AGU MAF fault/overboosting when maf connected???? HELP

[bigmarky]

Right

Posted on here few days ago regarding my AGU having running problems - http://www.golfgtiforum.co.uk/index.php?topic=223147.0

Basically ive only owned the car a few weeks, when i started running funny i asked on here and tried cleaning out the throttle body, which i dod fine, at this point the maf had been unplugged, i assumed it had just come out with me working in the engine bay and reconected it. The next day the car stared massively overboosting over 35 psi etc, i again asked on the forum and thankfully one of the guys stuck it on his vag.com, to get the readings of a faulty MAF and lambda sensor. Today i changed the MAF and tested the car, and its no different, a nice £90 down the drain  then just out of interest i unpugged the MAF again and ran the car up the road to find it boosts and normal 15-18psi etc.

Can anyone please please help starting to get a tad pissed off now lol.

[xxChrisxx]

Whats happening is that when you unplug the MAF the ECU is reverting to a default map. So everything ignores what the sensors are saying and just does what it's programmed to do with no instructions.

First things to do are free:
Check for split pipes.
Clean TB (done)

Can't think of any others that are relevant in this case.

I'd still suspect that the controller for the waste-gate is buggered. N75 I think.
What this means is that when you are getting upto a boost level, some exhaust gas isn't bypassing the turbine, causing an overboost.

[bigmarky]

We checked for split hoses when we did the vag.com yesterday and nothing was evident.

[topher]

check the actuator vac hose again. remove it completely if you have to, it can be hard to spot splits.

[stevelfc]

faulty new maf or have they sold you the right one for your car check part numbers on old and new .

[bigmarky]

Just checked all pipes/hoses connections etc, took the dv off and put it back on, unplugged and replugged the new maf a couple of times etc and took it for a run, its now hitting and staying at 22 psi only went a mile down the road and back though. Thoughts???/

[jonnyturbo]

Yep me and Mark checked all the pipes inc pcv system and all seemed fine . But like toph says take some of the pipes off to check for splits .

[james2]

you will easy see a leaking boost pipe, it will have oil on it. Forget the maf,as its new.

[james2]

bloody AGU  dont show all fault codes. 

[bigmarky]

What is the large 90 degree pipe just at the back of the engine bay behind the block to the right of the turbo and left of the intake pipe comes up and bends left into the metal pipe roughly about 3" diameter that runs at the back of the head all above the turbo (I'm no mechanic lol)