Boost leak?

[V-DUBchic]

Hey guys, looking for some advice. i've got an AWP with FMIC, 3" TB, TIP, CAI, DV, DIY'ed catch can, secondary air deleted, and chipped with C2 Motorsports. When i was first chipped, it was great! At WOT I spiked at 22 and held around 17-18psi. But after adding a couple mods (maybe it was the catch can? or the splitter dv?) and lots of mileage, ive noticed that now at WOT I spike MAYBE at 18-19 and hold at 14-15psi. The car doesnt feel like its got that pep it had when first chipped. Another fact to keep in mind is before it was chipped, the car pulled 195hp at the wheels. NOW, after being chipped for several months with alot of mileage, it dynos at 193hp at the wheels. WTF?!? i'm assuming i have a boost leak? or should i be concerned about any component about to fail? Thanks!

[jon-vw]

My setup is similar, a few things you can check that I've experienced:
-Ensure the bolts on your wastegate actuator rod haven't backed off (common problem)
-Test diverter valve + check for slightly torn hoses in the vacuum system (I've had a forge 007p with a bad rubber seal in the past, would bleed off boost, but was still able to hold pressure)
-Turbo to manifold gasket could be going (This caused lag and loss of boost for me in the past)
-Replace MAF (this worked for me, I had no leaks at all and regained 4 psi from a new MAF)

Those are good places to start. Pop off a charge pipe close to your front mount and see if there's any oil clogged in there. (unlikely, but you never know)

[V-DUBchic]

thanks! i swapped my DV with another known good one and no luck. but i'll use this as my check list.

[jon-vw]

No problem. Again, since you are still able to hold some amount of boost it doesn't always point to a boost leak. If your max boost gets lower and lower I would definately pressure test the system if you can get ahold of one.

Also check your backpressure if you have a vacuum gauge, a clogged cat could also do that if I'm not mistaken.

[V-DUBchic]

looked at the wastegate. nothing seemed to be loose or out of place. i did notice a hose under the manifold wasnt securely connected, but it was coming off a check valve near the oil filter housing. that did nothing i also noticed that my boost is getting slightly lower. it now spikes at about 16-17 and holds at 12-13psi .

[V-DUBchic]

i think i'll swap out the N75 for a known good one and maybe even the MAF.

[dubinsincuwereindiapers]

build a boost leak detector, it's in the FAQ thread and such.

also do some little stuff cleaning, like hte throttle body, run some 44k, and of course, make sure all connections are tight and squeeze test all vacuum lines. they look ok but can still be junk.

This.. x10000000

[V-DUBchic]

ok, so i swapped the MAF and N75 with a known good car and no luck. Part numbers matched right up with the donor car too. I keep looking at all my hoses and see no physical defects. what is this 44k stuff? i'm assuming fuel injector cleaner? if so, i ran some pretty potent stuff called 4-power about 2 months back. the throttle body should be clean, because when i took off the intake manifold to paint it, i cleaned the hell out of the TB. that was about a year ago. Maybe a small exhaust leak? I cant hear on at all! I was planning on upgrading the ko3s to a ko4-001. I guess it's time now! maybe swapping the wastegate, changing the gaskets, etc will fix the problem!

[V-DUBchic]

i'll also, check out this DIY for the detector. thanks everyone for your advise

[lowblackdub]

Having the same problem. Did you resolve yours?

[matty675]

There is no substitute for a pressure test. PERIOD.

Progressively pressurize the system up to your spike level and listen for leaks. They will manifest themselves as a loud hissing or whining sound. You will find several, undoubtedly.

I thought my system was solid until I pressurized it to 20 psi and found 3 boost leaks and one vacuum leak.