Intake Hum Following install
 

So I just finished up installing my MS-1 I purchased from another member here, did the MAF deletion and all that stuff. Now I have this ( for lack of a better term) hum coming from my intake. Its loud enough that is hurts your ears and occurs at idle the loudest but dissipates the hight the RPMs are. I did figure out it is coming from the Idle air control unit and is magnified by the intake pipe ( Old school Rspeed intake). I am running the base map provided on the DIYautotune site until this weekend when I have a chance to actually do a bit of adjusting on the Dyno. had anyone ever experienced this before and is there a fix? BTW its a 1994 1.8 with header, intake and full exhaust. I am running tunerstudio if that matters.

adjust idle stepper motor frequency

I tried that and it didn't seem to help much, I guess I will dick around with it tomorrow when its not so late. Any other ideas?

Make sure your intake hardware is tight and not buzzing against anything.

That was the first thing I check was all the hardware and misc stuff I had fiddled with. I am 100% sure its the IAC valve, I actually pulled it from the intake pipe and the sound became much more bearable ( intake was acting like a megaphone), but the noise is still present.

Some buzzing is normal, I even had that with the stock ECU. To get it as low as possible, you need to run the valve at a frequency of 500Hz, using Jean's PWM multiplier board.

Dimitris

I believe the NA has a slightly lower frequency than the NB, just under 400Hz IIRC.

Got it fixed, kept playing with the frequency utility it went away, now it just idles high. Lol

Dammit, had a smartass response all ready to go when I clicked on the thread and you've already fixed it.

Glad I beat ya to it