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ActiveMonkey
12-04-2006, 08:32 AM
So I think this is the Wastegate, but I would like some opinions before I go buy one.

So I will be driving down the street in 2nd and go wot, it goes zoom and all is fine. However this morning I was being lazy and didn't want to downshift to pass this mini-van so I floored it in 3rd. I hear the turbo spool, and it reached full boost but it was Pulsing as it tried to hold the boost. WTF!? I waited, shifted into 4th and again went wot. Turbo spools then I hear the exhaust pulse although the wastegate was not holding boost.

So what do you guys think?

sandnessmj
12-04-2006, 09:27 AM
I think I'm getting this same thing. WOT in 4th and 5th after about 4k rpm and I hear pfft-fft-fft-fft-fft...it pulses quickly, say 3-5 times per second...

bitterchild
12-04-2006, 10:19 AM
that's the wastegate operating... 3-5 cycles a second is a bit less frequent than an n75 should be

mike-2ptzero
12-04-2006, 10:41 AM
Could also be the BPV not staying shut, when this happens you will see boost but the amount of air flow will be decreased since the air is being cycled back to the front of the turbo.

sandnessmj
12-04-2006, 12:00 PM
Thanks guys, at least I have a few places to start.

I had this nightmare last night that the turbo or manifold wasn't torqued down correctly and a gasket was blown out and was fluttering and emitting hot exhaust gasses underneath the hood...[eek]

offroader1006
12-04-2006, 12:10 PM
boost pulse is usually result of the control valve.

when its that noticable it probably needs to be replaced.

sandnessmj
12-04-2006, 12:14 PM
Yeah, I'll start with cleaning out the DV and making sure that functions properly, and then if that doesn't work I'll replace the N75...

ActiveMonkey
12-04-2006, 02:56 PM
I have a new TT DV that i'll throw on there and see if it helps. Hope it's not the EVOMS DV

Nor1824
12-04-2006, 08:16 PM
I am having a similar problem. At WOT my car gets up to 14.7 but cant hold it. It get the pft...pft...pft sound from my exhaust and the car pulses. To the best of my knowledge my forge DV is fine. I will have to double check.