Car: 2004 Forester XT 5MT Mods: VF39, STI ecu, STI intercooler, APS short intake and filter, 3" turboback, stage 2 nuke tune, grimmspeed 3 port BCS Miles: 123k Description: Warmed up car this morning, when I got on it a little to merge boost went up to around .6 (factory gauge) and then felt like it flattened off completely and even lost a little power. Sounded like the wastegate was fluttering a lot. Stayed off it until my exit, then was on it a little bit after a light (not WOT), same thing happened, this time check engine light flashed 5 or 6 times, then went off. Have not yet had a chance to pull the code. Recent maintenance or modifications: None Anything jump out that I should check / look for when I get home (in addition to grabbing the code)? Thanks for any insight.
Check to make sure the waste gate arm has not lost its circlip. If the arm disconnects the gate will be flapping freely. This happened to me a while back, on the first really cold day of the year as well.
Awesome, thanks for the suggestion - that is exactly the type of simple thing I was looking for help on - especially considering the weather.
If that circlip falls off you typically don't see any boost. You loose it all through the wastegate flapper. .6 on the factory gauge is about 8.5psi or wastegate pressure. Take Nuke up on the log.
I had the same thing happen to my first FXT the winter following my VF39 turbo install. You will need your turbo's wastegate ported.
Serious?!?! Well then it can't be that the turbo needs porting. I remember doing the 3/16" mod to the VF39's airline. Not sure if that's the culprit but worth a check to see if its clogged. Also, I didn't do the GM Solenoid that other XTis did. Feelin' too lazy to do a search to find out if its true or not. Decided I'll just go off of memory.
Update: After the temps warmed up, the cold weather creep was a non issue, so Nuke reflashed to the previous tune, still had the problem, so we did some logging and found misfire in cylinder 1. Swapped the injector, no change. Borrowed a coil pack from my other FXT and swapped and the issue was gone. Installed a new one this past weekend and its running great again. Thanks Nuke for all the help!
