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Old 04-05-2011, 05:50 PM   #1
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Default Farty noise from exhaust

The car is making a farty sound from the exhaust. I don't mean Honduuuh farty, its almost metalic. Imagine sticking your toung out and making a fart noise.

It is load dependent, and happens at all RPMs. I can expecially hear it when the sound is bouncing off a wall coming back at me.

Specs:
1996, stock 1.8
2560, 3" turboback (strait pipe with a 16" long 4" diameter can, no cat)
DIYMS-I

I don't know if I am imagining it, but the car seems slower. I'm thinking I might have slipped a notch on the timing belt, but that's just an early guess.

Thanks

EDIT: It almost sounds like an exhaust leak but its coming from the tailpipe.
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Old 04-05-2011, 05:51 PM   #2
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sounds like a misfire from description
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Old 04-05-2011, 05:54 PM   #3
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I forgot to note that the sound isn't there at idle... at least not loud enough to hear. Thanks for the idea though, I'll throw a timing light on there.
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Old 04-05-2011, 05:55 PM   #4
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Happens at all RPMs and loads? What is your plug gap?
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Old 04-05-2011, 05:57 PM   #5
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Forgot, but they have been gapped. And the car has been fine up until now.
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Old 04-05-2011, 06:01 PM   #6
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Sounds to me like you have a weak or dead cylinder. Try running the car for a minute and spray a little water on each exhaust header pipe. If one does not sizzle or sizzles less than the others, you have found the problem cylinder.
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Old 04-05-2011, 06:32 PM   #7
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Don't think its 3 cyls, it idles fine
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Old 04-05-2011, 06:39 PM   #8
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Quote:
Originally Posted by rider384 View Post
Don't think its 3 cyls, it idles fine
So did mine, but it had a cracked piston, and made the same farty noise. Got the same farty noise when I had a weakly firing cylinder also.

Stop second guessing and see if you lost a cylinder somehow.

Edit: Mine also idled normal with both occurances. Noise began when under a load.
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Old 04-05-2011, 07:06 PM   #9
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Bring it by and lemme have a hear at it :P
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Old 04-05-2011, 07:32 PM   #10
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I'm thinking its a spark plug, smells heavily of gass
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Old 04-05-2011, 07:34 PM   #11
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Der, you going to boost for boobies?
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Old 04-05-2011, 10:20 PM   #12
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Confirmed that all cylinders are indeed firing.
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Old 04-05-2011, 10:45 PM   #13
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how rich is it? they sound like that when they get pig rich.
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Old 04-05-2011, 10:48 PM   #14
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Just checked, about 17:1 at idle, like it's always been.

I'm starting to fear the worst here, guys. I will be getting a compression test to determine if I burned a piston or something.
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Old 04-05-2011, 11:11 PM   #15
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i mean when it farts. and thats way too lean at idle.
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Old 04-05-2011, 11:14 PM   #16
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Thanks, I will richen it up.

AFRs are ~ 14 when it's revved up slightly and the farting occurs. AFRs are fine under boost as well...
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Old 04-06-2011, 09:31 AM   #17
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I reread your description and it makes me think exhaust leak.
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Old 04-06-2011, 10:39 AM   #18
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Cars for boobies?! Haven't heard of this'n. I am getting a quote for exhaust tomorrow and maybe getting it done shortly after. When is this thing happening?

Also, I have a leakdown tester but it might be bad, I got a popping sound while using it last time and I'm thinking the hose is bad. We can always turn the compressor reguator to 15psi and plug the line in and listen for sound :P
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Old 04-06-2011, 12:44 PM   #19
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Compression check today. Will post the results when I get them.

If there's no compression on a cylinder, I assume that it's either a cracked/melted piston or could it be a burned valve or something?

Der, it's on the 16th?? Something like that. Or the 22nd. I don't remember. Check it out on facebook, just search boost for boobies and it will come up. It's a charity event held by MAP for Race for the Cure. Dyno spots will be auctioned off at 9:45am and some time in the afternoon...

Hopefully this will be fixed by the 16th, but I fear the worst.

EDIT: So, if my compression is low in 1 cyl, it means that there's a problem with the rings or something. If the compression is just not there, it means that there's a problem like a valve or burned piston. Correct?

Assuming the compression is good, what could it be? My friend said the turbo, but I'm thinking it's too in time to be a rattling compressor or something. All cylinders are firing. Started it cold this morning to move it and the sound was pretty bad. MUCH more noticeable then when it was warm. This leads me to believe that it's probably a ring or piston slap or something along those lines.

Last edited by rider384; 04-06-2011 at 12:57 PM.
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Old 04-06-2011, 12:59 PM   #20
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Can't make that, I work weekends. Good luck.

Oh and if it's the block or what not, I have a bottom end that's just sitting around (head is being pulled).
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