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View Full Version : No boost, checked N75 and weird thing happened, need opinions



Avantium
10-04-2011, 04:58 PM
Virtually no boost for 3 days now (maybe 3 psi - can hear blowoff valve just barely), i cycled the key - nothing, unhooked battery - nothing, decided to take off the top vacuum line to N75 and go for a super quick spin - absolutely nothing even the 3 psi was gone. I had thought removing the top line wouldn't trigger wg to open and allow unlimited boost? Anyway, with that not being the problem I hooked the vacuum line up again and went for a boot and all the boost was back (dont have a gauge :( yet)

Car is a 98tqm, chip, bov, downpipe

Any idea what is going on or if my understanding of the n75 valve function is incorrect?

Avantium
10-05-2011, 06:25 AM
Drove the car this morning to work, boost gone again. thinking it might be LIMP mode? Should pulling the codes be the next step? CEL is not on.

Dusty Mauve
10-05-2011, 06:30 AM
Had a somewhat similar problem once, I could hear the turbo blowing, but the car drove like shit. Turned out to be a leak in the pressurehose from turbo to frontplate. Worth a look atleast ;)

MIDNITEAUDI
10-09-2011, 03:07 PM
get a boost gauge. you can test the resistance on the N75 to see if it is still good. yes, disconnecting the N75 should keep the WG closed = max boost. interesting, keep us posted if there are any other symptoms.