forum.audiv8.com Foren English Audi V8 Forum suddenly very high fuel consumption

Most of my injection knowledge goes as far as K-Jet, so Lambda and EFI issues are newish.

On a recent journey, after several hours of normal fuel consumption which would nominally be around 26-27mpg, consumption increased to below 20mpg at normal cruise speeds/RPM. on gentle load increases, what would be around 15-19mpg has gone down to 8-9mpg.
Once this started happening, occasionally, would return to normal, before increasing again.

Is this a attributable to Lambda? or something else.
I'm a little stuck for running diagnostics at present.

Do you have any possibility to readout ECU fault codes?

May be the Lambda, but it's also pretty common that the G62 (engine temperature sensor on the back) is faulty. Easy to replace and quite cheap afair.

Bastian

Sadly, my diagnostic lead disappeared. so i have to make a new one.


temp sensor.
Thanks, I'll take a look.

funnily, the car has been running hot in slow traffic recently, and indicating hot. The fan doesn't come on at all.
could that be related? (I thought it was controlled by a sensor on the rear left bottom of the rad)

Hi,

no, the fan control is performed by the dash instrument cluster and this, in turn, gets the temperature information from the sensors in the front, one in the cooler and the other one nearby the intake manifold, where the water hose is mounted.

But after 25 years, not only the cooler but also the sensors are usually worn out. Most V8s have more than one of those sensors broken at some time. The RHD we bought in the UK 2004 had several temperature issues, as far as I remember...

Regards

Bastian

Click me - im tell you how to read out the fault codes

and watch the attachment, by automatic-transmission you need no bulp - just a bridge.

Unless I'm mistaken, that works on the LHD cars, but not the RHD.

I found my previous test lead, but I have no time now until April! damn

Why not to RHD?

Unless I am mistaken, the procedure either needs-

VAG Test box/VagCom
Test lead (mine wasn't available at the time)
Check engine light. The RHD car doesn't use a right hand version of the left hand cluster. I may be wrong. Bastian has had some dealings wight he right hand drive cars, too.

Mistaken or not... do you allready try it? no? go on...

Not this year.
A while ago, but I ran out of time this year.