Screeching at WOT

[ChvyKc]

This has been going on for at least a couple week now and I can't figure out what the problem is. The last time that I took the car out, everything was fine for about ten minutes of riding. During that time, I did a third gear pull and the car pulled hard just like it was suppose to. The next pull that I did the car makes a loud screeching noise all the way to redline and it feels like it is loosing power. Well, I finally got around to pulling the inlet hose off and checked the turbo because it kind of sounded the same as when my 14b crapped out on me. I found no shavings in the turbo and very very little shaft play.

One thing that I was thinking that it could be was the alternator. I have heard the bearings in an alternator go bad before and it sounds like that. The only difference was that those alternators did it all the time and mine only does it during WOT. I was thinking that the bearings in mine are going bad and under full throttle they are producing more of a strain on the motor which would make it lose power.

If anybody has anymore ideas, I will be glad to hear them. I just want to get this fixed so the car runs right. I am planning on pulling the AC system soon so if it is the alternator, I would like to go ahead and change it out while I am in there.

 

[BISHILVR]

My vote is bad turbo. Shaft play is'nt the only thing that can happen to a turbo.

 

[ChvyKc]

My vote is bad turbo. Shaft play is'nt the only thing that can happen to a turbo.

I really don't think that it's the turbo, it very well could be though. I just went out there and double checked the turbo again after you posted that and it spins freely and like I said before there is has almost no shaft play at all. What would make the bearings screech just after a certain amount of run time and not right after I start the car up?

I'm confused Thanks for the help though, let me know if you got anymore ideas.

 

[98eclipseRS]

My guess would be the turbo as well but since you said you already checked it I am going to take your word for it that its good. Have you checked for boost leaks. A larger one will have a more noticable sound and if the car feels like its loosing power that could quite possibly be it. Have you been hiting fuel cut since the sound? Does it happen any other time?? When my t25 went bad it made a crazy howling noise under full boost. One last thing I could think of it being is a belt slipping under the extra stress and rpms it is seeing.

 

[BoostedWilk]

My guess would be the turbo as well but since you said you already checked it I am going to take your word for it that its good. Have you checked for boost leaks. A larger one will have a more noticable sound and if the car feels like its loosing power that could quite possibly be it. Have you been hiting fuel cut since the sound? Does it happen any other time?? When my t25 went bad it made a crazy howling noise under full boost. One last thing I could think of it being is a belt slipping under the extra stress and rpms it is seeing.

Thats what I was thinking....had the same problem in my avenger....you sure you dont have the eclipe gtr version which came with a supercharger instead of a turbo?

 

[BISHILVR]

I really don't think that it's the turbo, it very well could be though. I just went out there and double checked the turbo again after you posted that and it spins freely and like I said before there is has almost no shaft play at all. What would make the bearings screech just after a certain amount of run time and not right after I start the car up?

I'm confused Thanks for the help though, let me know if you got anymore ideas.

Well you say it only happens at w.o.t. which is when the turbo would have the highest load on it. Even though it does'nt seem to have much shaft play or the wheels still spin, you figure that even a little bit of drag on the wheel gets amplified exponentially as the turbos rpm's rise. Figure that thing spins at close to 100,000 rpm at times.

 

[98eclipseRS]

Now that I think of it, I have seen many a stock t25 with almost no shaft play on the comp side of the turbo but when you pull off the o2 housing the exhaust side of the shaft+wheels was all over the place.

 

[dsmsucks]

Another vote for the turbo

Mines was doin the same thing when I put my turbo back on. The blades was rubing against the turbine housing.
I would take off the intake hose and o2 housing and see if the blades are touching!!
If they are and you been drivin like that for a couple of weeks I wouldnt be surprised if you have some damaged blades

 

[ChvyKc]

My guess would be the turbo as well but since you said you already checked it I am going to take your word for it that its good. Have you checked for boost leaks. A larger one will have a more noticable sound and if the car feels like its loosing power that could quite possibly be it. Have you been hiting fuel cut since the sound? Does it happen any other time?? When my t25 went bad it made a crazy howling noise under full boost. One last thing I could think of it being is a belt slipping under the extra stress and rpms it is seeing.

I haven't been hitting fuel cut. I know the sound that you are talking about when the turbine wheel is scrapping the housing. That is exactly what my 14B did before it went out, but this doesn't sound like that. I had a buddy ride in the car with me and in his car beside me while I spooled the turbo at WOT and he said that it didn't sound like the turbo either. There are just so many noises going on up there, it is hard to figure out what it is.

I also had a problem with the belt before. I know what that sounds like also. The bolt that pulls tension on the alternator belt is missing from my bracket and I have to pull tension on it and then tighten the bolt while holding tension on the alternator. There is a brand new belt on there right now (less than a month old) and the belt is tight (I just tightened it up two weekends ago)

I guess that I am just going to have to do some looking around. I am probably going to pull the turbo when I get ready to pull the AC so I can take the 02 housing off and check the other wheel. If the other wheel is fine and there are no signs that it is hitting the housing then can I be sure that it's not the turbo?

Just to give you some more background on the turbo. It has right around 10,000 miles on it. I bought it from a close friend that bought it straight from forced performance. It has always been turbo timed. It came straight off his car and right onto mine, so I know that it has been taken care of. He never had any problems with it and was actually able to make 330 whp on it before his tranny gave out on him. I mean, I have had 12A's that I put on Starions at 18 pounds with more shaft play than that and had no problems with them for at least another 5,000 miles. I haven't even put 1,000 miles on this turbo since it's been on my car.

 

[oldman]

Doesn't hurt to check your crank pulley for signs of separation. I would also replace that alternator tensioning bolt asap, the lock bolt alone will not be sufficient.

 

[Defiant]

^ ^ ^ Beat me to it. Harmonic balancer.

 

[ChvyKc]

Doesn't hurt to check your crank pulley for signs of separation. I would also replace that alternator tensioning bolt asap, the lock bolt alone will not be sufficient.

Will do, never thought about the balancer or the pulley going out on me (guess that's why you two are moderator/wismen and I'm not ).

I planned on ordering that bolt. I have a hook up at the local dealership so I am going to pick one up today and get everything back on there right, thanks for the help guys.

 

[ChvyKc]

I ruled out the alternator, water pump and power steering pump just now. I guess that it's not looking any better for the turbo.

I did take a look at the crank pulley and the rubber that connects the inner and outer parts of the pulley looks good. I didn't see any cracks in it. I am going to pull the turbo off this weekend after I do a boost leak test and see what the turbine side of the turbo looks like. If the turbine wheel looks good then do you guys think that it could still be the turbo? If not, what else could it be?

 

[Defiant]

I did take a look at the crank pulley and the rubber that connects the inner and outer parts of the pulley looks good. I didn't see any cracks in it.

Mine looked perfect. It had no adhesion between the outer edge of the rubber and the inside of the outer rim. Put a chalk mark from the side of the rim to the hub, and see if it moves out of index.

 

[ChvyKc]

Mine looked perfect. It had no adhesion between the outer edge of the rubber and the inside of the outer rim. Put a chalk mark from the side of the rim to the hub, and see if it moves out of index.

Got ya, I am going to fix that retainer bolt and put another belt on the car and make a mark and see if it moves. The bottom end of the motor has over 160,000 miles on it, so that pulley probably needs to be replaced anyway.

 

[napkinthief]

My power steering belt screeched during high rpms, I just got a bottle of belt conditioner and some wd-40. conditioner goes on the belts, wd-40 lubes all the pulleys attached the belt. my car sounds weird without the screeching i bought it with almost a year ago....I like it though, quiet

 

[ChvyKc]

My power steering belt screeched during high rpms, I just got a bottle of belt conditioner and some wd-40. conditioner goes on the belts, wd-40 lubes all the pulleys attached the belt. my car sounds weird without the screeching i bought it with almost a year ago....I like it though, quiet

I thought that it was my AC belt because it was rubbing the timing cover, but I ruled all the belts out and the AC belt isn't even on there anymore and it still makes that noise. I am going to run a boost leak test next and see how that turns out. I got to spend some time with the family today though, so it will probably be next weekend before I can do anything.

Defiant, I put a mark on the pulley like you said and drove the car for about 15-20 minutes and it didn't move. Is it suppose to take longer than that or is the pulley ok?

 

[ChvyKc]

Alright, I know that this thread is a little old, but no reason to make a new one for the same reason. I thought that I had found the problem. I made a boost leak tester and found that I had a huge boost leak at the TB. I bought new gaskets and I also replaced the TB shaft seals. I got everything back together and got the car running again last night with no more boost leaks. When I drove the car to work today, it did the same thing. It ran great for about 15 minutes. After that time, the cars starts to make a loud screeching noise at WOT.

I did like Defiant suggested and made marks on the crank pulley. It has been like that for about 2 hours worth of driving (this is not my daily driver) and it hasn't moved. I have also been talking with one of the guys at www.turbochargers.com to see what the thought of the turbo and he said that he doubted that it was the turbo at all.

I did some playing around with it before I took the TB off. I took the boost controller off and just let the car run 9 pounds of boost. I drove from Gilbert (about 30 minutes away) with no problems. I couldn't get it to make the same noise. When I got back home, I put the boost controller back on and turned it up to 16 pounds and still had no problems. Got out, turned it up to 19 pounds and it started doing it again. It also did it when I went back down to 16 pounds, but stopped when I took the boost controller off and just ran 9. I also wanted to add that it doesn't really sounds like it is coming from the turbo, it actually sounds like it is coming from the driver's side of the car where all the belts are.

Anymore suggestions I would really like to get this figured out so I can start working on getting an itercooler upgrade together.

 

[ChvyKc]

I also wanted to add that I finally got an e-mail back from FP and the guy said that it could be "axial" shaft play in the turbo, whatever that means or a boost leak that is not related to the turbo. Since there are no more boost leaks and if nobody has anymore suggestions then I am going to pull the turbo down this weekend and take a look at the turbine wheel to see if there is any shaft play on that side of the turbo.

 

[BISHILVR]

Did you boost leak test everything at 20 pounds??? If you did'nt you should. Maybe you have a intake manny gasket going bad and leaking at high boost only???

 

[ChvyKc]

Did you boost leak test everything at 20 pounds??? If you did'nt you should. Maybe you have a intake manny gasket going bad and leaking at high boost only???

I thought about that last night, I only tested it up to 14-15 pounds which doesn't make any sense because I have no problems there. My g/f has to work tonight so I will have some time today to do another boost leak test to see how it does at 20 pounds.

 

[dnhieu]

does it make a howling noise or does it make a screeching noise. the noises are totally diffrent and obviously mean two diffrent things. i bet if its making that howling noise that its the turbo and you need to replace it. its really not that difficlut of a job and is worth taking the time to take it off and putting it back on.

 

[ChvyKc]

does it make a howling noise or does it make a screeching noise. the noises are totally diffrent and obviously mean two diffrent things. i bet if its making that howling noise that its the turbo and you need to replace it. its really not that difficlut of a job and is worth taking the time to take it off and putting it back on.

Yeah, pulling the turbo is not that big of a deal, I have done it plenty of times. The hard part is finding the time to do it. I am definately going to pull it off and check the turbine side of the turbo, but I am going to do a boost leak test before I pull it off to see how the intake manifold is doing at 20 pounds.

 

[ChvyKc]

Did another boost leak test and found something that I have never noticed before. It looks like there is a very very small hole in one of the fittings that goes into the side of my Hallman MBC and it is leaking boost like crazy above 16 pounds. Anybody know if that is suppose to be there and if not any suggestions on how to plug it?

It is in the part of the fitting that you would put an open end wrench on to tighten the fitting into the boost controller. It actually looks like someone drilled a very very small hole there and I have never noticed it before.

 

[oldman]

Step one in leak testing is to disconnect the mbc or turn it all the way in. The bleeder hole is suppose to be there, it releases pressure in between mbc and actuator after the ball in the mbc moves back towards its original position blocking the path, this is to prevent pressure getting trapped causing the wastegate to stay open in between shifts or re-accelerating immediately after letting off.