Turbo Problems...Screeching, Hesitation, Bogging...

[Spartekus]

Hey everyone, I am new to this forum but I have a good chunk of mechanical knowledge from DIY experience but I don't know what to do about this dang turbo problem. The turbo screeches between 4000-6000 RPM's very loudly like a metal on metal sound and is most prominent when the car is hot during the day ( I live in AZ ). I had the whole turbo assembly replaced two weeks ago because i took it in because of this screeching and they told me the turbo had internally failed. Well i got it on the road as i was leaving the dealership, i drove pretty lightly all the way home and then pushed it in the last two miles and heard the same screeching noise. I took it back to the dealership the next week and the lead mechanic rode with me, listened to this noise and said it was a normal turbo boosting noise. I said i didn't agree because I had just brought the car in for the same noise and they diagnosed it as a FAILED turbo. How does that make sense. This is the third turbo on the car in 35,000 miles and the last turbo only made it around 11,000 miles. SO there is definitely a problem! It has also had 3 catalytic converters in 35,000, so I'm not sure if something is wrong with some type of backpressure coming from the exhaust system. I notice that on a cool night the turbo doesn't screech as bad or at all, but during a hot day, its ridiculously loud! I need some help and I have read almost all of the threads that relate to this turbo issue, but i have yet to see any follow ups on how to fix the problem without modding the vehicle. I am strapped for cash right now also! I will also mention that when the turbo is screeching, i notice a drop in power under acceleration like the car is bogging down. That combined with the hesitation is enough to drive me crazy! Thanks for any help!

NOTE: The car is completely stock and has 35,000 miles...I bought it about two months ago and have not driven it hard at all...

 

[SleepyMSP]

I get the same thing on my car when I push 4500 RPM's or so, it sounds like the turbo is going nuts. I originally thought it was normal but started thinking there is something not too right about it.

sooo....bump for some info here

 

[Knox Joe]

I had the same thing. It would start screeching once the car was warm, and mostly in the summer.
Mazda had it for weeks. they swapped in a new turbo, and it still did it. I had to take the mechanic with me to demonstrate the sound still here, and he told me to leave it there.

While they had it they changed the exhaust to the updated Mazadspeed version, because they said it was something with the mid pipe, and called be told me it still did it, and that it wasn't going to go away.

After that I figured I was screwed on the warranty, I had gotten a brand new turbo, so I started modding.

When I changed the exhaust the screech went away.

 

[FLAMSP]

Stock as well, Mazda said it was normal.

 

[SleepyMSP]

When I changed the exhaust the screech went away.

I guess that would mean the screech isn't coming from the compressor then, maybe a its just the bad S-Pipe?

when you say changed the exhaust what did you change? CB or TB?

 

[Knox Joe]

I guess that would mean the screech isn't coming from the compressor then, maybe a its just the bad S-Pipe?

when you say changed the exhaust what did you change? CB or TB?

Perrin exhaust. J-pipe back.

 

[fr0st]

i got a somewhat "WEEEEEEEEEEEE" around 4500-6000 at times.. and again it depends on how much your flooring it / throttle position and temperature..

my guess was the wastegate not fully closed/open making turbulence in the downpipe... gonna be installing my catless pipe soon, maybe the sound wqill go away..

i dont know but it doesn't seem to be the turbocharger.

 

[SleepyMSP]

Perrin exhaust. J-pipe back.

Hrrrmm...might be the cats having trouble keeping up with the higher/hotter volume air coming out of the motor.

Just guessing at this point, if the cats getting dropped fixed the screech its a starting point.

Does anyone else with an aftermarket exhaust with hi-flow/catless have the screech??

 

[B1GHAM]

I have the same noise and have narrowed it down to the wastegate. I also spoke with a friend of mine (An awesome Mechanic who works @ Mazda) who agreed with me.

I havnet had time, but sometime soon Im going to replace the WGA (issues other than screeching), the only thing I can do is update you when I do.

If you want to try it yourself, its only a $70 part through ATP.

 

[Knox Joe]

See they specifically told me it was NOT the wastegate.

Hmmmm....

I'm not saying that's not your issue, but it definately wasn't mine because they swapped out the turbo and everything for me.

I read a thread, back when I was having this problem, about someone changing the exhaust and getting rid of the noise as well FWIW.

 

[B1GHAM]

See they specifically told me it was NOT the wastegate.

Hmmmm....

I'm not saying that's not your issue, but it definately wasn't mine because they swapped out the turbo and everything for me.

I read a thread, back when I was having this problem, about someone changing the exhaust and getting rid of the noise as well FWIW.

I ran open exhaust for a while, all that did was drown it out. I just dont see where the exhaust would cause the issue.

Theres also other weird whistling that tends to come from the wastegate (when bad) that the mechanics can never track. I would agree its a failing turbo - if it wasnt for the fact that no other "normal" failing turbo issue is seen in conjunction (varied boost, oil burning, leaks, etc).

I dont know... Like I said I havent actually replaced mine yet so I cant say with 100% certainty. I will try to do some searches, I remember reading similiar issues that were also suggesting WGA as the issue.

 

[Knox Joe]

Well like I said they replaced the turbo, and wastegate on mine, and it still made the same noise.

I doubt it would be bad brand new.

 

[SleepyMSP]

I ran open exhaust for a while, all that did was drown it out. I just dont see where the exhaust would cause the issue.

Theres also other weird whistling that tends to come from the wastegate (when bad) that the mechanics can never track. I would agree its a failing turbo - if it wasnt for the fact that no other "normal" failing turbo issue is seen in conjunction (varied boost, oil burning, leaks, etc).

I dont know... Like I said I havent actually replaced mine yet so I cant say with 100% certainty. I will try to do some searches, I remember reading similiar issues that were also suggesting WGA as the issue.

could it be that either of these mods will fix the issue, a WGA that is not fully open (if I understand the way a WGA works) vs. a smaller exhaust will cause restriction in a similar way wont it??

p.s. forgive the n00b logic (screwy)

 

[ViDeo^_^kiD]

I have 3 clues for you:

overly restrictive exhuast
piece of crap bypass valve which leads to funky crap w/ the wastegate actuator
terrible stock tune


My suggestion is start modding and never look back.

 

[crashkelly]

if you dont have any mods on it the stock turbo does make a screaming type sound. When I got mine it made a screaching/screaming noise, but that is just the sound a ballbreaing turbo makes. Now it might be something different because I think earlier you described it as metal on metal which might indicate shaft play. How does the noise affect performance? Or does it?

 

[SleepyMSP]

Looks like the originator is not coming back on this one so I'll just jack this a little...I personally don't notice any performance loss but then again I can tell 100% as I still am waiting to install my gauges to see what is going on (i.e. PSI drop, A/F mix over rich or whatever) but it doesn't feel like there is a loss....minus the hesitation when you get into around 5K RPM or so

 

[Spartekus]

Alright, I finally have an update on the screeching...

After i took it back to the dealership and the tech rode with me and told me it was normal...I drove it around for the weekend to see if it would go away and if it actually was a normal boosting sound...Definitely not a normal boosting sound, the noise was erratic, but always coming under hard acceleration and between 4-6.5k rpms. I also then looked under the hood at the turbo and noticed that the brand new turbo had oil on top of the shaft housing in the center...Back to the dealership....They checked out the turbo again and said the oil was just residue from the installation of the brand new turbo and that all the oil lines are flowing properly and there arent any leaks. I also rode with my service advisor and showed him the noise and he said it definitely WASNT normal and that now the lead shop tech would take a look at it. So the dealer had the car for about 2 weeks and put on all new intercooler piping and anything that looked like it could have a crack in it thats plastic. Service manager drove the car, shop tech drove the car, both said it was running great and they couldnt hear the noise. So they called me and I picked it up. Yeah, drove out on the road and pushed it hard, noise was definitely still there. I was pissed. I called them again and brought it back the next week. Drove with the service manager and he confirmed the noise. So they sent the car to another dealership in another city to have a more experienced mazdaspeed tech check it out. The guy verified the problem (screeching noise) and sent it back after trying to diagnose it, but still not being able to track it down. So now I am waiting to take the car in this friday to have Mazda's field tech look at the car...Nobody can find where the crap this noise is coming from. Everyone is saying the car is boosting properly and all lines have the appropriate pressure.

Regarding someones post about the WGA... The turbo assembly that mazda puts on these cars includes all brand new components including the WGA as far as i know.

Regarding SleepMSP's post, I can feel less power when the screeching is bad, but i can't tell if its directly related to the screech or if there are more variables at work.

I'll post an update when I hear back about the Mazda field tech's findings...Maybe we all could finally have an answer about this....

Right...

 

[Spartekus]

Oh yeah, and the dealer told me that right after they replaced my failed turbo and sent it in to Mazda so they could crack it open and see what went wrong, Mazda called my dealer and told them the turbo was fine and not failed... Crazy huh? So from what they're telling me, the screeching is not turbo failing related...Not sure if i believe it though...

 

[terbow]

if the screetching is like a whistiling, and u have a stock exhaust its cause your choking the turbo. its not a turbo failing unless its a metal on metal sound. replace ur midpipe and/or echaust with a less restrictive one and it will go away.

 

[Knox Joe]

I'm telling you it's the exhaust.