Fuel economy 2nd tank

Davoe,
did you fill the aux tank at gull before the trip, your thread indicates you did. If you didn't there could be a couple of reasons,
old fuel or bad fuel.

After that I can't give a reason except for head winds, altitude, rain, temperature or speed as you say the there wasn't much difference in the roads.

I have had the same thing happen recently on a 3500k trip.

Was running between high 11s to high 13lts/h, then one load of fuel went in the mid 15s for no apparent reason. Not much changed ie: road conditions or speed except some of the other readings came from slow 4wd through the scrub and did not change the fuel much.

You didn't say if you have checked your fuel usage after the trip.

Have a safe one

The Ape

This happened to me twice on my latest 4 month trip and I have only one explanation that I can come up with - we've been done.

I know it sounds drastic but it does happen. I couldn't explain it any other way when it happened to me. By way of example read on:

On our last trip away, I was in Kunnunarra using the car wash at the Shell and had to get some dollar coins for the slot. So I'm stood in queue waiting - and a VERY big queue it was. There musta been about 30 people waiting to pay for fuel.

At the head of the queue there was a guy refusing to pay for his diesel as he reckons his tank only held 85 litres and the pump siad he took 100 litres. I can't remember what vehicle it was - mighta been a Prado or something like that - but he was adamant and ropeable that he was being overcharged. When this happens, all ya can do about it is to pay for the fuel and then write to Shell and ask them to check it out. If you're right, you get the overcharge refunded. If ya drive off without paying then you become guilty of stealing.

The guy at the till was doing a mighty job under a lot of pressure, insisting that he couldn't give the guy a refund and he would have to contact Shell. People in the queue were getting a bit wound up with this customer saying,"He's told ya what to do about it, now MOVE!"

It happens

Bilbo

Davoe,

Not sure if the system in the diesel is different from the petrol, but my 80 runs the tranfer pump for a few seconds after startup. Over time this has the effect of giving better 'economy' from the main tank and poorer for the sub-tank. Gets more noticeable with lots of stopping and starting which you probably weren't doing anyhow.

Matt.

I don't know the reason, Davoe, but I noticed the same thing a couple of months ago (80 series diesel) and at first thought it was the station I was filling up at. But over a couple of months I've consistently used an extra litre per 100km on the sub tank. I've eliminated all the variables like where I fill up etc; it's got me baffled.

You don't say what vehicle you have so I'm guessing 80 series deisel. When I fill mine (sub tank) the flap doesn't close off the main tank completly so some of the fuel goes into the main tank.
If I use just the sub tank then fill it it holds about 40lt and the main tank about 80 lts.