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3,047 Posts
Discussion Starter · #1 ·
I hear a sound between 4500-5500rpms (where the max torque is of the turbo and the SR20 in general) that sounds like one of those cheap plastic annoying horns you blow at kid's birthday parties and on New Years. At first I thought I had a small hole in my boost gauge line since it sounded like it was coming from the harness firewall throughway area. Well I have my boost gauge disconnected right now and I still hear the sound. From the driver's seat it sounds like its coming somewhere like the passenger footwell, glove box, or the door jamb. Mike Jez said the AAC and/or IAC valve is over on that side of the engine bay and it could be leaking under boost. That sound plausible? Any other ideas anyone has? I can hear it lightly under any boost and is very loud under full boost between those rpms. I had my windows down once last night and I could hear the noise echo off the fences and houses around me. Ideas?

3,047 Posts
Discussion Starter · #3 ·
Close off which hose? The big fat one or the small solenoid one? Is that what yours sounded like?

3,047 Posts
Discussion Starter · #5 ·
Well I did something better tonight. My buddy with a 90 Eclipse Turbo was working tonight, and he's really cool, so he let me borrow his BOV for a moment. Freezing ass cold with 30mph wind gusts I was doing this. Went for a drive and it made the same sound. So it ain't the BOV. Going now to search for the real leak. Wish me luck

3,047 Posts
Discussion Starter · #6 ·
Well it ain't the T's because I disconnected my boost gauge which enabled me to remove one T and connect all vital stuff up, and then same thing with the other T. Still makes the party horn noise. I broke one of the T's AGAIN so tomorrow I am getting brass ones and being done with it.

I need an air compressor so I can use it as a pressure tester as suggested by two folks on the SE-R list.

From Jay Stewart:
"Ben, make a pressure tester like this, and pressurize the system.

Go here:

Click on the "pressure tester" link on the left.

On every single car that wasn't turbo that I have worked on, there are
*always* some crazy leaks everywhere. It just wasn't designed for positive
manifold pressure.

This is *the* most valuable tool for turbo troubleshooting (besides gauges).
I have fixed sooo many cars with this $5 tool that it isn't even funny.
*Every single car* that I hook up has leaks, no matter how much the owner
thinks he has checked all of his connections.

Also, be careful with cheap plastic T's, my friend lost an engine to one of
those. Turns out the flashing was blocking one of the ports, the one that
fed pressure to the fuel pressure regulator. I suggest (and only use
myself) higher quality metal T's. Also, you should zip tie all of your
vacuum hoses, and probably replace them all with silicone hoses as well. You
do NOT want to lose an engine over something stupid like a hose that pops

(nearing completion of his 6 month long engine rebuild saga, about to start

Jay Hassinger had the same thing to say:
"Make a fitting to go onto the compressor inlet that has an air chuck,
pressurize the system and if you have leaks they will show up loud and

It's really easy to do. Go to Home Depot and get some sort of cap that
matches the size of your compressor inlet, then get a threaded nipple for
air tools. Drill a small hole in the rubber cap, stick the nipple through,
use a nut and washer on the inside to hold it in. Hook up your air hose
and regulate the air pressure to 15psi or whatever you want and voila.

Jay Hassinger
B14 Turbo."

and then Mike Jez said:

"I think it might be some of the emissions crap on top of the manifold. Under
boost it might be leaking from those hoses on top of the manifold. I would
check em out. Also check the IAC and the AAC valve, they might be leaking."

That could be the cade, but those are still "frozen" if you will to where they are connected to from the factory. Never moved them so you would thing they would be tighter. should I clamp down one of them at a time and see if that fixes it? Will that hurt anything to close several of those off?

And since I have the EGR system "removed" would it be ok to clamp the hoses on those too and check?

Jay Whitley was the only person to suggest removing my PCV valve and use a slightly different method:
"You definitely have something leaking....that is for
sure. Here is what I did to diagnose my leak and I
guarantee you that it will work! First, disconnect
the hose to the PCV valve on the valve cover and seal
it up or cap it off with a rubber vacuum cap from Pep
Boys. Next, disconnect the oil vapor return line from
the valve cover to the intake hose. Cap off the
connection at the intake hose where this hose
connected. Then, remove your air filter and MAF
sensor and seal it up with many pieces of duct tape.
After that, wrap the duct tape with plastic wrap and
secure it with 2 or 3 zip ties connected together.
Rotate your motor to TDC so that all the valves are
closed. At this point, you will need to go to Pep
Boys and buy a portable electric air compressor. It
will come with fittings so that you can connect a
rubber hose to the end of it. You will need to
connect the air compressor to a hose leading to the
intake manifold, such as the brake booster, fuel
pressure reg vacuum line, PCV hose, etc....Just make
sure to open the throttle when you turn the compressor
on. Turn on the compressor for a few seconds. The
plastic wrap on the end of your intake hose probably
start to expand slightly, but it will not pop b/c the
air is being let out slowly from wherever your leak is
located. Turn the compressor off and then listen for
a hissing noise. If there is a leak, you will
definitely hear the leak and you can easily pinpoint
your problem. After you have found you leak, wrap up
the compressor and return it to Pep Boys (if it is not
against your morals). You do not want to use a high
pressure source. So, be sure not to use a lot of
pressure, as you may have access to air tools and
hence, a "real" air compressor. Please make sure to
disconnect all connections to the valve cover.
Otherwise, the pressure will blow out the gasket
material in your timing chain cover and you will have
another hard to reach leak!

Good luck,
Jay Whitely

Call me if you have any further questions."

Well I ain't got an air compressor. Asking for one for Christmas though.
I am thinking to start with just start clamping emissions hoses and see if it stops making the noise. If it's not a simple hose leaking and it's actually some piece of emissions equipment, then what?

Well I did fix the rattle in the back that was from the motor mounts. One of the 4 push pins in the headliner in the back was 1 notch loose. Pushed on it and it snapped in 1 more notch and the rattle was gone.
Nissan build quality...

3,455 Posts
check walmart for the CH gift pack
it may just be at this store here i dont know. it comes with a decent compressor, and like every immaginable tool for like 250 IIRC i want it so bad. may see if they still have them next semester if i have excess aid again i will get me them

3,047 Posts
Discussion Starter · #8 ·
Figured out what the sound is. On my downpipe from the turbo to the cat there is a pinhole opening in the cat-end flange weld where you can just see light through. I was going to JBWeld that before the turbo went on, but I forgot. When I went to dinner with Wendy tonight I found that I could make the sound by free revving it. So I was like "cool, I can sit and find the leak now." so I popped my hood and free revved it. Couldn't hear the noise at all. so got in the passenger seat and free revved it keeping the door open. It was coming from under the car. that's when I realized what it was. Will fix that tomorrow. That will give me an excuse to run exhaustless for a day

3,047 Posts
Discussion Starter · #9 ·
Sounds much better now. About 85% better with my crappy JBWelding job. Easily livable. It makes NO sound outside of the top 1000rpm of the torque band. When it does make sound, it's almost nothing. Easily livable until I get a 3" downpipe made in a few months
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