VCDS diagnostic functions for MAF sensor operation.

[Charlie Farley]

Posted this question on this B7 section really as it's for my B7 and there maybe a specific vcds set of functions that need accessing for me to check the situation.
So then having managed to sort out all the previous error/faults etc in vcds , I now have an error / fault free car, well for the time being that is.

My question now is regarding the MAF sensor operation or possible lack of correct operation.
I cleaned it last Friday with a recommended spray as it was filthy , next day I had a whole raft of electrical gremlins plague the car, maybe connected or not I couldn't say for sure but just strange that they all occurred the next day the first time I started the car after cleaning the MAF.

Anyway, there are no current faults for the engine or MAF but the fuel consumption since cleaning the MAF has dropped through the floor, urban MPG has dropped too but the onboard computer maybe misreporting data or it was prior and now its closer to actual consumption.
As no fault is being reported I don't want to be lashing out on a new MAF at around the £100 + bracket if it's working within specs.
I was under the impression I could view the correct parameters in vcds to see if it was running within tolerance but thus far I cant find any section with the info , that is of course its viewable in vcds.

If anyone has knowledge of how this can be done or even if it can be done please can you advise on the procedure as I really need to get to the bottom of things , either to discount the MAF as its working or if its failed and I can organise a new sensor.
Any input would be very greatfully received chaps.

rob

 

[Paul battams]

Hi Rob
You can view MAF readings in measuring blocks think it’s 04 on left hand side then just scroll through not sure on the number.
I’ve just sorted a fault out regarding MAF and other stuff it was fuse 31 15Amp that was my problem but mine is a 3.0tdi
Good luck


Sent from my iPhone using Tapatalk

 

[Charlie Farley]

Well to be honest Paul i'm wondering if the MAF is failing.
Just been out for an hours general driving , urban and some open country roads , not pushing it though and not braking hard either.
The MPG on the dis settled down after 10 mins to between 24 mpg and 30mpg based on the roads and driving, I know the dis figures are not 100% accurate but seem to be correct compared to figures below.
Also the cars mapped with HFC , larger down pipe and performance air filter and its a quattro.

Fuel consumption

simulation based on the European type of traffic



(mileage)

extra-urban / city / highway / average combined:


l/100km:

7.5-9 / 12.8-15.4 / 8.6-10.3 / 10.4

mpg (imp.):

31.4-37.7 / 18.4-22.1 / 27.4-32.8 / 27.2

mpg (U.S.):

26.1-31.3 / 15.3-18.4 / 22.8-27.3 / 22.6

km/l:

11.1-13.3 / 6.5-7.8 / 9.7-11.6 / 9.6


Comparing to the MPG Imp range mines about normal, I suppose its possible the maf was misreading being so crudded up that now it's correct it seems wrong, if you get my drift.

 

[i3oricua]

Block 003 but you should log it along with block 115 (to log boost) so that you have an RPM range to assist in the measurement. I don't know what a chipped K03 should be reading but I think you should be getting around 150 - 160 g/s at full boost. Try logging 3rd gear, 2000-6000 and an empty, safe stretch of road if you can. I'll see if I can find some info that suggests what you should be reading at.

 

[Charlie Farley]

cheers chaps, knew I could rely on help from you all.
don't have time now to run vcds so will have a go tomorrow morning.

 

[Charlie Farley]

Small update on this possible problem area, pulled the plugs this morning and all looked fine , no sign of overly rich running.
MPG has settled down again and seems about right , well based on published data , I wont get those figures as the car is not in standard tune .
Going to give vcds a try tomorrow as the laptop I use died yesterday and only just got it restored this evening....
Maybe things are looking up for the old bus now, I hope so.

 

[Sygh2k]

Theres a lot of values here which may help you
https://www.audizine.com/forum/showthread.php/495049-Post-you-MAF-max-values

 

[Charlie Farley]

many thanks chap, some good info there for me to work with, hopefully the laptop wont fail now so I can get some data logging done on it.

cheers chaps.
rob

 

[Tdibooster]

Waste of time cleaning mafs . If it's bad replace it. Too many times I've seen folk cleaning them out and makes them worse