I have a 87 TII with a motor I'm breaking in so no boost yet.

Sometimes during idle (once warmed up) and during decelaration I hear a noise coming from the turbo manifold.
It sounds like metal tapping like the exhaust is rattling but it's not.

I jacked up the car while idling and it is coming from inside the exhaust.

Any ideas?

 

are you sure its not the tranny? push in the clutch when you hear it then let out. see if anything changes.

 

Does it get louder of faster when you give it gas?

 

It's not the tranny it does it in nuetral as well as in gear.

It only does it during deceleration and sometimes idle, when I push the accelerator it stops.

 

I have my stock BOV vented to the atmosphere because I have a custom TID (to4 hybrid turbo).
BTW I have a one way check valve on it.

Could this have anything to do with it?
Maybe small backfire during deceleration?

 

^

 

That would be my guess.

 

Do you have yours vented to atmosphere?
Any problems like this?

Anyone?

 

The tranny is still spinning while its in nuetral, its just that no gear is selected to rotate the output shaft so don't rule out a main tranny bearing unless its the same tranny and a new motor. You say you're breaking this motor in. Did you ever drive the car before the rebuild or motor replacement? If you drove the car before and it did not do this, then I would discount the tranny.

 

thats what im saying because my tranny makes that damn noise. but if i push in the clutch it goes away.
if i give it gas it stops as well. its because the shaft isnt being thrown around when u rev it, meaning no vibration. does this sound correct?

 

The noise only comes when the car is warmed up.
If it was a tranny problem I think it would do it all the time.

Also I can hear it coming from the manifold.

Any ideas?

 

^

 

Could this be compressor surge since it's only during decelaration and idle somtimes?
Can you get compressor surge when at idle or low rpms?

Anyone had a problem with surging when venting stock bov.

 

I remember in reading a tech article in racing beat catalog, and they say that sometimes the exhaust insert can work itself loose, and rattle. I believe they also said it would do it just off idle, and on accel and decel. This sounds exactly like your problem, I would unbolt the turbo and manifold and see if the inserts are still solid in the housings. I bet that is what it is.

 

I'm refering to the inserts in the aluminum housings for the exhaust port. To clear up any confusion..

 

That might be it thanks.
I really didn't want to have to unbolt my turbo
But I might have to.

Any other ideas?

 

Still got this damn noise it's driving me crazy.