Boost problems after FMIC

[TURB0]

Here's the deal: I just installed a full FMIC kit on my car, other mods listed in my profile. Well after the install my boost seemed to have change to about 11psi. However after a few pulls I noticed it acting very strange. In 1st and 2nd I boost to 11psi and fall to about 6psi, even with my MBC all the way open. However in higher gears my boost seems to steadily climb to redline. My initial thought was a boost leak, so I went back and retightened all of the clamps(I do no have my boost leak tester with me anymore). Yet I am still getting the same results. Does anyone have any input as to any other causes? Could maybe a clogged cat be causing it?

 

[maperformance]

So by all the way open do you mean a wide open path to the actuator? If so there is a serious issue. Otherwise we have noticed this in the lower gears as well, it is probably related to the actuator as it has less time to open/close and reach your target boost.

Chris

 

[TURB0]

By wide open I mean I was trying to extract maximum boost from the MBC. In other words, no matter how high I tried to crank it, it would give me the same amount of boost.

 

[talontd92tsi]

The best thing i can say is buy/make a boost leak tester, thats about the only way to find hard to see boost leaks.

Maybe check the weld on the bov flange, maybe it has failed.

 

[oldman]

No installation of any kind which involves the intake tract, especially in the case of FMIC, can be considered complete without a boost leak test.

 

[TURB0]

Yeah, boost leak was already on the top of my list. but my tester wasn't in my possession at the time. I was just asking if their was any other known causes for this.

An update as well: I tried to bypass my MBC and now my boost is acting different. Boost builds much faster and it holds firm at 10psi(stock boost?) I'm thinking now that it may be just a faulty MBC. Was it common for boost to fall in first gear only by a few psi on stock DSM's? All other gears seem to hold firm

 

[oldman]

It's normal to not hitting full boost in 1st due to less load but it's not normal to drop after hitting full boost.

After looking at your profile, I'm assuming that your BOV is vented, is your TurboXS MBC hooked to the BOV line?

 

[DSMcamaro]

Also check over all the lines going to your MBC. Check for leaks and pinches. I had a similar problem once and my custom CAI was was pinching off the line that went from the wastegate to the MBC.