update: it's at 12psi again, but still need some ideas, read last posts please.
 

ok so my turbo zc crx is having an issue. i just sold the car so i can't go check things out, but i figured i'd get some ideas from you guys anyway.

so a few weeks ago i was gonna post the car on craigslist. i turned the homemade mbc down all the way so no dumb ---- from craigslist blew up the car. a week later i decided to not post it there and i was gonna keep it. so i tightened up the mbc a little and went for a drive. wastegate opened at 5 psi. i pulled over and screwed the mbc tighter. still 5 psi...
so i figured my $3 homedepot mbc was crap after 6 months and it needed a new one.
i ended up selling the car and the guy that bought it put another homemade one on and it's still doing it. i told him to find someone with a mbc that he could borrow and let me know if that fixes it.
then i started thinking maybe the charge piping is leaking at 5 psi and it's not the wastegate opening. so i told him to check all the charge piping.

i just did a compression test and a leakdown test so i know the motor is good enough to build boost :l

fyi: the wastegate is a cdm one

any ideas of what might be going on if the mbc is fine and the charge pipes are fine? it drives fine, everything seems normal. bov sounds good, sounds like the waste gate is opening. car is not smoking anymore (replaced valve seals). all is good except for the 5 psi.

Re: boost controller not working. wastegate is opening at 5 psi.
 

maybe a bad diaphram

Re: boost controller not working. wastegate is opening at 5 psi.
 

i should also add that the wastegate is set for 5 psi

Re: boost controller not working. wastegate is opening at 5 psi.
 

change the spring in the mbc to a stronger one.

Re: boost controller not working. wastegate is opening at 5 psi.
 

yeah that is what i was thinking, but he said he made one also.
i told him to grab a "real" one from a friend and see if that fixes it.

Re: boost controller not working. wastegate is opening at 5 psi.
 

Pull the MBC off, remove the hose from the WG, and plug it - leave nothing connected to the WG. CAREFULLY bring the car into boost, and see if you can go above 5psi. Then try 10psi. Then...well don't get greedy, find a WORKING mbc. Problem solved. If not, then there's a bigass boost leak somewhere.

Re: boost controller not working. wastegate is opening at 5 psi.
 

What he said...

Re: boost controller not working. wastegate is opening at 5 psi.
 

if he does that won't it just boost to what the wg spring is set for? (5psi)

also he hasn't called since yesterday so i'm guessing he figured it out.

Re: boost controller not working. wastegate is opening at 5 psi.
 

Well, that's all it will see as long as it(the wastegate) has a vacuum line hooked to it....

Re: boost controller not working. wastegate is opening at 5 psi.
 

ok so if there is no line connected to the wg then it will see infinite boost right?