just barely crack 400.

highway is easy 800. that

[XR6-VCT-2000]

Originally Posted by janek

lol thats how i drive in the city now, and i just barely crack 400.

highway is easy 800. that

Im lucky to crack just over 400 around the city too , seems pretty standard for the I6 . As JC mentioned too, these cars run very rich until the car has warmed up , by which time you have usually reached your destination during short trips. Drive it like its stolen and you'll see even worse economy around the city ! ..lol . I remember when i first added a cai scoop for the standard snorkle , it helped fuel economy a bit , but soon as i added another 2 exta cai's i blew the economy out the window ..lol

[XplosiveR6]

I find the AU I6 can be quiet economical if driven easy, by letting the torque and gears do the work. but as soon as you start putting the foot down, thats when it starts drinking

[I6corp]

Originally Posted by howesy

Had s**t loads to do with mine when it was identified that the brand of pad was constantly rubbing on the rotor around town and causing drag. Like driving around with one foot on the brake , not real common but still something to check when the difference is so huge in the milage.

haha ok, ill give you that ;)