MPG wrong on dash (ecu tweaking needed?)

[Antimus]

I've got my octy booked in with you guys for the 12th for a new hybrid turbo, and I was wondering if you could have a look at the mpg indicator at the same time. It constantly shows the wrong MPG. at 45MPG real the display shows around 50MPG.

I'm not going to be able to do a full tank comparison before I drop it off though as I'm trying not to drive it much.

Also while you're fiddling with the ECU are there any other settings you can make to improve or add features?

For instance I'd love to get rid of the 2 click to unlock all doors.

Edited 31 August, 2011 by Antimus

[Antimus]

I'm feeling the cold shoulder of ignorance :(

[shark_90]

Hi Dan, we're pretty busy in the office and we try to get back to forum posts as quickly as we can but it's not always something we can do immediately.

[Antimus]

okie dokie. I forget you're batsh*t crazy over there with the move and all, sorry!

[Antimus]

So I can probably get 3/4 of a tank used before I drop the car off on Saturday, which should give a pretty accurate MPG read. Are you able to fix the car's MPG display?

[Gizmo]

So I can probably get 3/4 of a tank used before I drop the car off on Saturday, which should give a pretty accurate MPG read. Are you able to fix the car's MPG display?

Without trying to step on Shark's toes he's good but cannot do the impossible:

To make your consumption read accurate you need to do some accurate checks yourself first.

Brim the tank (I wait for the pump to click off 3 times, waiting a couple of seconds between the pump clicking off and re squeezing the trigger - do not pull the nozzle out of the filler at all though) record the mileage, reset the car's average consumption (No.2) and use the full tankful.

Refill the car exactly as you did previously and note the mileage covered and litres used, use these figures to work out the true MPG of the car AND note what the car's computer reads.

Only when you know these fugues can anyone have a realistic chance of making the car's figures more accurate (mine are within 0.1 MPG each tankful)

HTH

[Antimus]

Without trying to step on Shark's toes he's good but cannot do the impossible:

To make your consumption read accurate you need to do some accurate checks yourself first.

Brim the tank (I wait for the pump to click off 3 times, waiting a couple of seconds between the pump clicking off and re squeezing the trigger - do not pull the nozzle out of the filler at all though) record the mileage, reset the car's average consumption (No.2) and use the full tankful.

Refill the car exactly as you did previously and note the mileage covered and litres used, use these figures to work out the true MPG of the car AND note what the car's computer reads.

Only when you know these fugues can anyone have a realistic chance of making the car's figures more accurate (mine are within 0.1 MPG each tankful)

HTH

Thanks for the info, but I've done it before hence why I know my car's readout is about 5MPG out from true.

The reason I've said I can get a 3/4 of a tank read is as stated on the first post, trying to keep the usage to a minimum until Shark have swapped the turbo out. Unfortunately bare minimum became work saying "can you drive to Leeds on Monday" which added some miles.

The MPG readout must work on some kind of equation in the ECU which is most likely incorrect on my octy, which does surprise me as I can't believe it's been 5MPG out since new, the only other explanation is for some reason my car is running 5MPG less efficiently than when new, but how could that be?

All guesswork, I don't even know how it tells how much fuel has been used :wonder:

[TrevorB33]

Thanks for the info, but I've done it before hence why I know my car's readout is about 5MPG out from true.

The reason I've said I can get a 3/4 of a tank read is as stated on the first post, trying to keep the usage to a minimum until Shark have swapped the turbo out. Unfortunately bare minimum became work saying "can you drive to Leeds on Monday" which added some miles.

The MPG readout must work on some kind of equation in the ECU which is most likely incorrect on my octy, which does surprise me as I can't believe it's been 5MPG out since new, the only other explanation is for some reason my car is running 5MPG less efficiently than when new, but how could that be?

All guesswork, I don't even know how it tells how much fuel has been used :wonder:

are you running standard size wheels?

[Gizmo]

I can't believe it's been 5MPG out since new, the only other explanation is for some reason my car is running 5MPG less efficiently than when new, but how could that be?

TBH I am not surprised it reads 5mpg out, I have corrected my Superb and 2 Yeti's that were also about 10% out, (meaning 4.5 - 5 mpg optimistic)

There are also several other members on here who report their cars have an optimistic average mpg on the MFD when compared to actual mpg.

[shark_90]

If you do know how far it's out then it's something we can correct

[Antimus]

Cracking

I just stumbled on a resurrected thread that says how to do it in vag-com on the octy2 forum, seems simple enough.

I'll note down the actual mpg and what the display showed when I drop it off, that should be all you need to work out what the % difference is.

oooo less than 2 weeks to go...

[Antimus]

how's mah car?

[shark_90]

Physical work done, mapping starts today

[Antimus]

[Antimus]

Thanks for the work guys, loving the new power (getting used to the extra lag now I believe) and thanks to Ben for coming in on a Sunday to get it finished

Not sure when I'll be able to get the car back down for the MPG change, not got many weekends free for a while.

I also remembered about the immobilizer code from another thread somewhere, but given any work needing it would be done by you guys anyway that can wait.

Will be in touch for future work I'm sure!

[shark_90]

Glad to hear it See yo soon

[Antimus]

I'll have a bit of time on Saturday morning if that's a good time to drop by and get the tweak done. My day opened up thankfully.

If that's ok with you guys what time do you open?

[shark_90]

I'll have a bit of time on Saturday morning if that's a good time to drop by and get the tweak done. My day opened up thankfully.

If that's ok with you guys what time do you open?

I'm afraid not as we'll be at Audi Driver International at Castle Combe. Please give the office a call to find a time to come in

[Antimus]

I'm afraid not as we'll be at Audi Driver International at Castle Combe. Please give the office a call to find a time to come in

Damn, ah well have fun!

[Wardy]

Without trying to state the obvious, if you've done your sums and know what the percentage difference is, then anyone with VCDS can alter this for you...

[wja96]

Without trying to state the obvious, if you've done your sums and know what the percentage difference is, then anyone with VCDS can alter this for you...

On a Fabia? I thought it wasn't straightforward on the Mk I, but the Mk II Octavia etc. there are loads of guides.

If you know how to do I on a Mk I could you post up the controllers and coding as I'd love to have this fixed. Mine over-reads to a stupid amount.

[Antimus]

I know, but the only vag-com owner on the forum near me (robnemma) never replies to messages, the closest after that is Sheffield and it's actually quicker to drive to Mansfield than it is to get to the other side of Sheffield

[Wardy]

On a Fabia? I thought it wasn't straightforward on the Mk I, but the Mk II Octavia etc. there are loads of guides.

If you know how to do I on a Mk I could you post up the controllers and coding as I'd love to have this fixed. Mine over-reads to a stupid amount.

I was meaning Antimus' Mk2 Octy, but I did tweak my accuracy my Fabias when I had them. The difficult bit is remembering where it's stored though, as that was some time ago and I've not been asked about it since

[Antimus]

I've got the location for the OctyII on a forum bookmark at home, not sure of the Fabia location though, sorry

[wja96]

I was meaning Antimus' Mk2 Octy, but I did tweak my accuracy my Fabias when I had them. The difficult bit is remembering where it's stored though, as that was some time ago and I've not been asked about it since

Understood. My mistake (getting a bit hopeful!). I'll get Shark to do it when I book the Fabia in for it's turbo swap.