Low Power

[-K-]

I have been feeling underpowered for a month or so. I built a catless DP and was dissapointed that the turbo didn't spool any faster (though I can get more than 9psi now) I ran it at the track on 12psi and 16.2 was the fastest I ran. (15.9 was my best with the cats) Fuel I thought? I checked my codes and came up with O2 and VSS. I just installed a 255lph fuel pump and a temporary almost new one wire O2. Cleared the codes and they have stayed clear (didn't do anything to the VSS). It runs much smoother and feels better at high RPM. I ran it again and got a 16.3. Turned the boost down to 10psi and ran the same Today I installed a A/F gauge and it seemed fine on boost it goes to about the mid rich and stayes there. Off boost it sweeps all the way from lean to the first rich. So I decided to hook up the stock boost controller. Same thing, and about 9.5-10psi. So how much should it swing rich to lean crusing? Anything else I should check? It feels stong just not as much as it used to. I am going to check the plugs and compression and let you know how it goes.

[vrg3]

A narrowband air/fuel ratio gauge only gives vague indications as to the actual mixture... The size of the swing during closed loop operation will vary from car to car and with the type and condition of the oxygen sensor.

Could it be a clogged air filter? Or a small boost leak? Have you tried just resetting your ECU?

[-K-]

Thats about what I thought for the A/F. I have about 1k on a new K&N. I now what a boost leak feels like (stock BOV does that sometimes on part boost) and I checked all the turbo to IC to TB clamps. I gave all the little hoses a look also. I left the battery unpluged all night when I put in the O2.
I'm kind of at a loss....

[vrg3]

A boost leak is different from the blowoff valve leaking... a boost leak to atmosphere messes up the air/fuel mixture while a leaking recirculating valve like the stock BOV doesn't.

[-K-]

Ok, now I'm getting some pinging. I checked the fuel pressure and it's kind of funny... 32psi on idle, 39psi at no vac, but here is what I find stange. Under boost it jumps all over the place, 40-50psi as far as I can tell, it's all a blur. So it looks like I need a FPR. I'm going to change the fuel filter first but it only has 2-3k on it.

[vrg3]

Yeah, it does sound like the FPR's misbehaving.

You've checked the easy stuff, like making sure it has a good manifold pressure signal, right?

[-K-]

Yes, they are all connected and tight. I started it up this morning and it was running so strong. The fuel pressure didn't go up as far as it should (only 50psi at 10psi boost) but it didn't flutter at all and the A/F was higher in the rich. No pinging. So it looks like I'm going to get a FPR.