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Weird Buzzing noise

trouthunter

Full Member
Joined
Apr 8, 2003
Messages
226
Location
Tacoma, WA
OK, I'm getting this weird noise intermittently. It's most obvious when I'm in the parking garage at work going between floors, so the nose is pointed up and I'm giving it gas and turning right to go up the ramps (not so much when I'm leaving, going down, right and no gas), but I get it in my driveway as well as other places, so it's not limited to just that angle.

It sounds like a vibration or a pump straining. Just a humming buz kind of sound. It's hard to tell exactly where its coming from but it sounds like it's behind me and maybe to the right.

Any ideas? Of course this happens 5000 piles out of warranty. :rolleyes:
 
I would say it is the fuel pump. When going up hill the fuel pump is more uncovered by fuel than when going down hill. The more fuel in the tank the quieter the pump. Fuel pump is located towards the front part of the fuel tank. This is usually normal for GM fuel pumps. The only bad thing is when they go they go and no warning.
 
I thought that, too, but it doesn't seem to matter how much fuel is in the tank, and it happens on flat pavement as well
 
I get a noise too; it sounds like a vacuum pump or a small compressor starting then stopping. It's not loud but loud enough to wonder what the hell it is. It's usually after I start up and drive easy from cold. Then that cycling stops after a few minutes until the next cold startup.

More common in high altitudes.
 
[flash=200,200][/flash] I had same thing. It was the speaker above the drivers head. I don't have the on star but the speaker is there. Was aggravating as 43LL, took it to dealer they fixed it. Can't remember what they said it was. I'll look it up tomorrow morning.
 
OK, I found it. I just don't know exactly how to fix it. The exhaust is still stock, and there is a plate that sits between the muffler and the body of the truck, directly below the passenger side back seat. I'm not sure what its purpose is - maybe a heat shield or something. At any rate, that thing is vibrating like crazy. In fact, if you hit the back seat there with your hand, you can set it off like a tuning fork. I found in when I was cleaning under there and I had the seat up to vacuum. I dropped it back into place and hummmmmmmbuzzzzzzz.

You can stick your hand up between the muffler and the body and feel it, but I haven't the faintest idea what to do to make it stop. Granted, we were getting some rain and I din't crawl around under there too much, so I haven't really had a good look at how it is attached, but I suspect the muffler is going to be seriously in the way.

Nuts. Well, now that I think about it, this might not be a bad time for a muffler swap, lol...
 
Its the heat shield. Take it to your dealer it is tack welded up to the floor. The tack weld probably broke it should be fixed by the dealer (y)
 
Holy cow - three whole minutes to get an answer - you guys are slipping >:D

Thanks bonedog! You guys are awesome. That sounds like something the dealer might charge me for, since it is out of warranty.

Which brings up my next question - since they are already up under there, welding right in the vicinity of the muffler...Magnaflow? Flowmaster 50? I know we are talking about marginal performance gains, so what gives me the most bang for my buck, keeping in mind that I consider sound to be a performance gain (lol - kidding, but I do want it to sound good)
 
trout in the immortal words... Do A Search there have to be a million threads on the mufflers. I myself am changing over to Magnaflow after my flowmaster setup. I will not get into the reasons here though.

Give a local muffler shop a call and maybe for a little tip 10 bucks they can hit the shield with a tack weld. We are talking a 5 second job. Hit the factory spot welds again. The dealer might be able to only beacuse it is part of the exaust system and exaust systems are warentied I think 5year 50K by the government...at least on the cats they are. Give it a try remember a phone call costs nothing.

If you do go aftermarket exaust just get what you like. Magnaflow sounds good..little reasonation FM70 setup from muffman.. the list goes on and on.
 
Mine's not that; it's something switching on & off - electrical.

Good find anyway!

 
Yep! Kinda like a purge pump or some smog gadget. It just does it a few times then settles down.

(Sounds like a low-volume "Ah-ooh-gah" horn.)
 
what is the build date on your 03?? You might have the hydraboost system inside yours. It could be the vacum pump for it building break pressure. Once the pressure is up then it no longer cycles until needed. IE extreme breaking situation.

OR

Might be your ABS system. Mom's EXT does this occasionally... why?? No clue... sounds almost like an airbrush compressor turning on for like 2 seconds then off then on again. Faint but still audible to persons that know their vehicle.

If it is either one I would say you are intune with your vehicle in a heightened state and all is normal. Both things make the noise you described and both do it from day one.

FYI I belive the Hydraboost started showing up on 03's around mid year... 04-06 months. I believe not 100% sure though.
 
Good tips, thanx!

That on/off for a few seconds sounds like it.

It won't do it if I back out of the garage or pull in after starting it. It will at my brother's place (5600Ft.).
 
bonedog said:
trout in the immortal words... Do A Search there have to be a million threads on the mufflers. I myself am changing over to Magnaflow after my flowmaster setup. I will not get into the reasons here though.

Give a local muffler shop a call and maybe for a little tip 10 bucks they can hit the shield with a tack weld. We are talking a 5 second job. Hit the factory spot welds again. The dealer might be able to only beacuse it is part of the exaust system and exaust systems are warentied I think 5year 50K by the government...at least on the cats they are. Give it a try remember a phone call costs nothing.

If you do go aftermarket exaust just get what you like. Magnaflow sounds good..little reasonation FM70 setup from muffman.. the list goes on and on.

lol - I know, I know... We were already in here talking about welding around the muffler, so I figured what the heck. I have already decided on the Magnaflow.
 
ok sounds silly but...

when i start my AV up the microphono above my head in the roof liner for the ON STAR vibrates. I know its this because if you touch it the noice stops. Its a really irating buzzing noise as well..

 
That's not the OnStar microphone. It's the ambiemt temperature sensor for your auto climate control. There is a small fan in there that's making the noise.

HTH
 
well i didnt know that! ok that explains what i though was another microphone nearer the front :)

well maybe thats his buzzing noise.
 
Here's the OnStar mic.

clse102.jpg
 
    I had the same sound that you describe, and thought it was the motor in the seat. Turns out, took to dealer and had the climate control motor (overhead looks like  a speaker) replaced. let me know if that is it, k???? ;) ;D
 
trouthunter said:
OK, I found it.  I just don't know exactly how to fix it.  The exhaust is still stock, and there is a plate that sits between the muffler and the body of the truck, directly below the passenger side back seat.  I'm not sure what its purpose is - maybe a heat shield or something.  At any rate, that thing is vibrating like crazy.  In fact, if you hit the back seat there with your hand, you can set it off like a tuning fork.  I found in when I was cleaning under there and I had the seat up to vacuum.  I dropped it back into place and hummmmmmmbuzzzzzzz.

You can stick your hand up between the muffler and the body and feel it, but I haven't the faintest idea what to do to make it stop.  Granted, we were getting some rain and I din't crawl around under there too much, so I haven't really had a good look at how it is attached, but I suspect the muffler is going to be seriously in the way.

Nuts.  Well, now that I think about it, this might not be a bad time for a muffler swap, lol...

Thanks Trouthunter, I'll be looking into this tomorrow.....started hearing the exact noise you describe this evening...... almost sounds like a vacuum pump or light brake rub..... I was going to check the brakes as I just put the new EHT pads on a few days ago but now I'll look there before pulling wheels.
Thanks
 
:E: Well, that wasn't it.... nothing was wrong at exhaust, or anything visible out of whack under the truck but still getting the noise intermittently.... sounds like a brake pad rubbing just ever so slightly but only seems to do it on an incline when turning under slight throttle.
 
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