Need help identifing a weird noise
 

As I am driving my car is making a weird sound, kind of sounds like the word yelp, but very high pitched. It seems to only be happening when I am accelerating "slow or fast". If I am in neutral or pressing in the clutch the sound goes away...I tried to search but I cannot find anything regarding this sound. It seems to be coming from the back of the block/drivers side area. Sorry for the crappy description, but thats all I can think of. Please help me out, and if you have any questions to help diagnose the situation please let me know.

Bad throwout bearing?

That is what me and my dad thought, is there a way I can narrow it down? Such as if it occurs while I am decelerating by using the gears not brakes ?

When it's the throughout bearing, it will make a noise with the clutch out, and it goes away with the clutch in. If you apply pressure to the clutch pedal, but don't actually disenguage the clutch, and the noise stops, then that's the throughout bearing.

Some sounds are hard to diagnose by description, so a sound clip would help a lot if possible.

Found out that the noise is coming from the back of the turbo/downpipe...
The wastegate being opened or closed (manually pulling the wastegate) changed the pitch of the noise. It sounds like the turbine is hitting the housing... would that make sense that the pitch would change due to the wastegate status? I placed a screwdriver on the turbo and determined that the sound is coming from the back (shock to screwdriver was much more fierce in the back". Any suggestions are welcome. Thank you.

Yeah, the turbine housing sounds like a kazoo when it's hitting the housing. This video is a great example. Thanks Scott for the video.

Go to gpopshop.com and buy a rebuild kit for your turbo. Then go into the forum archives on the main page and follow the T25 and T3 rebuild how-tos and do it yourself. Just remember, the nut on the compressor wheel is most likely reverse thread, you can tell by looking at the threads.

Could it be possible that I did not tighten the four bolts enough? I do not have a lot of shaft play on the compressor side, but I believe the turbine housing may not be pulled as close to the center as possible. I am @ work so I cannot see if what I am thinking is true, just wondering if there is validity to that situation and making the noise.

Ryan, is this happening on the new turbo you just picked up?

yep, I disconnected the drain line and ran it for approximately 30 seconds and no oil came out. The feed line is bad somehow, after work today I plan to take off the Tee and see what is blocking it. Damn NB and its fake pressure gauge. I think that is the issue, hopefully nothing fried in the turbo because it was never really pushed or driven for more than 3 minutes... I felt the tee yesterday and I felt some oil, could it be that the tee is just not tight enought and maybe got a metal shaving blocking it from the tap process? I plan to drain the oil, take off the tee and feed line, clean them and start it back up...any suggestions? Am I correct to believe that my oil pump is still good due to the fact that I felt new oil on the tee/feed line connection?

It's possible, they would have to be aweful loose though. Turbo's have very tight clearances, if the housing isn't bolted perfect that could be the problem.

If your oil pump wasn't good your dummy guage would show it. When OP drops below like 10-15 psi, (not sure), the gauge will show a pressure drop. You can conver that gauge of yours so it show's real readings if you want. There is a couple writeups on miata.net.
What i did was prime my turbo with oil by hand, they only need a couple drops at idle so put some in by hand and disconnect the feed. Put it in a large cup or whatever you have and figure out why it's not squirting oil. Could be blocked, hard to say though from over here.

so there was no oil in the feed line? or no oil in the turbo?

If the feed line has oil it could be that the inlet feed on the turbo is blocked somehow.

Other than the oil, did u get it all together now Ryan?

Thanks, I have seen the articles on m.net, but haven't got around to it yet. Glad to know its not a dead oil pump :bowdown: I think what happened was when I felt oil on the tee I screwed in the fitting a couple of turns "4 revolutions" I think the line probably got kinked...I should be able to see it today. I think my weird noise is attributed to the lack of oil as well seeing that it is right in the CHRA/turbine housing.:) Thanks for all the help...

Adam, there is no oil in the feed & or turbo... I think it is blocked @ the tee...

Feed line was indeed kinked...I pulled the line, unkinked it, now the car runs...horray.