Help w/ noise

[Sy#1991]

I have a popping/knocking noise on steady cruise under no boost. As soon as I am into boost it goes away. If I blip the throttle or find a steady rpm the noise is very apparent. I was listening around with a stethoscope and it almost sounds turbo related. The shaft does have slight up and down play but the blades on both sides look good (I removed the o2 and bore scoped the exhaust side). The blades are straight and have no bends or chips in it. All help and info is greatly appreciated thanks.

 

[Sy#1991]

Re: Help w/ noise

Forgot to add the truck is almost bone stock. Only upgrades are borla cat back, IC pump hot wired, rubber IC lines, silicone lines, NGK plugs, taylor wires, msd cap, rotor, and coil.

 

[jaystcb]

Re: Help w/ noise

Just a hunch. But check the brackets that hold the upper inner cooler on. a bolt could have fallen out and you are hearing the bolt bouncing around in the engine bay.

 

[Sy#1991]

Re: Help w/ noise

Just doubled checked it and they are all tight.

 

[Sy#1991]

Re: Help w/ noise

Any other ideas or anyone in the area have time to stop by and take a listen.

 

[bezerk]

Re: Help w/ noise

exhaust manifolds?

 

[Sy#1991]

Re: Help w/ noise

I thought that the manifolds could be a possibility but there are no black exhaust marks by the manifolds. At times you can hear it through the cross pipe underneath. With a stethoscope on the manifolds themselves you really can't hear the noise.

 

[Damian]

Re: Help w/ noise

What type of noise is it? What does it sound like?

 

[bezerk]

Re: Help w/ noise

there is a valve in the brake system to pull vacuum. if you search for quaak qwak or hower you call it over there.
people had that sympton before.

 

[Sy#1991]

Re: Help w/ noise

The noise is definitely on the passenger side and it almost sounds like a rod knock. I was thinking if it was a rod knock it would make the noise all the time. It only makes it on light steady throttle or if you blip the throttle at a certain rpm. There is absolutely no noise at idle or before boost and into full boost. It runs to strong for a bad rod bearing.

 

[Sy#1991]

Re: Help w/ noise

I would think if the turbo was bad it wouldn't build full boost but it does. Unless the bearing inside the turbo is bad but i would think it would make the nose all the time. The noise also sounds like a broken rocker but i had the covers off and they all looked good.

 

[Sy#1991]

Re: Help w/ noise

Have not had time to look at the truck but today I ran it for a little bit and the noise almost sounds like it's coming from the exhaust cross pipe. Any ideas anyone?

 

[Slyclone]

Re: Help w/ noise

Possible you hit a pot hole, swallowed your tire, jogged your suspension and could have very well cracked your header, or atleast cracked your cross over. Look for black soot.

 

[Sy#1991]

Re: Help w/ noise

Looked all over with a mirror and no soot seen. The truck is hardly driven and low mileage

 

[Sy#1991]

Re: Help w/ noise

Where are the common areas for the manifolds or cross pipe to crack? Thanks

 

[Sy#1991]

Re: Help w/ noise

Can photobucket host videos? If not what is a good video host? I have some video of the noise I have.

 

[Slyclone]

Re: Help w/ noise

Yes Photo Bucket will host- It will be a img code but it will link us to your video page. I did it last week here on a boost gauge issue/map issue