Suddenly using more fuel

[Nanook]

Check the simple things first like whether the fuel line has a leak. It may only leak under pressure so you might not notice a puddle of fuel underneath.

My old Holden Frontera was doing the same thing for months and I found a clamp on the fuel line just needed tightening.

[Rubicon Azza]

Originally Posted by Nanook

Check the simple things first like whether the fuel line has a leak. It may only leak under pressure so you might not notice a puddle of fuel underneath.

My old Holden Frontera was doing the same thing for months and I found a clamp on the fuel line just needed tightening.

Good Point!

Had a few thoughts of that.
I will get that checked out.

I took it to get an alignment yesterday and they said that the front wheel bearings were out.

Making tires point outward.

Hopefully it's that but I am going to check fuel lines too.

Thanks!

[Nanook]

Originally Posted by Asdren

I took it to get an alignment yesterday and they said that the front wheel bearings were out.

Making tires point outward.

That would definitely increase your fuel consumption.

[Rubicon Azza]

Ok done alignment and chnaged oil to 5w20 instead of 5w30.

Spark plugs were buggered.
The fuel economy is starting to normalize.

I think the spark plugs were doing the damage on the fuel consumption.

[humdingerslammer]

OK. Here's my input. Pretty much standard JKU Rubicon.

My 07 JKU Rubicon drinks fuel like a lapsed alcoholic. The best it ever did was with a tail wind on a flat road (across the Nullarbor) at 100km/hr. The computer was saying 8km/litre. It was a really strong tail wind: blowing a gale really.

I calculate consumption on the basis of Km done and litres to fill the tank. I don't rely on the computer for accuracy. In reality around town I get about 5.5 km/litre and I get between 4.8 and 5.5 towing a trailer or caravan. I have learned to live with it. Weight in the vehicle or being towed, head winds and speed make all the difference in fuel consumption when driving a brick on wheels! So does going up or down a hill. I find I have to use the gears to keep up momentum.

The commonest con by mechanics etc that leads to increased fuel consumption is the failure to replace spark plugs or to replace them with the correct type but to charge for it as if it has been done. From memory the JKU came out with long life plugs and if these r not changed then fuel efficiency will suffer. I don't use them and I change plugs at every 40000 km. Much more reliable result and about the same cost.

I also think it is important to change air filters regularly and to use the correct oil viscosity. I stick to the standard OE air filters because they are actually very good. K&N filters are touted as better because they let in more air but the ECU will reset itself and actually add more fuel to the mixture (paradoxical I know). Also K&N filters let a lot more shit and dust into the fuel system when u r about in the deserts etc.

It is also good to completely empty the fuel tank from time to time prior to refilling to get rid of any water in the tank and to use additives that will help this process.

Hope this helps

[Rubicon Azza]

Originally Posted by humdingerslammer

OK. Here's my input. Pretty much standard JKU Rubicon.

My 07 JKU Rubicon drinks fuel like a lapsed alcoholic. The best it ever did was with a tail wind on a flat road (across the Nullarbor) at 100km/hr. The computer was saying 8km/litre. It was a really strong tail wind: blowing a gale really.

I calculate consumption on the basis of Km done and litres to fill the tank. I don't rely on the computer for accuracy. In reality around town I get about 5.5 km/litre and I get between 4.8 and 5.5 towing a trailer or caravan. I have learned to live with it. Weight in the vehicle or being towed, head winds and speed make all the difference in fuel consumption when driving a brick on wheels! So does going up or down a hill. I find I have to use the gears to keep up momentum.

The commonest con by mechanics etc that leads to increased fuel consumption is the failure to replace spark plugs or to replace them with the correct type but to charge for it as if it has been done. From memory the JKU came out with long life plugs and if these r not changed then fuel efficiency will suffer. I don't use them and I change plugs at every 40000 km. Much more reliable result and about the same cost.

I also think it is important to change air filters regularly and to use the correct oil viscosity. I stick to the standard OE air filters because they are actually very good. K&N filters are touted as better because they let in more air but the ECU will reset itself and actually add more fuel to the mixture (paradoxical I know). Also K&N filters let a lot more shit and dust into the fuel system when u r about in the deserts etc.

It is also good to completely empty the fuel tank from time to time prior to refilling to get rid of any water in the tank and to use additives that will help this process.

Hope this helps

Fucken oath it does.
I have a jku with 46k on the clock and know now that should replace sparks at 40k.
Using thicker oil doesn't work, even though everyone said it does.
5w20 works better than the 5w30.
And yes I did run a K&N, didn't see a benefit and wont buy another one.

Thank you for the reply, much appreciated.

Question though,
What about upgrading the radiator or even putting in a thermostat that kicks in the cooling earlier?

[Banshee]

I don't think a lower temp thermostat would help. I do not believe that the temp difference would be significant. If it made any noticable change, it would be for the worse, however, as you are losing more energy to the cooling system.

IC engines are most efficient running as hot as the materials can stand. (More energy from the hot expanding gas, to push on the piston, rather than it being lost to the cylinder walls, cooling the gas & lowering the cylinder pressure.)

If your engine is overheating, though, a better rad would be the way to go. But if you aren't, then it won't help either.