[Nobody Home]

Hi Everyone,

I hope someone can help.

I have an 04 407 1.6HDi and up until recently the urban mileage has been a steady average of about 200 miles per £20 of diesel. But virtually overnight it's nearly halved to 120 miles per £20.

I have changed the air filter and the fuel filter on advice from a local mechanic and also tried Cataclean and Wynns fuel additive under advisement. I have also taken the car out for a 30-mile run at high revs following advice from another garage mechanic.

None have made any difference.

Can anyone offer any advice as to what I can try next, please?

 

[noddy-hol]

Hi...does the engine sound different...does it pull well...does it smoke...tick over as it should....start normally...check for overheating brakes....its also hard to estimate mpg with such a small amount of fuel...full tank to full tank is the best way...good luck

 

[Nobody Home]

Hi...does the engine sound different...does it pull well...does it smoke...tick over as it should....start normally...check for overheating brakes....its also hard to estimate mpg with such a small amount of fuel...full tank to full tank is the best way...good luck

Hi,

Thanks for the reply.

No, it doesn't sound different, it does pull well, tick over ok and start normally. It can smoke occasionally but not often.

I don't know if the brakes are overheating; what's the best way to check for this?

There is no evidence of any fuel leaks.

I understand what you're suggesting about calculating more accurate MPG but the difference is so vast that I don't need to work out an accurate figure.:thumb:

 

[noddy-hol]

I doubt if its a binding brake but my way of testing for that is to go for a drive and feel the temperature of each wheel at the centre...they all should be fairly cool.....DO NOT TOUCH THE DISC....if one or more is binding it will be hot....

 

[Nobody Home]

The wheels are alloys. So touching them near the centre on the outside will be sufficient to test for heat?

 

[noddy-hol]

yep...

 

[Nobody Home]

All ok with the temperature of the wheels. Any other suggestions?

 

[noddy-hol]

perhaps short journeys with the air-con on low?

 

[Nobody Home]

Sorry, I don't follow. Is that a suggestion, or a possible reason for the high consumption?

 

[noddy-hol]

sorry....short journeys affects m.p.g as does air-con use.....air-con compressor uses quiet a bit of engine power to turn ..thus more throttle...not alot but enough to alter mpg

 

[Nobody Home]

Yes, I am aware of that, but my driving style and habits have not changed, only the consumption.

 

[noddy-hol]

hi..without seeing the car and doing a tank to tank test I can offer no more ideas....good luck... lets us know how you get on....

 

[WillNZ]

Get it scanned with PP2000/Diagbox for faults and also get live running data. Check things like temp readings, injector pulses, regen info etc.

 

[storeman]

Just a thought. Has the trip for that display been recently reset or the display been changed from the life history to a trip that has been recently zeroed so is no longer showing the lifetime display.