Complete boost failure - help

[dan_b]

Oh dear. Cleaned my MAF with IPA (to try and see if that would improve the rich-running I've been getting) and re-attached it yesterday. Made damn sure it was connected properly. Drove it last night and

Once the turbo spools up with anything approaching 1/2 throttle and above 3000rpm, I get a huge whooshing/sucking noise which is accompanied by the car lurching and doing the opposite of accelerating.

I've either killed my MAF, or I've got an air leak which co-incidentally has just appeared, or both.

Please can anyone in West London help with checking out my MAF, doing a VAGCOM and also a boost leak test?

[Fat Audi 80]

Are you sure you have your MAF back on correctly? It sounds highly likely you have not connected the pipes up correctly again and introduced your own boost leak. YOu have not damaged the wire have you.

Does it drive perfectly off boost but badly as the pressure builds?

Cheers,

Steve.

[mcandmar]

whooshing/sucking noise would suggest a leaking hose to me. I was under the impression they wouldnt idle if the maf was broken, i know our S4 wouldnt idle with a cracked intercooler due to the airleak.

[dan_b]

I will double check the MAF but I'm sure I connected it back ok, but it does seem too much of a coincidence to not be related. I really hope I've not knackered the MAF. It seems to drive pretty normally off boost, although the economy is even worse than normal.

Be careful cleaning MAFs!

[AAH!]

when fiddling with the MAF to turbo hose something may have come loose on it, like the DV or WGFV or even the connection to the turbo. Just do a quick check through all the connections in that area, I'm sue it is something simple like that.

[A80Avant]

why do i think that what you are describing is a safe mode action?I had it when i had a small crack on a small hose but couldnt hear the whoosing in my case because the leak was hose was too small,either the crack was too small.Either way,i did end up in safe mode.Sound like something wrong that you did with the maf.It is going to be quite a coincidence if you have a boost leak now!

[s2driveruk]

If you're running rich you sure the lambda is ok? mine was really sucking through fuel and i ended up changing that and it cured it.

When I drove off without my maf connected it just lurched and wanted to keep trying to stall....

[dan_b]

Lambda is less than 12 months old and is fine, I've not been getting the "surge/ hesitate lumpy tickover" symptoms that I got when the Lambda was dead before. Once Cameron stops crying and goes to sleep I'll venture outside and check the plumbing around the MAF...

Anyone able to drive round and give me a quick VAGCOM?

If I've got any split hoses, are there any SAMCO boost kits going?!

[alg]

Be careful cleaning MAFs![/QUOTE]

I would agree with Angus re checking 'to turbo hose'. Also if it appears well connected have a good look for splits. If its original it may have split with age during the MAF removal/refit.

Now onto MAF cleaning. Good idea for contaminated (e.g. aftermarket air filter users) wires but how does alcohol remove 'baked on age related crap' as a result of the wire cleaning process (heated post run to remove contamination).

Just a friday thought

[dan_b]

took MAF and filter off and re-fitted taking care to examine all pipes in area. No signs of any splits or holes. Re-fitted MAF made no difference - the car basically dies when boost comes up accompanied by huge sucking sound. Actually the car isn't running particularly great off boost either, slightly hesitatant to pick up revs after a gear change.

I've looked at my MAF wires - they're all intact, but they're totally brown. What's happened there? It almost looks as if they've rusted? Surely putting it in IPA should have cleaned them? What metal are they made of, platinum isn't it?

Can anyone help me by popping round with their S2 and checking the MAF or plugging me in to VAGCOM?

[alg]

I would get a new MAF Dan. My MAF wires were nice and clean, silver on the unit I replaced.
Just a final thought, did you submerge the whole unit ?

[PeteRR]

I too found that IPA wont even touch the brown discolouration of the MAF wires. They just seem to get like that after a few years.

As well as the usual suspects, try Pete at www.quattrocorner.com for a price if your thinking of a new MAF Dan.

[s2driveruk]

dan I would have said I'd blast up the M3 but I'm on a conference call and need access to my pc...sorry mate.

Have you checked the jub clips all over, especially the ones on the little metal elbow, mine boosted and clean brokea clip there in two a year or so ago twice in as many weeks

[dan_b]

I checked the tightness on all the jub clips I could see on all the big and small bore hoses they all seemed fine.

I submerged it up to the level of the top of the wires in the tube - I didn't let the grey control box on the top get wet at all. Just wondered, if I got a q-tip in IPA and a very gentle hand indeed, do you think I should have a go at cleaning the wires directly, that brown colour doesn't look right?

[mcandmar]

I used a can of carb cleaner instead of IPA, figured it would be better for removing carbon buildup and oil. Did you make sure it was completly dry before refitting? I used a hairdryer on mine to be sure. The brown colour dosent sound right though.

Only other suggestion i can think of is the wiring, i've heard of 7A's giving trouble when the wiring goes dodgy on the MAF plug.