I changed out my iac valve because the check engine light told me to. But it still has the same problem. It makes a weird fish tank noise. What else could it be? I don't think its the wiring because when I disconnect the iacv. It acts different. So im confused. I have a 97 civic ex. D16y8

 

weird fish tank noise? and just cause it it makes a difference unplugged doesnt mean its not wiring, have you tried reseting the ecu? does it idle funny?

 

What was the engine code? Did you bleed the coolant after replacing?

 

Ok so I drove it around today for a bit and yeah the weird fish tank noise is still there. Hard to describe. Anyways I took out a fuse to reset the check engine light. And it hasn't come since. Which is a little different because usually it comes on very soon. Anyways how do you reset the ecu? I also did bleed the radiator fluid. Made sure it had the right amount and did the bleeding process.

 

There's no code that tells you to replace the IACV.

What code was thrown just before you reset the ECU?

Post a video with sound to share the fish tank noise. Where is the noise coming from in the engine bay?

 

It was a p0505 code. The dude said thats what it was. And according to that code chart on this website that some dude made. Thats what it was. I'll record it for you. It's coming from the engine. Somewhere by the intake manifold

 

Don't believe everything you read on the internet. A bad IACV is only one of several different possible causes for P0505 - others include the idle speed needs adjustment, a vacuum leak, and a problem in the ECT sensor or TPS circuit.

Figure out exactly where the noise is coming from and post a picture.

 

It looks like its coming from where the intake/manifold is at. First off i hear a high pitched constant noise from the intake. And the second noise which cuts off and on frequently is that noise I described. I hear it on lower idles like when Im at a stop. It's sometimes louder than other times. I notice when I turn on my lights or use my automatic windows it comes on.

 

Get some carb cleaner. Spray around the intake manifold, throttle body and vacuum lines. If the idles raises at any point that is where a possible leak is.

 

do i have to unbolt the intake manifold?

 

nope, just have it running n spray around all the lines n u should notice a change if there is a leak.

 

Ok. But like where are the vacuum lines and stuff

 

lol^ just spray all the hoses going to your intake manifold....

 

So I sprayed all over the intake manifold and the hoses around it and still nothing. I didn't see an idle drop. Could it be because I installed an eBay short ram intake? I installed it like 4 years ago. I notice it makes a high pitched sound.

 

Ok, I decided to take my after market short ram intake and installed my stock air intake WITHOUT the resonator. Still has the same problem but at a lower sound.

 

Bump

 

So here is the video. sorry for taking long on it. i only got the weekends to do anything. lol

 

vacum leak

 

Bump

 

I'd say adjust your fast idle valve, clean your throttle body/intake and check for vacuum leaks.

 

how do i adjust that?

 

I thought the Y8 or any post 96 civic didn't have a FITV (fast idle valve)?

What is the easiest method to test for a leaking Intake Manifold, or a leaking Throttle Body?

When OP said fish tank sound my initial thought was vacuum leak, but I usually think hoses. Not sure how to pin point gasket vacuum leaks.

 

You'd be correct. Also using carb/tb cleaner sprayed around vacuum line and gasket areas and listening for idle changes is a proven method for finding leaks if you don't have access to smoke testing.

 

Another thought occurred to me when I was in the shower this morning.... I recall seeing gunk buildup in the intake runners on the engine that was pulled from my car. I know some gunk can come through the pcv valve, not sure where the rest of the blackness comes from.

Anyways, is it possible for the gunk to build up enough in one of the runners to cause a sort of whistling affect at certain air flows/throttle positions?