awful mpg-now with logs pg4 & 5

[mt audio]

Right this has been progressively getting worse and is now at the point where i need to do something. Has been doing so for the last 6 months.

I had a service the week before last of my:
oil
oil filter
spark plugs
fuel filter
air filter is going to be cleaned next week as its green cotton.
My forge dv hasnt been serviced since i had it (about 15k) so did the leakback test. Holds ok but drops to around 1cm so ive ordered a servicing kit as it seems to respond better after changing back to the oem.
However my mpg is still around 28mpg on a general run, bit of town and dual carriageway driving and i used to edge on 40mpg so clearly something is up!

I need ideas as to what to go with next. I believe its running rich as when i put my foot down in all gears i can see 5mpg which is never used to do, always used to be 13mpg in the higher gears.
I need to do a VAGCOM logs but need to know whats the best to log in order to go from there.
Any help appreciated
cheers
Matt

 

[Slimy]

My thoughts would be a MAF sensor on it's way out. If it can't measure the airflow properly it might be putting more fuel in unnecessarily.

 

[mt audio]

did a run with the maf unplugged and made no difference tbh

 

[Rocky Rocastle]

Is the heating ok ie getting up to temp.

 

[armo]

coolant sensor? iv just changed mine and what a difference on the car, average mpg is slowly but surely rising and the needle stays put a little while longer, not too mention shes much more smoother, for £8 its worth a try, if its sensing the car is colder than it is it will run rich to compensate

 

[mt audio]

its heating up fine,temp gauge runs up as it should and holds

 

[adon30]

I was going to say MAF sensor aswell. If you ran without it and it was still the same then it doesn't sound like it's working when plugged in.
Also read a thing about non OE Mafs causing economy problems. So if it has been changed, be careful.

I don't know the answer to this, but will a MAF problem show up on the engine diagnostics?? Or just plug it in and see what it throws up?

 

[LEE69]

To check the maf see what g/s it is pulling on vag com.

 

[mt audio]

thats what i wanna know.which group i need

 

[armo]

its heating up fine,temp gauge runs up as it should and holds

mine did, went up to 90 and stayed there which is why i never suspected it, but out of chance i changed it and bingo the second i did the cars 100 times better

 

[LEE69]

thats what i wanna know.which group i need

block 003

http://www.ross-tech.com/vag-com/m_blocks/001-009.html

 

[mt audio]

mine did, went up to 90 and stayed there which is why i never suspected it, but out of chance i changed it and bingo the second i did the cars 100 times better

In that case i shall order one after logging it to see if its at fault for anything.

block 003

http://www.ross-tech.com/vag-com/m_blocks/001-009.html

Thankyou. Shall report back once checked

 

[jonesy118]

Vagcom logging.. I know you start at 2000-2500 and go to redline in 3rd/4th gear, but does it make any difference if you go progressively, or is it foot to the floor?

Never done any logging, only adaptations and fault codes..

Need to see what g/s I'm pulling on standard map with TIP and Jetex, got a feeling my maf is dying.

 

[armo]

deck it so that the throttle body is wide open and sucking in as much air as you can get

 

[Slimy]

Yep, foot to the floor as soon as possible, as long as you can keep traction. Bear in mind that second gear is the highest gear that can be legally revved out...

I did once try and do a log in first gear, but it revved out so quickly I only got two samples! Even in second gear I struggled to get any more than a handful of samples, I had to redo the run to get a bit better results.

 

[Rocky Rocastle]

ideally you need to do 4th gear runs so you can get a max load run, 3rd is ok but fourth is better.

Must admit i dont like logging

 

[adon30]

Do you need full version of VAGCOM to do logging? or can you do it on the lite version?

 

[edwardmonkton]

lite version should do the trick I think

 

[mt audio]

havent done a proper run yet but after 30mins of driving the highest temp seen from the coolant temp sensor on vagcom was 72 degrees and the dash wash reading 85/90 so its clearly had it. New one ordered. Once that is on and changed ill get on with the logging as there is no point whilst thats duff

cheers peeps

 

[armo]

told ya lol, wait until you replace it, the difference shocked me mate, your fuel needle will stay still alot longer as the car will stop overfuelling. When i pulled the sensor i got a 3ft fountain of coolant shooting into the air, my face, and my mouth, so just go easy lol it tastes like ****