Whistle at idle/ocassional surging

[281pony]

i did the 25 point surge checklist deal before. i got clear down to finding out my alternator was fried. i just replaced it with a new 95 mustang 130 amp from cut rate. idle problem went away.

in the process of trying to fix the surging then, i had tinkered with tps adjustments and cleaning iac, cleaning maf, clocking maf, fuel filter, cleaning sensors, ect.

so it idle'd pretty high with the alt in there. i also developed a hanging idle. i read and came to the conclusion i'd set tps voltage, disconnect battery, then turn back idle screw and set it from there.

i did this, got it idling, set it at 750 to start, ended up moving from 800ish to 1000 rpm idle via my saleen cluster. so im guessing 950ish rpm with a trickflow stage 1.

idled GOOD. returned back down to rpm pretty well, it would ocassionally drop from 950 rpm to about 750 real quick then stabilize at 950 right after. i let that slide, took it around the block, and it was fine. then came the horrid whistling again. i looked for leaks, ect. nothing.

here is a video; YouTube - MVI 1931

after this whistle started, the car also surged when i pulled back into the driveway. i put it in neutral and revved it. it would no longer return to idle, it dropped to 500 rpm, surged to 1400ish about 3 times and died.

before the surging, when it was only whistling, i unplugged the iac and nothing changed... wtf is this?

 

[281pony]

i do have a bbk tb, is that the notorious whistle? its that loud? the egr plate has been deleted as well.

if so, is this surging issue common with them too? its going in the garbage if that is the entire issue.

 

[1991notchbackLX]

i do have a bbk tb, is that the notorious whistle? its that loud? the egr plate has been deleted as well.

if so, is this surging issue common with them too? its going in the garbage if that is the entire issue.

YES! my BBK 70mm throttle body whistles like a God damn freight train at idle. I also get stumbling/surging idle, but only when it's very cold out. I've read on a few forums about drilling a tiny hole in the throttle butterfly plate and that will eliminate the whistle, but I wouldn't recommend it, personally.

 

[281pony]

ok. i drove it to eat tonight, about 15 miles round trip. it seemed to calm down pretty good on the idle. still whistled off and on, so ill just plan to snag a different throttle body i guess.

thanks

 

[1991notchbackLX]

I deal with the throttle body whistle because my car performs and idles very well despite it. I also like when idiots in Nissans ask if it's supercharged because of it.

 

[rednotch88]

I heard you polish the IAC passages to lose the whistle.I myself don't mind the whistle its just plays another role in the cars character.

 

[1992MustangGT]

I was reading some trouble shooting info about this exact problem you're having (whistle and bad idle and surging) and it stated that it was a bad IAC. I would replace the IAC before replacing the TB. Might just solve your problem....

 

[Chuckman]

I was reading some trouble shooting info about this exact problem you're having (whistle and bad idle and surging) and it stated that it was a bad IAC. I would replace the IAC before replacing the TB. Might just solve your problem....

its the tb itself that actually whistles, and i think its the iac ports that are to blame. i had the same problems when mine was running, and i never had this problem when running the factory tb.