Wastegate Stuck - does it matter ?

[rhodes2010]

1996 GSX Turbo - stock motor. Cast iron exhaust manifold has a vaccum
operated pod with arm going to what looks like a wastegate actuator.

This arm is frozen solid. Cannot move it. Tomorrow I will remove the connector
and see if the thing opens and closes.
I suspect it will not.

So I probably have a frozen wastegate. Does it matter ?
Car runs good, passed smog.

If I were to fix this I assume I would have to remove the exhaust manifold.
Is this true ?

 

[Junfan]

If it is stuck up then your car is not really making boost. I would suggest you fix the problem so the car will make boost properly and then the wastegate will open when needed to not overboost the car.

Of it could be even worse. The wastegate could be stuck closed causing the car too overboost. It will run great for a while and then basically destroy itself.

 

[adidasdudegst]

Yes it does matter, I would get that fixed soon. You are basically going to be maxing out the turbo otherwise and putting lots of strain on many parts under the hood

 

[rhodes2010]

Okay. I will definitely test the wastegate and make sure it works.
Several posts said they may not stick, just hard to move by hand.
I will remove the actuating rod and test the movement.

But help me understand this : why a wastegate and a blow off valve ?
I look at both as blowing off excess pressure.
The blow off valve blows off excess air that has already been measured by the maf and recirculates it.
The wastegate blows off excess pressure through the exhaust system.

Why do these cars have both ?

By the way, our max boost has been 13psi or so. Seems reasonable and
makes me think we are safe. Makes me think the wastegate works.

 

[davidalindsey]

Wastegate- this controls the amount of boost your running in your turbo. (It limits the amount of exhaust gasses running into the turbo by a valve which bypasses the turbo and straight out the exhaust.)
Blow off valve - this releases pressure in the intake system when the throttle is closed. (When the turbo spools and air is being forced into the intake and the throttle is closed the b.o.v opens and the air is released pushhh..)
Any turbo charged vehicle requries both a wastegate and BOV.

Simply a wastegate goes between the exhaust manifold and the turbo and diverts exhaust gases from the turbo to stop it from building boost. A BOV goes between the turbo and the throttle body so that when the throttle plate closes the boost is vented and not be forced back towards the compressor.
And 13 psi is fine max would be 15psi, I would no do the max untill you get some way to monitor knock.

 

[yepes281]

Your not going to be able to move it by hand.

A wastegate controls how much boost your turbo makes.

A blow off valve releases excess boost in the intercooler piping after the throttle body closes.

Why do you think its stuck open?

 

[crash89]

^^^ What they said! Mine stuck closed once and I kept overboosting (20 psi ish) and kept hitting fuel cut badly. I couldnt figure it out for the life of me. Then found that the flapper seized shut was the culprit. Some WD40 and a hammer and about 15 minutes later... FIXED! You wont have to really remove anything except the fans and the actuator arm to test if the flapper is seized.

 

[davidalindsey]

One time my wategate arm came off of the flaper by the pin missing.
So my flaper was open creating no boost. I fixed it by finding a picture frames nail and sticking it in place of the pin.

Also here is a good article to read:
BLOW OFF VALVE vs WASTEGATE

 

[300hpbound]

The waste gate is there to basically monitor the turbo itself. if its building more boost because that waste gate isn't there, it would continue building and eventually just tear up the turbo, fins and all.

As far as the blow off valve, not all of that air that is being compressed is actually used. When you go to shift, theres still excess air in the intercooler and pipes. So to decrease the risk of over-pressurizing the intercooler the blow off valve lets the air that's between the turbo and the engine out, creating a clear pathway for new, compressed air

 

[yepes281]

One time my wategate arm came off of the flaper by the pin missing.
So my flaper was open creating no boost. I fixed it by finding a picture frames nail and sticking it in place of the pin.

Also here is a good article to read:
BLOW OFF VALVE vs WASTEGATE

picture frame nail...

 

[davidalindsey]

picture frame nail...

Yep, I just bent the nail around it. I could'nt find anything else, so far so good.

 

[mcneilmg]

Yes it does matter, I would get that fixed soon. You are basically going to be maxing out the turbo otherwise and putting lots of strain on many parts under the hood

The exhaust pressure will not max/stress out the turbo like one would think but the major problem lies within the compression in the cylinders pushing the rotating assembly much harder than the stock assembly would like to see. good luck.Mike

 

[mcneilmg]

agreed musta been having a cold one

 

[jtmcinder]

By the way, our max boost has been 13psi or so. Seems reasonable and
makes me think we are safe. Makes me think the wastegate works.

Yep. Odds are, you simply aren't yanking hard enough on the actuator arm. Not that I'm suggesting that you yank any harder. I'm merely saying that I'm not convinced that your wastegate is actually stuck.