MPG accuracy and playing fuel light bingo

[tboy]

Hi,

just wondering how accurate the mpg counter is, and also what is the lowest you've got to on your "miles remaining" counter. I'm sitting here at my desk waiting to go home on a 50mile trip, and the "miles" remaining is at 50 miles. Is it worth risking? Bearing in mind I'm a stubborn SOB? /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/grin.gif

PS I have a A4 TDi 130se

 

[imported_kris_tdi]

just drive slowly and that will rise up loads. i did roughly 30 miles when it said zero.

 

[rickquattro]

I put this up elsewhere, bet you dont see many of these...

 

[rickquattro]

Mmmm. Might get it right this time....

 

[tboy]

made it home!! When I left work it had dropped to 40, but I drive like a gran, got 57.2mpg, and when I filled up the range popped up to 795. Sorry to bore but having come to my A4 TDi last week frmo a Civic Type R I'm keeping a close eye on the savings!

 

[Karcsi]

It was an A8 4.0 V8 TDI!! I think the tank is about 100 litres, though. It's 800 miles there and back. I didn't think he would get as far as Edinburgh!

10 miles litre is a good benchmark - so at least 700 miles from an A4 and 550 miles from an A3. Brilliant!

 

[PeteBSK]

I've heard it's not too good for a diesel engine to run the tank too low, anyone else heard this? ..and no it wasn't my local petrol station manager that told me this!

 

[imported_Hingy]

Because of the very high compression ratio used in a diesel engine (no spark plugs, ignition is by the heat generated by compressing the fuel), if the engine runs too lean, you can melt the pistons very quickly. So if there is no fuel in the system, the engine will not start. You need to prime the fule system again to achieve normal fuel pressure before the engine management will attempt to crank.

 

[bravepilot]

Good to know... but how low do you have to run it before running that risk? /ubbthreads/images/graemlins/confused.gif

 

[Karcsi]

Sounds nasty. I knew that you have to bleed the system if you run out of diesel, but I never heard of the risk of your pistons melting. Do you know why the pistons would melt if the mixture is too lean? Surely less fuel = less energy = less heat? Or does the fuel cool down the piston as it is injected?

 

[Karcsi]

Thanks, ya big fat geek! /ubbthreads/images/graemlins/laugh_roll.gif

Good to know. I never thought that the fuel would provide so much cooling. Then again the water circulating round the block can't help too much for the piston face.

OK! Let's stop there before we send someone into a coma. /ubbthreads/images/graemlins/snore.gif

 

[bravepilot]

TOO LATE /ubbthreads/images/graemlins/snore.gif

 

[mikeA2B]

doh

 

[Andy101]

I've had an A4 Avant TDi (130) for about ten weeks or so now and have covered just over 7,000miles. Most of it is motorway cruising and have only managed to average 45mpg over the lot. I havn't got lead boots or an 'erotic' driving style.

Did it take a while for things to ease in before you started getting a return of say 55mpg as noted above? /ubbthreads/images/graemlins/shocked2.gif

 

[peteA3tdi]

my new passat 2.5 (163)only managed's 30mpg thats not much better then my S3 at 25mpg

 

[Karcsi]

[ QUOTE ]
OILBURNER said:
I've had an A4 Avant TDi (130) for about ten weeks or so now and have covered just over 7,000miles. Most of it is motorway cruising and have only managed to average 45mpg over the lot. I havn't got lead boots or an 'erotic' driving style.

Did it take a while for things to ease in before you started getting a return of say 55mpg as noted above? /ubbthreads/images/graemlins/shocked2.gif



[/ QUOTE ]

Yep. Takes about 30,000 miles for it to run in completely. Such a "low" mpg is not uncommon for a new TDI engine.

It also heavily depends on the driver. I regularly get more than by father in his A4 TDI, even though I'm more lead footed. Driving style as well as 'leadfootedness' has a lot to do with it. Don't ask. I have no idea what I do differently to my father. Could be that I anticipate traffic better.

BTW, is you "erotic" driving available on DVD? /ubbthreads/images/graemlins/laugh_roll.gif

 

[mikeA2B]

hmmm, mines just touched 30k although i was getting a good 40-45mpg even better on a motorway*, and im not a vicar either

 

[jimk04]

our 130 tdi avant will do 100 miles when the dash says 0 miles left!