Wastegate not working properly?

berryl

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After I installed my DIY Air filter I heard a lot more noise coming from under the hood, which is great. But I am now hearing a noise that I'm not sure is so good. I guess the best way to describe it is a PSHOOOOO sound, starts out louder then tapers off. It happens when I accelerate fairly hard and the tranny shifts and only lasts for just a brief second. It also happens when accelerating up a hill, when this happens it will do it as long as I keep my foot in it. At first I thought it might be turbo surge but now I'm not so sure. I pulled the red vacuum line off the wastegate solenoid and hooked up a vacuum pump and no matter how much vacuum I applied the rod coming out of the solenoid does not move. I also can't move the rod by hand either. Is that right? If it should move and it doesn't could the wastegate be stuck partially open maybe allowing boost to escape under load? If the actuator rod should move by hand how does a person fix it or what would be the most likely culprit? I did notice while checking things under the hood ie. CAC boot clamps, looking for leaky boots, etc. that the green vacuum line going to the intake tube coming from the air filter was disconnected so I reconnected it and it made no difference. All CAC boots appear to be in good shape and all clamps tight. Being new to diesels and turbos I am kind of at a loss hoping for the expertise of everyone on here to steer me in the right direction. Thanks in advance and sorry for being so long winded.
 

CSIPSD

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Its called a shift bark... You couldnt hear it with the old intake set up... Semi harmless.

The second sound sounds like surge, you can down shift to get the turbo back in the proper map, or add a ATS housing to stop it. The wastegate rod is VERY hard to move by hand, but you will never really hear the wastegate open....
 

Hoss 350

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berryl said:
After I installed my DIY Air filter I heard a lot more noise coming from under the hood, which is great. But I am now hearing a noise that I'm not sure is so good. I guess the best way to describe it is a PSHOOOOO sound, starts out louder then tapers off. It happens when I accelerate fairly hard and the tranny shifts and only lasts for just a brief second. It also happens when accelerating up a hill, when this happens it will do it as long as I keep my foot in it. At first I thought it might be turbo surge but now I'm not so sure. I pulled the red vacuum line off the wastegate solenoid and hooked up a vacuum pump and no matter how much vacuum I applied the rod coming out of the solenoid does not move. I also can't move the rod by hand either. Is that right? If it should move and it doesn't could the wastegate be stuck partially open maybe allowing boost to escape under load? If the actuator rod should move by hand how does a person fix it or what would be the most likely culprit? I did notice while checking things under the hood ie. CAC boot clamps, looking for leaky boots, etc. that the green vacuum line going to the intake tube coming from the air filter was disconnected so I reconnected it and it made no difference. All CAC boots appear to be in good shape and all clamps tight. Being new to diesels and turbos I am kind of at a loss hoping for the expertise of everyone on here to steer me in the right direction. Thanks in advance and sorry for being so long winded.
The noise when you shift is perfectly normal. it made it before, too, you just couldn't hear it because the stock airbox acted like a baffle muffler and stopped the sound.

All it is is boost bleeding back out the intake (reversing) from the shift. The turbo doesn't spin as much after a shift, and the engine also has less demand for air, so that leaves a surplus of compressed air after the shift, and the air coming in behind it is no longer pressurized enough to prevent a reversal (since the turbo has spun down) and so the air whooshes back out the intake.

It sounds cool, IMHO, and if you listen, big rigs do it, too!!!
 

berryl

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Thanks for the info guys, now I am getting curious. So is turbo bark just a mild form of surge? What exactly does surge sound like? I thought I had a pretty good idea but now I'm not sure any more. If I had a boost gauge would I be able to tell the turbo was surging by watching the gauge? Sorry for all the newbie questions.
 

CSIPSD

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A boost gauge will start to bounce around when your surging, around 15 psi on most trucks. Bark is just a form of stall, just like the explanation above.
 

SMOKNZ

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berryl said:
I pulled the red vacuum line off the wastegate solenoid and hooked up a vacuum pump and no matter how much vacuum I applied the rod coming out of the solenoid does not move. I also can't move the rod by hand either. Is that right?

Every Wastegate that I have ever seen (intergral, and stand alone units) uses positive pressure to actuate, not vacuum. Try using a pressure regulator and slowely increase the pressure to the wastegate actuator, it should move. The gate should start to open around 5 psi, and should take a few more psi before fully opening. Also there is a spring in the actuator that will make moving the rod difficult.

Bill
 

CSIPSD

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Duh.. I miss that, yes, got to put some pressure to it!!! LOL
 

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