What is going on................ ANY ONE............Help

Broodie we regularly go Jurien/Kalbarri using the coast road, as we live in the northern suburbs. It is generally our preferred direction for a weekend getaway. I don't want to burst your bubble, but I don't think you've got a problem. That has to be a good thing right? We get a reasonable return for our fuel on the way up, it is always higher coming back down and a couple of times, it's been horrendous. Even when it doesn't appear windy, I am sure that it is a factor. We've not done one trip where the trip has been equal on consumption both ways.

I've never needed to tow on that road but I have noticed that the hills are a damn sight steeper and longer heading south than heading north. That may be the source of your problem.

We live in Geraldon and tow our Kedron caravan up and down to Perth (and beyond) and can tell you that fuel consumption on the south bound trip is regularly more even when we are making an extra effort to be economical. This weekend just gone was really windy and I don't think I would be wrong in saying that your fuel consumption reflected just that. Unless you actually stop the car and get out it is hard to tell that the wind is strong as there are too many trees to give you a visual indication.

We travel to the eastern states regularly and find that our consumption over there is surprisingly lower even when we travel up their big "hills". In all of our travels to the east we rarely see a 21 litre per hundred but here we would consider that good. :-)

Just spotted the probable cause of your increased fuel usage when I re-read your post. You had your cruise control set - I find that doesn't help with economy when travelling down IOD into a "breeze".

Sue

Quite possibly with that engine the car has gone into cat purge mode where it cleans itself.

If so fuel use should return to normal in couple of hundred km after its done its thing

Broodie

You have an electronically controlled diesel which adjusts it's fuel input requirements according to an electronic map covering all possible engine situations.
When travelling into a head wind there will be a considerable increase in load applied to the engine.
While relatively normal usage is happening not much changes but the ECU will adjust progressively to a load increase. This will require more power and that comes from the fuel.
Commodore cars when the VN model was made although petrol, were economical but hook up a trailer with not much load in it and the load sensing of the system made it suddenly go from 30+ mpg to 22 or 23mpg because it couldn't stay in the advanced mode it was in previously. A caravan worse still.

With the wind load you have most likely crossed the map to the power zone and and not operating in the most economic for that load.

Trying to maintain 95kmp in those conditions just demands more fuel and a little less speed would mean far better economy.
The rule I think is twice the speed 4 times the power requirements.

The cruise control will definitely not give you the best economy, your driving skill will do it better even though the auto is trying it's best. The auto, like the ECU, also has a brain which cannot match all situations either.

Your brain can.
Wise speed, no cruise, less fuel you will use.

Ross M

agree with most comments, have driven this area and north a fair bit, wind and long slow uphills will make a difference as will the coast run vs more inland route ,especially if cruise control set- it will attempt to maintain speed at expense of fuel. 95kmh a bit high for optimal fuel effeciency for a 4x4 diesel towing. other changes due to fuel load and onboard water or even food (weight) useage may contribute.
was cruise set most of the time?
Thanks,
MG

hi broodie H3
the other guys are right on the money in respect to the hills on the rd south they are long and steeper than you think
I have towed a 16 viscount up and down that rd with 2 different vehicles and the both used a lot more fuel coming back to perth than going up north
as for the wind at the the weekend you are right when you say there wasn't much
I just looked back over the wind conditions for that area on a weather site and it was around 11k's p/hr for Monday and mainly ENE
and yes on hilly rds switch off the cruise control as it forces the motor to maintain a constant speed all the way up the hill under load and will zap the fuel while doing so
cheers