Whistling noise from engine
 

Hi Everyone,

In my quest to track down the cause of a low boost condition, I noticed that when idling, if I blip the throttle and from idle to about 1500ish RPM's, I hear a whistling noise that changes pitch along w/ the RPMs..

I'm ordering a whole new set of turbo/intercooler/pipe seals and O-rings in the next day or so, but wanted to run this by the experts out there in the event I should order another part.

Cheers

Check the hose from the IC to to the wastegate, make sure it isn't loose or disconnected. Also, check the one to the WUR.

Check the boost pressure recirculation valve/piston assembly. Each end has a cap with a rubber gasket behind it. If leaking, it could also cause your low boost symptom. Tell-tale signs of the gasket(s) failing would be an audible clicking sound everytime you get on and off the throttle quickly. The piston inside the assembly is vacuum actuated and the gaskets act not only as seals, but as a cushion for the piston to strike against.

Thanks guys.. I did some digging and the whistling noise goes away once the car is warmed up.

I found out I've got a a manual boost controller which I'm trying to sort out (new post) to determine if this is causing any issues.

The MBC was set to the highest boost and the car developed about .7/.8 bar and spiked to 1.0 between shifts.

I dialed it back all the way (lowest setting) and it seems like the car gets to about the same .7/.8 bar but does so less quickly and doesnt seem to have that big spike.

Also, FWIW, when the MBC is set to the lowest point the accelleration seems smoother off the line wheras when it is dialed up, the car seems to bog just a bit.

In any event, I'll order the gaskets for the recirc valve.

Thanks for the tip.

Here's a link to a diagram of the recirculation valve and gasket, in case you're not sure where to look.
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=930-110-149-00-M17&catalog_description=Seal%2C%20for%20Air%20Valv e%20Housing%20%28Boost%20Valve%20Housing%29%20%28% 32%20per%20car%2C%20sold%20per%20each%29%2C%20%39% 31%31%20Turbo%20%28%31%39%37%36%2D%38%39%29%20