Funny noises.

DarkShadowFord

DarkShadowFord

Forum Member
So we installed Comp cams, TFS intake elbow, TFS 75mm throttle body, BBK ceramic longtube headers, BBK cated x-pipe, and Magnaflow mufflers on my 2003 mustang gt, it already had a BBK CAI, the install went almost perfect, the only issue we came across is that when I drive down the road under load and shift I get a strange sound, almost like a blow-off valve. I can't just open my hood and rev up and hear it, I only can get the sound on the street under load usually above 3k rpms. I went back through the engine and looked for any vac leaks or anything loose, didn't help though. Car drives great, a bunch more power above 3500rpms, just a strange sound when I let off the gas, not too loud, but still, noticable. Does anybody have ideas on this strange sound? Thanks for the help/advice/information.
 
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I can't really tell if it is sucking air or pushing it, but if you mean the Idle air control valve, I could try taking that off and cleaning it. Is the IAC valve that same thing as an IAV valve or is it something else? I read about if a car stalls unexpectedly that some times it could be a stuck IAC valve, and my car has done that a couple times but I never really thought twice about it, hmmm.
 
In some of my previous cars with extensive intake mods.....you can hear the air backing off the throttle plate when closed and out the intake.....can sounds similar to a BOV only not near as pornounced......If it is LOUD liek a BOV would be that is very strangs issue...check IAV
 
In my experiences with the throttle body upgrades in mine and other cars, at certain points the throttle blade will make a whistle, kinda sounds like a turbo. I beleive its just the air rushing across the throttle blade and i wouldnt worry about it
 
Ya, it is not so much of a whistle, I kind of expected something like that, but it don't show up. this sound is just after letting off the gas, a kind of quick pulsing sound, the only thing I can compare it to is a pulsing wastegate or blow off valve, I wouldn't think that a NA car could develope any kind of pressure like that? When we first did the install we just had the new intake elbow on with the stock throttle body, because it got back ordered, and it made that sound, then we put in the new throttle body a couple days later, and it made the same sound. After work if it ever stops raining I am going to try and clean out the iac and hopefully that works. The sound isn't too annoying but it's not a sound I want the car to make haha.
 
Well, I cleaned out the IAC today and no luck, still have the sound. Glad I cleaned out the IAC though, it looked like it could have used it, much cleaner now.
 
DarkShadowFord said:
and how bad would this senario be for my car? any way to fix it?
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If that is the issue, that is a pretty normal occurance and nothing to worry about, ford engineers lots of "air silencing" materals into there factory intake systems for driveablility. When performance intakes mods are installed it makes that air that is rushing in and out more noticable......If you are still concerned about this issue, have a trained tech take a ride with you to confirm this threory.
 
have you had the car tuned since all of the mods... could have something to do with that... call livernois or alternative
 
The car has not been tuned, we expected to see it running lean after all the intake and exhaust mods +cam, using the #21 injectors and the factory tune. We were going to put on a wideband that we have but after looking in the xpipe last weekend everything looks like it is running very well, not lean at all. I am 90 percent sure I will tuning it either way in march next year, so I only need the factory tune to last untill the snow starts coming again. Livernois wants 600$ for a tune, I dont know what Alternative is pricing.
 
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