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?

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

lol...I like the sound of that...but yeah, it'll climb until you let off the throttle or the engine pops, whichever comes first...

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

∞-(∞+(5^2))

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

ok so he called finally and said he bought a new mbc and it's still not boosting past 5psi.
i told him to unhook the wastegate. i don't think he understood me when i told him to watch the amount of boost. that it will keep rising till something stops it.
he said " so if it goes past 5psi where will it stop, so i know?" i said if it goes past 5 it's gonna keep going till a rod comes out the block..

Re: still need some ideas, read last post please.
 

ok he unhooked the wastegate and it opened around 5psi
i told him there is a leak somewhere and to also check the spring and diaphram in the wastegate. he said they are both fine.
now he wants to buy a different wastegate....

he says all the couplers are good and tight.
is there anything i should check? i'm probably going to his place today to take a look at it before he buys more stuff.
i'm going to retest everything listed so far, but what else should i look at?

Re: still need some ideas, read last post please.
 

does it idle funny if it does you might have a cavuum leak somewear like a throttle body gasket or something

Re: still need some ideas, read last post please.
 

no man it idles and runs great.
i thought it was just a broken mbc.
isn't it strange that a boost leak would be at the same psi everytime?

Re: still need some ideas, read last post please.
 

Not really, if you think about it. The charge pipes and couplers would hold to 5 psi, but any more pressure and there was a leak allowing air to escape. Makes sense...to me. :-\

Re: still need some ideas, read last post please.
 

Plugged catalytic converter is a possibility. Or perhaps a damaged turbine.

Re: still need some ideas, read last post please.
 

what kind of shape is the turbo in? If its a old haggerd one, I could see it not boosting past 5 psi. Im just thinking outloud. So im sot saying the turbo is bad, Im just saying it could be. Just like it could have a boost leak.

Re: still need some ideas, read last post please.
 

what is a catalytic convert :l
ok so i got it figured out. there was a boost leak, fixed that and it wouldn't go past 5 psi.
so i unhooked the wg and it went over 5 psi.
next i looked at the boost controller. he had some cdm one on there that he just bought so i'm pretty sure it's not broke.
i turned the adjustment knob the way the + arrow was pointing and it was still 5 psi. my wife said "maybe the ching chongs got the directions wrong" "turn the boost down all the way".
i did that and it went a little past 15psi. so i turned it back a few clicks and it was at 8psi. so it turned it back 1 click and it was at 10 psi. he wanted 12 psi so i went 1 more click.

sorry if that was confusing, it lost me when i was typing it.

so why the hell do i have the boost down almost all the way and it's at 12 psi. but if i turn the boost up it goes down.
do we have the hoses swapped.


right now we have them like this
Attachment 13518
the little "T" in the corner, where does that go?

Re: still need some ideas, read last post please.
 

could it be possible that the knob is wrong? it says clockwise will increase boost, but it lowers boost.
or do we have the hoses backwards?
the wg is set at 5psi, right now the mbc is maybe 2 clicks away from max boost and it's only at 12psi. shouldn't it be able to go higher then that? what if he wanted to run 20 psi?

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

It could be a bleed type mbc and the outlet line isnt supposed to go to anything, the "T" would go between the WG, the piping and the controller. Then the line coming out of the mbc would just vent, that would make sense for the "+/-", because + would allow more air to vent, stopping the top of the wg from seeing boost (as if a mbc wasnt connected). While "-" would block it off, causing more boost pressure to back up to the top of the wg, holding it closed.

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

so it would go like this?
http://www.racetep.com/dboost.gif

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

why can't i find better pics online anywhere?

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

---- it man if its running 12 then why ---- with it ???

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

Yes exactly, which type do you have?

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

well it's not mine. i just sold the car to a friend and i'm trying to get it perfect for him.
he had a boost leak, he thought it was the boost controller so he bought a new cdm one. the homemade one i built was fine, but now it's got a cdm one on it.
this is a pic of the one he has,
do i have it right in this pic?
Attachment 13513

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

I had a friend with that same boost controller, and we had to turn the knob backwards as well. I think the chinese just fucked up in production, and since they probably dont test their products, theyve never fixed it. I wouldnt worry about it personally. It works. If he wants on where the arrows are facing the correct way, tell him to not buy CDM products.

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

so did you guys leave the T unhooked?