I have an 09 LNF with;

ZZP Uppercharge Pipe
ZZP Short Ram Intake
ZZP Catless Downpipe
ZZP ZFR 6758
HAHN Intercooler
GMS1 3 Bar Map Sensors

Tuned with HPTuners.

I'm running a 25psi tune that was working perfectly. Last week I changed my clutch out and put the GMPP LSJ Kit in with a new LSJ Flywheel. Now, for some unknown reason that makes absolutely no sense to me, I'm not boosting properly. I normally hit 25-27psi at WOT but now, I hit 15 from 3krpm-5krpm, after 5krpm it climbs from 15-25 as the rpms go through 5k-6.8k. I disconnected the ECM, the entire Underhood Fuse Block, Back Up Lamp Sensor, 2nd O2 sensor connector on the DP and everything else was suspension, cradle and the trans itself. We checked the tune and it's still commanding what it's supposed to but I can't boost worth a damn and can't seem to figure out why.

No DTC's and according to the Tech 2 at work, and HPTuners, my car is running like it should, so I have nothing to go on at the moment. I double checked all of my connections, hoses, fuses, ecm connectors, everything. I'm at a loss.

 

Map sensors?
Were they spliced in or did you use the ced connector

 

They were spliced in when I bought it, but they lost connection randomly. I soldered and heat shrunk the connections at 35k miles and haven't had a problem since.

 

Could it be phantom knock due to a loose or misaligned flywheel? Are youpulling timing because of knock?

 

Maybe the boost control solenoid is taking a crap. Seems odd that the car would boost ramp itself lol.

 

There is no knock at all during WOT. 13.5 degrees of timing up top. The car runs like a champ other than the boost issue.

 

Smoke tested directly into the intake and into the intake manifold today. No leaks anywhere.
Readjusted the Wastegate Actuator as well.

Same thing. I did notice I have a weird rumble that sounds like it's coming from the exhaust when I rev to 3500rpm as the revs come back down. It rumbles for a split second then disappears. Maybe the resonator?

 

 

I want to say someone else on here had a similar problem, but I can't remember who it was.

 

Ran another boost leak test just to be sure and came up with nothing. Seems like no one on the planet has any idea what's going on.

I'm going to disregard the clutch installation and say it's a coincidence. It's like the turbo can't spool fully until 5krpm.

 

Map sensors/ wires
Maf/ wires
Waste gate/bpv
Vacuum leak
Thats all I got

 

I ran a smoke test and there's no vacuum/boost leaks. Checked both Map Sensors and they're fine as well. Only thing I haven't tested is the W/G and the Solenoid on the Turbo. The MAF is reading correctly too.

 

https://www.cobaltss.net/forums/show...631&styleid=10
Finally found it
Yeah I would start looking at the wg rod and the actuator solenoid