Aum jerky boost

[reedy20vturbo]

Right, i recently brought another new maf from tps because I seem to have a very annoying problem I can't seem to figure out, with the maf disconnected the car runs like a dream apart from being a little hesitant when cold, with the maf connected it runs like rubbish, low then suddenly high boost, sometimes no boost, very very jerky part throttle, you can't accelerate smoothly it's either no boost or full boost, when you pull away it dumps boost and I've not even lifted off the pedal, so I brought a new maf and it's made no difference so now I'm confused in what else could be causing this? I've plugged it in and I have a few codes system to rich bank 1 add, 2 codes because of my decat and now the 17705 code has appeared pressure dropped between throttle body and dv, any help will be much appreciated

[WadGTI]

Double check for vac leaks and check the pancake pipe as it could leak at the weak joint going into the intercooler.

If you have vagcom, I would be logging the maf as the maf may still be faulty (assuming it was a refurb you bought from TPS?).

Personally, it took the 3rd repalcement bosch maf for it to work proper for me. The others I bought as per vagcom were not reading enough air but not thowing any codes.

[reedy20vturbo]

I will check for leaks again this week, I just don't understand why it would run so well with the maf disconnected? This is its 3rd maf but thus time it didn't make a difference, last time it would run ok ish for about 2 or 3 days then it would slowly come back, I'm not sure if it was refurbished but I asked for a new one, it cost me 90 quid and I swapped my old one in, it makes driving the car such a pain because it runs like that, I recently added a catch can with all new pipes and that hasn't made a difference, thanks for your advice

[Mr_Orange]

Catch can before or after running problems?
Have you checked dump valve function or N75?
Been able to scan for codes?

[reedy20vturbo]

It was doing it before I put a catch can in, and it made no difference,  I have a forge 008 valve witch was new about a year ago, not sure how to check n75? Yeah couple codes I mentioned in my first post

[WadGTI]

if it is running fine without the maf connected, then i would say too deff log the maf (block 003...i think), take it for a run, wide open throttle and have a look at the results. You will be able to see stright away if the maf is recording the right amount of air.

I take you have the standard airbox, etc.

[reedy20vturbo]

Ok I will try that, I have a honda s2000 filter but it was doing it before I put it on, the reason I'm starting to think it's not the maf is that I've tried 3 new mafs and 2 used and theyve all done the same thing

[Chris.]

maf unplugged can disguise a shed load of issues.

If you ahve VCDS, log boost specified vs actual and wastegate duty cycle.  Also fuelling.