Alright, so I just finished an intake manifold swap, and now I have a low pitch gurgling or bubbling sound coming from the firewall/pedal area. I can hear it from inside the car, around the driver front tire and under the hood around the brake booster. It increases with RPMs and is most noticed at idle/low rpms... I didn't notice this noise till after the manifold swap, and am worried if this could be a sign of something wrong elsewhere..

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Update
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Since this has started about a week ago the noise has gotten louder..

The brakes still function properly, I have lower oil pressure at idle than what I'd like at idle (10-12psi), while at 1000+ rpms it goes 30-45 easily, and this is with brand new oil/filter.

Any ideas? I really hope this isn't a sign of something really wrong.

http://s58.photobucket.com/albums/g2...WeirdNoise.mp4

 

Anyone have any ideas at all?

I'm stumped... I've never heard a noise like this one before.

 

bump..

 

Could it have something to do with your brake booster?

 

I don't know for sure....

That's the only thing I can think of it coming from around that area... It's getting really loud and annoying.

As far as my oil pressure goes I think it's a faulty sensor/sending unit... today it's acting the same but now idles at 30 psi

 

You should get a new ops unit and talk to the boys at the parts store. Tell them you need something you can spray around looking for a vacuum leak. When the spray like brake clean hits a vacuum leak the engine will speed up.

 

You mean like to check for a vacuum leak?

 

Yes sir that was what I thought you might try.

 

I'll spray some carb cleaner around there when I get the chance and I'll see what happens...

It just doesn't sound like a vacuum leak, no sucking/whistling noise... just that hollow plastic thumping sound....

 

For some reason it sounds like the AIR pump. That fluttering/gurgling intake sound.

The AIR pump is on the passenger side, but maybe the intake for it faces the drivers side.

Unplug the solenoid connectors for the AIR pump and see if the noise goes away.

RBob.

P.S. with my luck this car already has an AIR pump delete in place...

 

You mean the Smog pump?

If that's what we're talking about, then yes, it's already been removed from the car

UPDATE:

Today I took a long, thin metal rod and started poking around the engine with it with my ear pressed on it while i was doing it, to act like a stethoscope more or less..

So I started poking everything, nothing out of the ordinary... Injectors pulsing, alternator whining etc... Then I poked under the TPI and then...

BAM!! I found it! I touched my Adjustable Fuel Pressure Regulator and that rod started going nuts! The exact tone, rhythm, everything.... This is where the noise is coming from...

What the heck is going on here?

 

Your Adjustable Fuel Pressure Regulator is, well, regulating fuel PSI..

 

Wonderful job trouble shooting, thanks for letting us know what it was.

 

I guess now the only thing I can do is swap it out for the stock one.....

Crap
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Fixed it

Swapped out my TPI Parts Adjustable fuel pressure regulator out and put the stock one back on.... Now my car doesn't sound like a diesel from inside the car.

Still don't know what would have been causing the thumping though, considering the only movable part in the AFPR is the cap that compresses the spring?