need help diagnosing turbo issue

[e34 life]

im looking for someone who can swing by and just take a look at my setup and help me figure out what the fu** with my boooooost!? im only building like 3 lbs of boost, ive checked for leaks in the charge pipes, and i just installed a new mbc?



thanks

-jeff

[SchwartzBR]

Are you in NOLA? I may be heading to the camp on Friday...could swing by and take a look.

[e34 life]

I'm in slidell, i work friday but I should be of by 8ish

[eseeling]

Can't swing by but... if you want to troubleshoot, then remove your intake and try spinning the compressor wheel - it should spin easily and not make any noise - also, try moving the center shaft - the play should be minimal and the impellers shouldn't touch the housing (You would hear it if they did).
If all of that checks, then it is probably a waste gate issue - I don't know if you are running internal or external. But, for internal, check the linkage and move it manually. In the fully closed position there should be a slight amount of play in the actuator shaft. For external, check the stroke of the shaft by applying low pressure air (crank the regulator down on an air compressor) or rig a small hand pump to watch the movement. External regulators will usually fail in the closed position, so the boost will go too high, but if the shaft seal is fouled it may be sticking open slightly.
That's my 2 cents....

[325isBoosted]

it says there can only be one boosted e34 around here haha. On a serious note, i think eseeling has the right idea, check the turbo and wastegate operation. How did you check for boost leaks, did you smoke it?

[e34 life]

wish I knew have of what your sayn! Forgot to mention im@sligtly a boost newb, I checked the charge pipes with soapy water On all the couplings and watched for bubbles

[hec325]

I wish I knew more about these turbos...I got nothing

[325isBoosted]

i would suggest finding a nearby shop that could smoke it, much easier to find leaks that way, external waste gate or internal wastegate on the turbo? Ill check and see if german has a smoke tester.

[e34 life]

external, I just wish some one who knew turbos could look at it. I've had so many people look and just scratch their heads

[325isBoosted]

did you try taking off the filter and checking for shaft play?

[e34 life]

not yet, will do when I get home from work, if I remember haha

[325isBoosted]

also double check the vacuum lines maybe you mixed somethin up when installing the mbc

[Bigmac834]

This only started happening when you installed the mbc?

[e34 life]

well I only have a 6 lbs spring... So I got my 1st mbc and got it up to ten, but then that broke some how and it's been at 3 since...so I bought my second mbc thinkn it would fix it but it didn't. And since I don't know what kind of wastegate the shop used I can't just replace the spring. I don't know how hard it is to identify a waste gate brand

[325isBoosted]

If you can take a picture of the wastegate, usually pretty distinct looking, what shop did the turbo? So before the mbc it always ran 10 psi? Id still lean towards vaccum lines or mbc.

[Bigmac834]

325isboosted: From his story he has a 6# spring in, it ran great at 6, then he added a mbc to up it to 10, that ran great for a while then it started only boosting to 3.

I would check for a boost leak. A mbc can't make the car boost lower than spring pressure.