No power in 2nd gear and up... boost creep then fuel cut.

[Fayt]

Alright.. I'm not sure if it could JUST be this problem, but I'm pretty sure that it is. I just put on an Evo 3gt w/a 3" exhaust no cat. However, I'm hitting EXTREME boost creep in 2nd gear and up. It'll spool up and build pressure, but then it'll eventually misfire a little, then hit fuel cut and buck/stop, and I hear air coming out of somewhere like "PSSSSHHHH" once boost hits. Dunno if the wastegate is opening prematurely or something.

It's really bothering me, because I have almost NO power from 2800 and up. I can't go over 80 because if I tap the gas I hear the PSSSH sound and it'll backfire/cut. I'm still running stock boost from the solenoid too. Some things I've found when searching is that I should...

-Install a MBC to regulate the boost better and
-Port my o2 housing. It's a stock o2 housing on an Evo 3g w/a ported exhaust manifold. 3" exhaust w/no cat from o2 back.

Is there anything else it could be? I do have a minor exhaust leak from the o2 to the downpipe because of the size difference that should be fixed soon. But, seeing if there is anything else to check.

 

[bojanglesracing]

Have you done a boost leak test?

 

[Fayt]

Yes, there is a tiny boost leak.... not sure where it is though. I tested from the turbo inlet and heard it up near the intake manifold, but I've check EVERY vacuum line. I c-clamped every line nice and tight, tightened down all clamps around the intercooler lines, replaced my throttle body screw (it was a bad o-ring), all EGR lines at the bottom of the manifold, my MDP sensor was bad, and all the solenoids on the firewall. I have one TINY one that I can't pinpoint, and I think it was from my boost tester anyways. So, I'm gonna try testing from the LICP and the tighten the J-Pipe down more.

Would one small boost leak do all that though?

 

[Jeremoose]

Yes, there is a tiny boost leak.... not sure where it is though. I tested from the turbo inlet and heard it up near the intake manifold, but I've check EVERY vacuum line. I c-clamped every line nice and tight, tightened down all clamps around the intercooler lines, replaced my throttle body screw (it was a bad o-ring), all EGR lines at the bottom of the manifold, my MDP sensor was bad, and all the solenoids on the firewall. I have one TINY one that I can't pinpoint, and I think it was from my boost tester anyways. So, I'm gonna try testing from the LICP and the tighten the J-Pipe down more.

Would one small boost leak do all that though?

It did it for me, possible for you too I was on the stock T25 though.

 

[Fayt]

Well, I have 3 more leaks to fix, one I fixed and I think thats it...

-My PVC is leaking a GOOD amount, ordering a new one Monday.
-The TB elbow gasket is leaking a tiny bit on top, I'll order one of those too.
-The TB seals are leaking... the ones where it leaks and you can turn the arm to change the airflow/leak. I'll fix that once my seals come in. I just ordered the ones from Mach V because I KNOW they work and I don't want to have to do this again.

- My UICP wasn't c-clamped down to the SMIC, just loose so I was probably loosing some boost there too. Clamped that down nice and tight, about to take it for a drive and see if it helps any/at all.

I'll fix those then see what happens.... Keep you updated.

 

[Fayt]

HOLY SHIT!!!! Big difference that made. It pulls HARD to redline. However, it'll backfire sometimes around 5-6k. Probably because of the 1st gen motor.

Wow... you have no idea how this feels. Almost one whole year of not driving my car... bought it and had it for 2 months. Time for some fun.... heheheheh.