No boost...Where do I start?

[4G63dsm1]

I've been having some boost problems with my car. It all started when I was coming out of work driving back home, I went to pass a slow car and stepped on it...the car felt like if it was bogging/Holding back. I Stepped it again at wot just to see if it was me and the car was not boosting, the boost gauge reads 5 psi (It's normally set at 15lbs.) If you hold the throttle long enough it has the same feel as if it was fuel cut. Anyone knows what can I check or start checking? When i'm not boosting car feels normal and drives fine. The turbo is not smoking and the Psssshhh sound from the Bov sounds extremely low, I can barely hear it. I got a 14B and a knock off greddy bov which I already change to a 1g bov, walbro 255 fuel pump (Not re-wired), Fuel pressure regulator set at 42 psi and 450cc injectors. I already check for boost leaks and there aren't any...Changed the knock sensor and fuel filter. Sorry for the long post.

 

[BLINKY619]

have you checked your couplers? it might of poped one... also to make sure you should perform a boost leak test....!!!! it also wouldnt be bad to check the turbo to see it its spinning freely and if it has shaft play....!!!!! it should be a good place to start...!!!!

 

[4G63dsm1]

have you checked your couplers? it might of poped one... also to make sure you should perform a boost leak test....!!!! it also wouldnt be bad to check the turbo to see it its spinning freely and if it has shaft play....!!!!! it should be a good place to start...!!!!

I already checked all the couplers, and also the turbo for play and it's all good...sorry forgot to mention that. Boost leak test will be this weekend.

 

[2gdsm_nc]

cat gutted? clogged cat, oh wait exhaust gasket blown, turbine to manifold gasket bad. wastegate diaphragm faulty. big azz gaping crack on wastegate flapper

 

[hurricanecris24]

check your exhaust manifold for cracks

 

[DSM Boosted]

Def do a leak test, and it's possible one of those gaskets like stated above are bad...I had almost the same problem, mine of course turned out to be a blown turbo though....

 

[nfernotalon]

Make sure the wastegate actuator is not holding open the flapper a bit maybe its caught on something. Check the blowoff valve see if it moved freely too.

 

[Aproductions]

Make sure the wastegate actuator is not holding open the flapper a bit maybe its caught on something. Check the blowoff valve see if it moved freely too.

+1 on that!

 

[zachsEVO3]

- And fast! I'm having the saaame problem with my 16G now. It sat for a year, ripped goin out the mechanics parking lot and now it doesnt boost past 0-5ish.

I wouldnt have thought any of the silicone couplers or gaskets could let that much air escape....even an exhaust crack can do that??

I'm checking the actuator/solenoid on the turbo how do i know which way is open/close? I dunno what else it could be.

 

[LiquidX]

You would be amazed at what a small crack say in a vacuum line or an injector insulator will do. When I still had a MAF setup, I blew off a vacuum cap on a nipple I installed on the intake manifold. Before I realized the problem, the car would stall out and drive like crap because of all of that air leaking out and getting sucked in. Boost leak testing struggled to get to 5psi and it would leak out instantaneously.

Exhaust crack would be the worst out of the two choices as the exhaust is exiting the system before it reaches the turbine to allow more air to be compressed and turned into exhaust. Consider it like having your wastegate taken off depending on how bad the exhaust leak is.

Do your boost leak test when you get your tester and fix all of your leaks. Don't forget to use a spray bottle of soapy water so you can look for bubbles to help narrow down your problem areas. Not all leaks will make noise either.