Bad Fuel Economy

[DeathSammich]

I have a V6 VT commodore and it seems to be using 14L per 100km. I've checked this myself by totaling how much I drove by how much I've put in and by checking the digital readout. I've changed the O2 sensors, spark plugs, leads, coil packs, fuel pump and have a cat back exhaust (probably does nothing) a mace CAI (again probably done nothing) and have also tried 95 and 98 octane with no change. The car seems to drive fine and idle fine. Other threads ive read people manage to pull decent economy (as low as 8L long distance and a max of 12.5 mixed) but I can't seem to get these figures. I do a bit of mixed driving but I never drive in the stop start city. Thanks.

I have also checked for fault codes and I got no faults

 

[VT&VX]

That is what we get

 

[mpower]

you're using as much fuel as my V8's - is that normal!?

 

[DeathSammich]

you're using as much fuel as my V8's - is that normal!?

Yeah see my dad's 6 litre uses the same as me that's why I thought it was wrong.

 

[ephect]

Only thing not listed is MAF sensor. Try a clean or replace.

another thought is a dirty air filter

hows the trans, does it shift ok, no slippage?

 

[DeathSammich]

you're using as much fuel as my V8's - is that normal!?

I'm using the same as my dad's 6 litre V

Only thing not listed is MAF sensor. Try a clean or replace.

another thought is a dirty air filter

hows the trans, does it shift ok, no slippage?

Oh yeah forgot to mention. It has a brand new pod filter because of the mace CAI and I have cleaned the MAF sensor. Trans is fine

 

[uniacidz]

Long shot but some oils didnt like my old Falcon and had not great fuel economy and ended up using a Mitsubishi Mineral Oil 15w40

Seemed to work, got better economy

Maybe i drove it better, but did work

My current car is temperamental and only Penrite, only taken years or so to work that out

 

[FNC]

I have a V6 VT commodore and it seems to be using 14L per 100km. I've checked this myself by totaling how much I drove by how much I've put in and by checking the digital readout. I've changed the O2 sensors, spark plugs, leads, coil packs, fuel pump and have a cat back exhaust (probably does nothing) a mace CAI (again probably done nothing) and have also tried 95 and 98 octane with no change. The car seems to drive fine and idle fine. Other threads ive read people manage to pull decent economy (as low as 8L long distance and a max of 12.5 mixed) but I can't seem to get these figures. I do a bit of mixed driving but I never drive in the stop start city. Thanks.

I have also checked for fault codes and I got no faults

Hi
I drive gentle and get about10.5ltrs/100 around suburbia and about 7.8ltrs/100 on hwy (I only use 91)
I have a VX & WH (both 3.8) which I do most of the work on myself.
It sound like you have covered a considerable amount of possibles but I notice (especially this time of year with a lot of flowers out) that the air cleaner and maff need cleaning a lot more regular (maybe the pollins from flowers) If I dont clean more regular I start using more fuel. I also throw in the odd bottle of injector cleaner. The only other things I can think of would be injectors or a possible small vacuum leak. Cheers

 

[MYVESSV8]

how heavy is your foot, tyre pressures, what load do you carry all the time, oil viscosity,

 

[DeathSammich]

how heavy is your foot, tyre pressures, what load do you carry all the time, oil viscosity,

Light foot as I try to get good economy. I check the tyre pressure every fortnight to make sure it's good, weight is just me a
And the car I even removed the spare wheel and Jack, and the oil is penrite 20w 60