Boat Horn sound for airbox

Burns Z

Registered User
I just went to get my oil changed,2 new back tires, and to have my A/C recharged.. When I got in my car after all the work was done, the car was idling around 2000 rpm, after taking it down the road, it quit doing that and the idle is at 800 now, but when I turn the car off,as the boost gauge is going back down to 0, it makes a loud boat horn like sound for about 1 second from right around the airbox. I haven't had a chance to check around the area yet, because i had all the work done on my break...Just curious to see if anyone else had any kind of problem like this before and what caused it..Thanks Guys....By the way my car is a 90 5 speed SC
 
HMM

Does you SC idel high?? because i had a problems a couple of weeks ago, and my car ideled at 2500rpms and when i shut it off and sometimes when it was running it would make a boat horn nosie....

that problem you might be having is your IAC idel air control valve monted on your T.B..it fixed it right up;

Good luck
-JERRY-
 
I concur.. an altered idle and howling noise upon shutdown are almost always symptoms of a bad Idle air control valve IAC. Replace it only with an oem Ford part, the aftermarkets must be mounted in reverse to work, and with the oil <strike>dipstick</strike> fill tube, they won't fit.
 
Last edited:
i am new to the sc but how is the oil dipstick in the way of the iac?? isn't the iac mounted to the throttle body? i think mine is also bad but i was not sure exactly where it was. now i am more confused... Bill
 
Oil filler tube on the valve cover is in the front of the TB. It prevents most aftermarket IACs from being usable as they require you to flip it over 180 degrees. So instead of it pointing backwards, it points forwards and won't fit. I've no idea why they did this, but I wasted about 5 hours one afternoon trying to ge it to work.. it isn't possible, as the aftermarket models has the valve open while the OEM model has the valve closed.:confused:
 
Thanks Alot Guys !!! Last night while messing around with it, the car would start to die, make the boat horn noise, then the idle would raise back up. Also when shutting it down, A huge rush of air would come out the airbox. Again, Thanks a bunch. After getting everything fixed I went to get gas and there was this fine chick in a LX T-Bird, so I pulled in to the gas station in front of her, and shut the bird down, not knowing it would make that noise, she turned around and asked me if I had a boat horn underneath the hood....Kind of an embaressment, but I got her number :D
 
how do you know

my car idels high too and it made the boat horn sound once thats it i pulled out the idel control valve and put 12 volt to it and it works fine? why do i have a high idel? also i notice a sound like someone was draging blocks of cinderblock or brick across the road the sound came from under me hood and is quite
 
Back
Top