i need help guys, today i installed a test pipe, downpipe, o2 housing, exhaust manifold, hallman MBC.
after everything was installed me and a bud took it out for a test drive, everything was fine but my boost gauge was reading 10-11 psi. referring to the DIY thread it was either not on right or it was at stock boost, so we checked the lines and turned it 2 full turns. boost was still the same, turned it another 2 1/2 turns and it boosted to 15psi but i heard a pretty distinctive THUMP when i got to wot. we pulled over checked everything, everything seemed to still be connected turned the boost completely back counter clockwise and drove it home. but if i try to boost alittle it would boggle and want to die, usually around 3k rpm

we checked all the lines again and they seem to still be all there, i capped off the turbo waste gate actuator and intake, and routed the lines from the mbc to the waste gate and turbo

 

you're probably going to need a tune, also make sure you don't have a large exhaust leak somewhere. Did you remove/replace the stock lines, it has a boost pill in it?

 

which stock lines, i know i would need a tune but the thing is my car isnt even boosting any more. it did until i wot with 4 turns on the boost controller and the thump happened, im pretty positive that its not a exhaust leak cause it was driving fine until that happened.

 

your intercooler piping blew off. check that. then retune your MBC at about 21-22 psi then get a tune. your car wont blow up right away it's ok

 

No intercooler pipes were blown off, and i checked the bov and it is also fine.

It only happens when i put a load on it and just as the boost pressure is about to build up, no boost.

I dont think it has to deal with any of the exhaust upgrades i did either, but i dont know much about the stock wastegate. Could it be stuck open, and if it is, what are the symptoms?

 

I promise you, you have a boost leak somewhere. intercooler pipe blew off. what intercooler pipes did you pull off to do the exhuast work?

 

i've blown off intercooler pipes before and this is no where near it

 

Then I guess I have no idea as to why a car would "Thump" then bog under boost. It SHOULDN'T have anything to do with your wastegate though

 

sounds coupler was blown off, but also make sure you have the MBC on correctly, I"ve seen them put on backwards.

 

The Thump happened when i put into wot and it felt like fuel cut. Afterwards i couldnt build any boost pressure. it would go from 16vac to 0psi and then again no boost.

The car idles and drives fine when not boosting (which also indicates that intercooler pipes did not come off) but any signs of boost trying to build, the car BOGS and no boost.

The rpm still goes up as normal and car still accelerate fine, just until it builds boost anyways.

The question remains, what is keeping me from boosting??

wastegate??

help...

 

okay, first, did u reuse the stock boost line? second, the Hallman MBC come with an extra spring which is the hard one, did u put that in? it's most likely ur BC.

 

Make sure the MAF is plugged in. Did you hook up the mbc like this?

 

No, I didn't hook it up that way. I capped the turbo wastegate actuator and intake, went from the bottom of the mbc to the turbo and the side to the waste gate actuator. I also swapped out both springs and same results. I screwed the mbc counter clockwise all the way (was told to start at low psi and up until I find setting i wanted). And no I did not use stock boost lines, I used the one that came in the MBC and a extra longer one I had from installing the boost gauge.

 

keep turning your Mbc clockwise it takes a lot of turns before it goes up.
Y hallman Mbc took 24 turns before it reached 21psi of boost

 

I was getting normal boost until the thump, now I can't get boost even if I turn the living hell out of it. According to my boost gauge everytime I am close to passing 0 the car bogs and doesn't allow me to accelerate any further.