I am pretty sure this is a boost leak, but I thought I'd post anyway, because there are reasons why I am questioning this theory.

OK, so I start her up, and warm up of course... Runs fine under boost. Until about 30-40 min after crank, it acts like a boost leak (a big one). Upon spool up @ approximately 3400 rpms and throttle, it bucks and hesitates, resulting in me shifting to lower the rpms. Below ~3200 it spools great, and then just above 3000 flatline. The gauge reads, but it bounces a LOT (aftermarket gauge). Like between 4 and 7. Side note: I have blocked off the BAC, sec. air inj. system, the sub-zero start assist. I am preparing to get a bnr stage 3, as I need a nice ported waste gate. another question, will a 34mm wastegate (bnr s3) control boost better? Like nearing stock levels? I am not prepared to do the necessary fuel upgrades right now to run high boost (I will eventually get a rtek 2 and 720 secondaries. already running a walbro 255). Yes, my cats are hollowed, and yes I have new intake (not quite cai, but oh well, just want it to run better right now). It seemed to staret about 3 weeks ago. I have had to use the car for a DD, so I stay off boost at all times (better to anyway because the narrow "urethra" of a WG).

EDIT: when I say bucks, its not bucking, more like power loss, not due to fuel cut or so I theorize, because I get popping in the exhaust like fuel is running out the exhaust. Hmm, come to think of it, maybe it is fuel cut. Guess its time for an FCD to test this theory. Any ideas? I have never hit fuel cut at 3000 rpms... Guess the bouncing boost gauge says it all huh?

 

may sound stupid but check your secondary injector caps, my n/a had a simi similar prob and it was a loose fi cap

 

Unplug boost sensor...
Try it.
Does it still do it?

If not, you're hitting fuel-cut.


-Ted