Turbo noise at 1800 rpm

[g.depetris]

Well i have a 2003 f-350 with automatic transmission,, i never have problems before and it has186000 miles, the things is when i push the throttle its work perfectly,, but when i slow down with the throttle closed,, between 2100 rpm and 1800 rpm it sounds like a air whispering,, the sounds is not like surge,, but its like air going out not through the turbo,, we check the hoses, silicon hoses, we changes somes, check the turbo shaft and its perfect, we check uppipe and downpipe, we test with the EBPV full open,, the sounds didnt change. i have a chip but almost 3 years until now,, and no problems of that kind before.. Thanks, i will apreciate your help.

[parkland]

Is the sound just heard for a moment, or does it do that for a while?

[g.depetris]

its sounds every time at that revs,, its vary a little at the engine cold, but it keeping doing every time, its like air going out for some place...

Thanks

[parkland]

that sounds like the EBPV is activating as it would if it was cold.

With windows down, can you hear a SSSSHHHHHH sound coming from the exhaust as this happens?

[g.depetris]

nop, the sounds come directly in front of the firewall,, there near the turbo we fix a tube that have a hole and carry the diesel, the original tube wasnt here in chile so we weld a tube with a little bigger diameter and welded over the hole to the original tube, and after that the sounds start.

thanks

[megawatt00]

Was it an intercooler tube that you welded up? If so it may just be a change in the velocity of the air at that RPM because of the different size pipe.

[g.depetris]

no it was a diesel tube, that go to feed the engine.

[megawatt00]

Is the part that you worked on in this picture? I do apologize I can't seem to figure out what part you worked on.

[g.depetris]

the tube its come out from the pump, go down close to the manifold and pass under the GPR, under the orange silicon union that goes to the engine with cold air and it enters in the back of the cylinder head.