MAF knackered?

[ConorGTI]

Evening all.

I've been taking readings for a couple of days now and Im having problems, vacuum seems to sit around -8.7 at idle    G/s is around 3.5 at idle.

Max boost around 12psi, and maximum g/s was 121 from 2000-6000 rpm in 4th gear.
It runs fine for a few days and has these readings, all power drops but still get the same readings! Annoying! Anyone have any ideas?

Thanks a lot
I'm getting fed up with the car now! ☹️

[r5gtt]

Unplug it and go for a run and if it drives better then replace the maf.

Have you checked you dv lately.

[ConorGTI]

It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers

[Dan_FR]

Vcds.....

Data logging.....

I doubt it's the MAF, but it is impossible to diagnose an issue with the limited information posted above. Find somebody with VCDS who knows how to use it so they can run some logs for you

[ConorGTI]

Sorry mate I'm not sure what people need to know, do you know any body in the South Yorkshire area? Thanks

[Dan_FR]

Since I'm South Wales...... No 

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?

[lukemk5gti]

Take a look at this register to find someone nearby
http://www.mk5golfgti.co.uk/forum/index.php/topic,88875.0.html

As Dan said. Have you had your DV replaced? How to guide below:
http://www.mk5golfgti.co.uk/forum/index.php/topic,87824.msg893078.html#msg893078

I find they're very reliable cars and are very easy to diagnose but help us to help you, get it scanned, post the results here and someone will always help!

[r5gtt]

It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers

id check you dv firstly and try get some to get some logs as been said.

[pudding]

Was it holding 12psi from 2000-6000?

As the others have suggested, check the usual things - Split DV, leaking boost pipe O rings etc, update the PCV to the latest one etc.  There is nothing complicated about these engines.  All of the common post turbo boost related issues are cheap and easy to fix.

A bad MAF will usually show up at idle but your idle g/s reading is in the right ball park.  MAF will reduce as the load on the engine reduces, so we need to see some logs to analyse.  Log - MAF, Lambda, Lambda regulator, requested and actual boost pressure, requested and actual fuel rail pressure, ignition advance and the knock regulator.

[Paradox1]

It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers

id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.

[ConorGTI]

Since I'm South Wales...... No 

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?

Well that's slightly too far haha. I had the problem and replaced it with the gfb dv+ still exactly the same mate. The code I get is p0171, clear the fault then it reappears between 75-85 mile later.  Cheers

[r5gtt]

It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers

id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.

yes but he maf was unplugged sunny so it will 

[r5gtt]

Since I'm South Wales...... No 

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?

Well that's slightly too far haha. I had the problem and replaced it with the gfb dv+ still exactly the same mate. The code I get is p0171, clear the fault then it reappears between 75-85 mile later.  Cheers

you have a boost leak

[Paradox1]

It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers

id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.

yes but he maf was unplugged sunny so it will 

Thats what I just said idiot

[ConorGTI]

Chill out fellas!