High pitch noise from motor being sent out air filter, not sure what it is?

[black97GSX]

My 97 GSX was in an accident about 2 months ago, involving deer, after doing tons of work to it like, 1G block swap, internals, turbo, fuel system . The car is finally up and running after about 2 months, and a new apexi skyline FMIC and a bit of exterior work. At first was running shitty, sputtering when it was about to hit boost, but i messed with the SAFC and just let the motor run for a while and then started running better. I guess the injectors and plugs didnt like the 2 month old gas very much. Even though the motor was running better there was still a high pitch beeping kind of noise coming from the air filter. I know it wasnt coming from the air filter only, but it had to be coming from someplace else in the motor and being sent out the air filter. Have never heard this on my car before or even heard it happening on other DSMs. Not sure at all what it could be, will check it again tomorrow, if you guys have any ideas or info that would be helpful. Hopefully it will just stop on its own. Later

 

[black97GSX]

I don't think its a boost leak, i checked a lot of places. I guess ill go over my intake and my intercooler piping again with soapy water to see if i missed anything. Ill probably going around to see if there are any vaccuum hoses disconnected too. Its a really weird noise, something i havent heard before from a boost leak. Its like a mix between high pitched beep, hissing and a little whistling. You can hear it by just standing in front of the car but if you put your ear by the motor its the loudest right at the air filter.

 

[Defiant]

Bizarre. Get 5' of vacuum hose, hold one end up to your ear, and trace over the whole engine with the other until you find the source.

Make sure it's not a blown harmonic balancer.

 

[BISHILVR]

blowoff valve....especially if you still have the stock plastic one and its been in an accident....

 

[black97GSX]

i don't think its the BOV, because i dont have the stock 2G one anymore. I have the stock 1G and that one is metal and can hold up to a lot more then the 2G. My car is on low boost right now and running 18 psi with the stock 1G BOV, and its holding it perfectly mine. But you never know maybe something is wrong with the BOV so i still check it out. Thanks for the idea man.

 

[el aguila]

Under VERY light throttle, my car will make a beeping noise sometimes. It's hard to replicate it but I've narrowed it down to the BOV.

 

[1Quick99GST]

I have a 1G BOV as well, and when I let off the gas anywhere from 10in of vacuum to ~3lb of boost, it squeeks (beeps...whatever). If I barley let off the gas while still in vacuum, it hits several different pitches and sounds like a goddamn windchime or something. Kind of annoying, but I've gotten used to it. This all began right after I did my upper IC pipe / 1G BOV and I'm certain it's the BOV that's making the noise. It sounds normal if I hit a decent amount of boost, otherwise it makes that squeeky noise. Maybe it's just the way the air is passing out of the BOV and through the return tube? Hope this helps - for what it's worth, at least you know you're not alone.

 

[black97GSX]

Thanks for all the info guys. Ill check out the BOV hopefully thats it, so i wont have to worry about it that much anymore. Ill check it out tomorrow and see if thats it, if not ill keep checking stuff out to see what it is. later