High fuel consumption all of a sudden

[splitmike]

Hi guys and girls.
Now those of you with technical knowledge please can I pick your brains.
Would you know what could cause my van to all of a sudden start using loads of fuel. I filled it up last week and the gauge has dropped to 3/4 with me only doing 93 miles. Ok they have been around town but I drive sensibly.

Ideas please!

 

[teeboy]

When we first got ours we had a lose diesel pipe in the engine compartment. At that level of consumption I would suspect a leak, especially if the fuel guage is like the one on mine it stays at 100% full for about 100 miles. I could see a leak though - is there anything underneath?

If it is doing a DPF regeneration then you can expect poor consumption for a while, but even that wouldn't be too bad - maybe 25mpg for a while rather than 30...

 

[splitmike]

I haven't seen a leak or any trace of one. It's my 3rd T5 and even this one at first started to last about 100miles before the fuel gauge moved but since I've got home this time it's shocking.

 

[Skylark2.0]

I haven't seen a leak or any trace of one. It's my 3rd T5 and even this one at first started to last about 100miles before the fuel gauge moved but since I've got home this time it's shocking.

Some thing wrong somewhere. Ask why 5 times to find the problem!

 

[motacyclist]

Possible a gauge malfunction. Fill the tank up and see how much goes in.

 

[splitmike]

I did and from the light being on it took 65 lts so it was empty

 

[motacyclist]

I've never seen the fuel light on ours, but pretty sure that more than 65 litres normally goes in at around ¼ to ⅓ full. I can check tomorrow.

Edit: Just checked now, last four fills:-

69.14 at 498 miles
72.63 at 470 miles
69.15 at 477 miles
56.81 at 387 miles (it was over ⅓ full I remember)

 

[briwy]

Cold weather, short town runs, the engine won't warm up properly so uses more fuel.
Blocked/dirty air filter??

 

[2into1]

Perhaps wasn't really full. I'd go back to a different pump and start again.

 

[splitmike]

Thanks guys I'll change the air filter tomorrow.
It was definately full I could see it in the filler neck.
I've owned the 174 and that was amazing on fuel. I guess it will be a case of trial and error.

 

[Hotel California]

I personal don't keep that much intrest in how much liter/km but sure if it drops like that it is strange.
But are you sure it was complete full at that time ....when the pump automatic stops the first time you can put in more till the edge...did you?

Did you do short rides in cold themp?

Was it that cold the engine pre-heater did work....?

All small things but could be a one time come together of all these small things

I would keep an eye on it if it does it again second time let things check in the garage.

VW did not update your software thru the emmision scandel.....?

 

[Jp277]

Is the auxiliary heater on?

My son managed to turn our one on by playing with the control panel over a weekend. When I came to drive it a few days later it was asking for more fuel and strangely warm.

 

[splitmike]

Had the van plugged into VGDS today no fault codes and no parameters were out of normal. My local vw mechanic was left scratching his head. He is also a T5 owner and is stumped. The strange part is the van still pulls like a train it runs perfectly, starts fine and idles sweet as a nut.
No heater running or left on that was my first thought. There's no leak either. Engine is dry.

 

[motacyclist]

Someone siphoning your tank?

 

[snowy55]

I did and from the light being on it took 65 lts so it was empty

The tank capacity is 80l. If you put 65l in then it was no where near empty or no where near full.
Best way to check is full to full record the milage do the maths.

 

[Hotel California]

Last time i managed to fill in 73 liter .....

 

[F5 JNR]

Does cali have 2 diesel heaters? eberspacher and a webasto? one for blown air heating inside vehicle and one for engine preheating? Our conker mpg always drops by 5-10mpg in temps below about 5 degC.