Can't boost below 19 lbs (with mbc)

[RawrImAMonster]

So I finally got a boost gauge for my car to see what the previous owner had the boost set at. I went for a full throttle second gear run and it got up to around 19 psi. Luckily this was pretty much the first time i've ever been at WOT, so I doubt the engine has taken much damage from it.

Anyways, after seeing this I screwed the mbc almost all the way out. No effect at all. I have no idea what type of boost controller it is or anything as it has no markings and I haven't been able to find a picture of one that looks like it.

Another thing, I'm pretty sure that the turbo on the car is a ebay 16g. I think I've read that these turbos need to have the wastegate adjusted. Maybe its set too high and I can't boost below 19 lbs? If so, how would I go about adjusting the wastegate, I tried searching, but didn't find good instructions for adjusting it.

So, what do you all think? Is something wrong with the mbc or the wastegate?

 

[imagine3163]

So I finally got a boost gauge for my car to see what the previous owner had the boost set at. I went for a full throttle second gear run and it got up to around 19 psi. Luckily this was pretty much the first time i've ever been at WOT, so I doubt the engine has taken much damage from it.

Anyways, after seeing this I screwed the mbc almost all the way out. No effect at all. I have no idea what type of boost controller it is or anything as it has no markings and I haven't been able to find a picture of one that looks like it.

Another thing, I'm pretty sure that the turbo on the car is a ebay 16g. I think I've read that these turbos need to have the wastegate adjusted. Maybe its set too high and I can't boost below 19 lbs? If so, how would I go about adjusting the wastegate, I tried searching, but didn't find good instructions for adjusting it.

So, what do you all think? Is something wrong with the mbc or the wastegate?

Did you try disconnecting the mbc and seeing how many pounds you run off the wastegate?

 

[RawrImAMonster]

No, where should i reattach the vacuum lines once I take them off?

 

[ummdsmwhat]

do you still have the stock mbc mounted? its underneth the intake. if so: connect a vac line from the turbo housing nipple to the top nipple on the stock mbc. then connect a vac line from the bottom nipple on the stock mbc to the wastegate nipple....if not: connect a vac line from the turbo housing nipple to the wastegate nipple....after this is complete - take it out for a few runs and see where your boost is hitting. that will tell you when your wastegate is opening at. if its a ebay turbo get ready to replace that thing....ebay turbos are know to only last on average 500miles....i know like i said "on average". i dont care that your buddies has lasted like 5k miles....ok ok anyways let me know if you need further guidance....

 

[RawrImAMonster]

Oh its already mostly blown. It smokes sometimes and has loads of shaft play. I didn't put it on there, it came with the car. I was just asking if you all thought it was the wastegate because if so I would just wait untill I got used 14b to replace it for now.

 

[imagine3163]

No, where should i reattach the vacuum lines once I take them off?

All you have to do is attach a line from your pressure source to the wastegate actuator.

 

[RawrImAMonster]

Ok, I just hooked up the wastegate to the vacuum line where the MBC was hooked up (the bov line). I know this is the wrong place, but it should still work alright for this.

Anyways, with the vacuum line going straight from the bov line to the wastegate, the boost was still too high. So, the wastegate either needs to be adjusted or I need to just wait till I get a 14b. If its easy to adjust I don't mind doing it, I just haven't found a good set of instructions for doing so. What are you supposed to adjust and which way does what?

Thanks for the help so far.

 

[DRAGIN]

Yea sounds like MBC is F'ed.

 

[RawrImAMonster]

I don't really see how the mbc could be screwed up. The ball and spring are still there. I mean its not exactly the most complicated piece of equipment . And since the car boosted 18 lbs coming off the waste gate, I think that it is adjusted wrong rather than there being a problem with the mbc.

 

[gofer]

heres the deal...
are you spiking at 19psi or holding 19psi through redline? if your holding 19psi through redline your wga needs adjusted http://www.dsmtuners.com/forums/newbie-forum/274251-video-how-test-wastegate-actuator-wastegate-functionality.html#post151315485 and theres a video on how to adjust it...

if your spiking at 19psi and then it settles to a lower psi its because the way your vacuum lines are hooked up... http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/237982-best-way-install-mbc.html#post50468083

good luck

 

[RawrImAMonster]

I'm pretty sure its holding there, but I let off really fast once I saw how high it was getting. At half throttle it will hold at 15 psi, so i'm guessing its the wastegate that needs to be adjusted.

 

[ummdsmwhat]

^ yea. do you have an external wastegate or is it internal? it is a ebay turbo like you said so that means that the wastegate could be unknown to when it opens....seriously just hook up a vac line from the turbo housing nipple to the wastegate nipple and thatll show when it is opening. just get that nasty turbo out of there

 

[ummdsmwhat]

^ yea. do you have an external wastegate or is it internal? it is a ebay turbo like you said so that means that the wastegate could be unknown to when it opens....seriously just hook up a vac line from the turbo housing nipple to the wastegate nipple and thatll show when it is opening. just get that nasty turbo out of there

 

[el guapo]

i hooked mine up backwards once by mistake and it spiked like that

 

[DRAGIN]

I don't really see how the mbc could be screwed up. The ball and spring are still there. I mean its not exactly the most complicated piece of equipment . And since the car boosted 18 lbs coming off the waste gate, I think that it is adjusted wrong rather than there being a problem with the mbc.

I've seen it happen and I know they are not that complex. The bottom line is, hook your wastegate directly to a vacuum source. Generally the input side of your factory boost solenoid is the best one. You can also T into your vacuum hose going to your BOV. You want it to be taken somewhere between the compressor outlet and the throttle plate. One a 1G it's a nipple on the throttle body with a P on it for Pressure. Do that and see what you get. IF it hits 19psi it's an actuator out of adjustement, internally failed actuator, or sticking/lazy wastegate flapper door. If not it's your boost controller. Bottom line.

 

[RawrImAMonster]

I already said that I've already done that and it was STILL 19 lbs. I'm positive its the wastegate, i just need to know how to properly adjust it.

 

[RawrImAMonster]

Never mind, I figured it out, it was the wastegate having been adjusted wrong. All you do to turn down the boost is turn the rod counterclockwise a few times and set the locking nut and youre good to go.