A4 b6 tdi problems


Registered User
Aug 9, 2011
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hi all,

Wounder if any one can shed any light on a couple of things.

Firstly what else can I check to find out why my 2.5tdi is boost spiking...
Iv changes map sensor,n75 and checked all lines, no fault codes replaying to turbo.... Brand new hybrid turbo fitted, as over boost killed my last turbo.

Secondly, maf sensor, I know it should y really effect boost, but I thought is test it any way, unplugged it and car still drives the exact same way as with it plugged in, also doesn't through up a light or log any codes, no limp mode niether, I drove for a good 8 miles with it disconnected.

Any help will be appreciated guys :)
Boost spikes with hybrid/bigger turbos are normally caused because the turbo is flowing more than the original turbo and isnt inline with the ecu mapping of the N75 and cant control the boost correctly, id look at getting it properly mapped.
Any one :(

Could timing cause it?

As also, turbo will boost when coming down the Rev range (engine braking)
No cats/pre cats no silencers will probably be the cause

Get your car mapped properly as you have removed all the exhaust restrictions so your std map will not be able to control the boost.

I did thae same to my A3 and turbo blew a week later due to overboosting