After FAST/TB installed, loud screeching noise coming from intake
Even if that did happen, how would the engine warming up fix that issue? 
05-05-2008, 09:54 PM
#23
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Anybody figure this out yet? I just did a 92/92 intstall and Im having a very loud ticking noise coming from directly on top of the intake???? And gets louder with revs. I let the engine warm up for a while and it still ticks! Everthing is torqued to spec and in order and everything is connected?
I quess I will take it all apart and try again!
I quess I will take it all apart and try again!
05-07-2008, 07:53 PM
#26
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Ok figured out my ticking............It's the valvetrain ticking throught the thinner FAST intake! I forgot I've got the noisy a$$ Jesel rockers on there, it ticked pretty loud before the FAST and now its just a little louder.......I guess its just another noisy LS1!
05-28-2008, 05:19 AM
#31
Is it possible that this could be a tuning issue, maybe the car just needs tuned for the larger intake and T/B? Either way, I haven't been able to figure out the issue so i'm taking mine to Automotion in Louisville on monday for a complete tune and they'll check it out for me. Ill keep you guy informed of what they find.
08-16-2010, 07:59 AM
#32
I know I'm reviving an old thread, but I have the same exact chirping/whistling sound on cold startup. It's directly related to the IAC location. If my IAC counts are above 150 (typical on cold startup), it will make a loud chirping/whirring/whistling sound as you can hear in the video below. I have a FAST 90/90 combo, so does anyone have any pics of the changes needed to be made to the IAC opening? Thanks.
http://www.youtube.com/watch?v=YFRVsD8XXkI
http://www.youtube.com/watch?v=YFRVsD8XXkI
08-21-2010, 07:05 AM
#33
If the whistling is only the air coming through the IAC passage, then perhaps getting more airflow in through the TB blade will help the IAC motor close the IAC passage more and reduce the whistling?
The tuner for my LS3 indicated IAC's should be between 45-75 at hot idle (185+). You allow more air in by cracking open the throttle stop screw a little bit and/or by drilling the TB blade hole slightly larger. If you move the screw too far and your TPS% is >0.4%, even randomly, reset your TPS position. It might take a few tries to get it right. If you move the screw too far, then the TPS won't reset. I seem to had the best luck not going more than 2% at a time.
Or if you're in the camp that doesn't mind adjusting their blade hole opening, try drilling it out an additional 1/32" at a time.
The tuner for my LS3 indicated IAC's should be between 45-75 at hot idle (185+). You allow more air in by cracking open the throttle stop screw a little bit and/or by drilling the TB blade hole slightly larger. If you move the screw too far and your TPS% is >0.4%, even randomly, reset your TPS position. It might take a few tries to get it right. If you move the screw too far, then the TPS won't reset. I seem to had the best luck not going more than 2% at a time.
Or if you're in the camp that doesn't mind adjusting their blade hole opening, try drilling it out an additional 1/32" at a time.
08-21-2010, 02:34 PM
#34
I hear what you're saying Jim, but hot idle and my IAC counts are in the 35-50 range. If I crack open the throttle body any more, or drill the hole larger, it's going to drop the iac counts even more.
This isn't a huge thing, it just sounds like I have a procharger for the first 30-40 seconds on a cold startup when the IAC is open. Maybe I'll drop the cold startup rpms from 1100 down to 1000 and see what that does. I don't want to just start 'porting' my throttle body because it's making a sound.
This isn't a huge thing, it just sounds like I have a procharger for the first 30-40 seconds on a cold startup when the IAC is open. Maybe I'll drop the cold startup rpms from 1100 down to 1000 and see what that does. I don't want to just start 'porting' my throttle body because it's making a sound.
08-22-2010, 08:12 PM
#36
Sorry, let me clarify, cold startup has the idle rpm set to 1100, but then warm idle is set to 800. So at a startup, the iac opens to ~160-180 to keep the rpms that high, then it settles down to 35-45 when the temperature comes up and rpms settle in to 800. What I meant to say ws that I can probably reduce the cold startup rpm down to 1000 rpm.
