Ford Mustang Forums banner
1 - 16 of 16 Posts

·
Registered
Joined
·
381 Posts
Discussion Starter · #1 ·
i just got my FMS 65MM TB on and it whistles a little bit. does anyone elses? if it can't be fixed, it's ok, but i thought i might could adjust something to fix it. also, the idle hangs around 1200-1500 RPM for a minute before it settles back to 650. can i adjust it? what does adjusting the throttle stop screw do? that is, the one that contacts the throttle linkage and i assume the hex bolt on the other side of the TB is for idle adjustment? sorry so long, thanks.
 

·
Registered
Joined
·
339 Posts
Could it not be fully sealed.....
 

·
Registered
Joined
·
381 Posts
Discussion Starter · #3 ·
no, i think it is, there aren't any vaccum links and doesn't exude any other funny idle characteristics like surging, etc.. just hangs a bit. and if anyone can tell me what affect messing with the throttle stop screw does would be great. i assume that the hex screw on one side just lets more air into the IAC. thanks.
 

·
Registered
Joined
·
381 Posts
Discussion Starter · #4 ·
anyone?
 

·
Registered
Joined
·
1,394 Posts
my FRPP 65mm T-body doesn't whistle, and I don't have anything for your other questions... but I'll bump the post: TTT
 

·
Registered
Joined
·
605 Posts
When I got mine the idle hung too. I swapped the bypass from my stock unit onto it and that fixed that. It may cure your whistle too if the IAB is bad
 

·
Registered
Joined
·
550 Posts
The throttle stop screw does just that, stop the throttle. It keeps the butterfly from slamming completely closed when you let off of the pedal. If it did'nt do that the car would die because the IAC could not react fast enough to set an idle. Just leave the screw where it is from the factory. my E-Brock T/B whistles under light accel. also, I've never figured it out though. Does'nt seem to make a difference in the way it runs, so I'll leave well enough alone.
 

·
Registered
Joined
·
605 Posts
Idle shouldn't hang like that. Mine doesn't with that IAB replaced.
 

·
Banned
Joined
·
809 Posts
My FMS 65mm TB (just installed) whistles too. I reused the OEM gasket (couldn't find one in town and didn't want to wait for shipping) so I'm wondering if this could be the problem since I everyone says the FMS doesn't whistle. I made a new gasket myself but didn't install it since the OEM gasket didn't break. I'll try that but doubt it's the problem. Any ideas guys?
 

·
Registered
Joined
·
1,394 Posts
The gasket that came with my FRPP 65mm gasket was too big. I trimmed it down when I installed it. I have no whistle. Maybe that is what is causing the noise on your cars.
 

·
Registered
Joined
·
4,119 Posts
Is there any restriction in the opening where it meets the intake? I know when putting a 65mm TB on the GT uppers you have to port the opening a bit in one area by where the IAB port lets out (lower right) or it'll cause a whistle. The Cobra intakes may be different though.
 

·
Banned
Joined
·
809 Posts
The OEM gasket matched up perfectly with the 65mm TB so I assumed there wasn't any restriction or lip of any sort. However, that do I know. It is a stock upper so maybe I need a little port job? Just around the edge maybe to tapper it?
 

·
Registered
Joined
·
453 Posts
The idle behavior you describe is exactly what you would find if there were more air flowing at idle than needed to maintain the preset rpms. At first it will be higher, then after several seconds, the computer will drop it to around 700 or so (less fuel, I think).

I'd look for air getting in through a bad seal or a Idle Air Controller (bypass) that is sticking open. Either one could also cause the whistle.

If the throttle plate is not closing all the way at idle, it might cause the idle problem, but I can't see it causing the whistle. Adjust the screw so that the plate just closes as the cable goes to idle.
 

·
Registered
Joined
·
496 Posts
Sounds like the TPS is out of whack. That will cause hanging idle issues. I was having the same problem last week. I drilled out the metal bushings to get more play. You want around .98v at idle. Move the TPS sensor around until this is achieved. It worked for me.
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top