MPG display zoroes then rises

[richdubya]

Mk4 2000 MY 1.8T 150bhp remapped 3 years ago.
I recently used the car on the motorway and noticed the MPG indiactor was "hunting" it zoroed out then seemed to reset itself, then slowly climed up to 200mpg the started to drop back down to around 9mpg then back up again. It did this when i came off the motorway too but the mpg did not have such a great high to low range. I have tried a few ignition cycles and the problem persists. I do not yet have any diagnostic equptment (but can borrow a basic tool)so have no dtc's to post.
Any ideas folks before i go any farther???

[Rhyso]

firstly welcome 

2ndly - press the rocker button on your wiper stalk to cycle through you trip computer 

3rdly - stay and enjoy the forum 

4thly - read your owners manual if you have one 

[richdubya]

yes someone mentioned the stalk reset to me today, i will consult the owners manual, just thought it was unusual for this to happen.
thanks.

I read the manual and did a stalk reset, now all is well. It does pay to read the manual. CHEERS
Ive not had the car long and it did seem unusual.

[Rhyso]

yes someone mentioned the stalk reset to me today, i will consult the owners manual, just thought it was unusual for this to happen.
thanks.

you have several options in the trip computer 

the one you stumbled across is you instant MPG so it works out roughly how much fuel you are using depending on throttle position, speed, engine load etc etc

the computer resets 2 hours after the ignition is switched off although if you have a 2 in the corner this is your long term computer and resets after 99 hours and 59 minutes of driving

[dubcruiser]

yes someone mentioned the stalk reset to me today, i will consult the owners manual, just thought it was unusual for this to happen.
thanks.

you have several options in the trip computer 

the one you stumbled across is you instant MPG so it works out roughly how much fuel you are using depending on throttle position, speed, engine load etc etc

the computer resets 2 hours after the ignition is switched off although if you have a 2 in the corner this is your long term computer and resets after 99 hours and 59 minutes of driving

Rhys, your just a wealth of knowledge!!! 
I never knew the Number 2 comp programme reset after 99 hrs!! That explains why my long term mileage on it zeroed then! 

[Rhyso]

yes someone mentioned the stalk reset to me today, i will consult the owners manual, just thought it was unusual for this to happen.
thanks.

you have several options in the trip computer 

the one you stumbled across is you instant MPG so it works out roughly how much fuel you are using depending on throttle position, speed, engine load etc etc

the computer resets 2 hours after the ignition is switched off although if you have a 2 in the corner this is your long term computer and resets after 99 hours and 59 minutes of driving

Rhys, your just a wealth of knowledge!!! 
I never knew the Number 2 comp programme reset after 99 hrs!! That explains why my long term mileage on it zeroed then! 

cheers Scott  nice to know my knowledge is somewhat useful 

the No2 trip is useful for working out your proper long term MPG (if you're into that sort of thing  ) and will actually closely match your fuel consumption per tank 

[Dubbz]

As this is in discussion, how many of you reset the trip after a short journey?
If i drive for say 7ish miles stop the motor leave it for an hour then get back on the road, temp gauge reads 90 and trip 1 says 41mpg.
Reset to zero do the same journey back it'll reach 60mpg easy?  
Anyone done this? I'll assume its a false reading?

[Rhyso]

As this is in discussion, how many of you reset the trip after a short journey?
If i drive for say 7ish miles stop the motor leave it for an hour then get back on the road, temp gauge reads 90 and trip 1 says 41mpg.
Reset to zero do the same journey back it'll reach 60mpg easy?  
Anyone done this? I'll assume its a false reading?

yep its a false reading really as your car is up to temperature in no time at all so will give you a much improved MPG figure 

[Dubbz]

As this is in discussion, how many of you reset the trip after a short journey?
If i drive for say 7ish miles stop the motor leave it for an hour then get back on the road, temp gauge reads 90 and trip 1 says 41mpg.
Reset to zero do the same journey back it'll reach 60mpg easy?  
Anyone done this? I'll assume its a false reading?

yep its a false reading really as your car is up to temperature in no time at all so will give you a much improved MPG figure 

Bugger!  makes me feel better tho watching it at 60mpg lol

[Rhyso]

As this is in discussion, how many of you reset the trip after a short journey?
If i drive for say 7ish miles stop the motor leave it for an hour then get back on the road, temp gauge reads 90 and trip 1 says 41mpg.
Reset to zero do the same journey back it'll reach 60mpg easy?  
Anyone done this? I'll assume its a false reading?

yep its a false reading really as your car is up to temperature in no time at all so will give you a much improved MPG figure 

Bugger!  makes me feel better tho watching it at 60mpg lol

lol

i do it sometimes if my car has been into the garage and been left idling or taken out for drive around the block (dread to think how they actually drive it mind!)