Help me find the hissing noise

[Vtolds]

I replaced my exhaust yesterday because the stock one had a whole in the muffler. Before I had a noticeable hissing noise that I figured was the hole in the muffler. After replacing the muffler and determining I have no leaks the hissing sound is still present.

http://s2.photobucket.com/albums/y2/Vtolds/?action=view&current=JeepExhaust.mp4

What could it be? The sound does disappear when I hit the gas, I am thinking it could be something fuel pump related but I dont have the skill to determine that for sure.

 

[LibertyFever]

I'm going to hazard a guess that's typical but that you couldn't hear it before because of the hole in the muffler.

 

[Ry' N Jen]

Sounds to me like you have a vacuum leak under the hood somewhere!

 

[mag03kj]

K
I had the same sound. I had 2 diff. places it was doing it tho!

1) It was on the driver side on the firewall. Hose was cracked!
2) It was a fuel line under the drive door! Hose was cracked!

Replaced both and the noise stopped!

 

[ptsb5a]

K
I had the same sound. I had 2 diff. places it was doing it tho!

1) It was on the driver side on the firewall. Hose was cracked!
2) It was a fuel line under the drive door! Hose was cracked!

Replaced both and the noise stopped!

Fuel lines don't hiss dude, they piss fuel out everywhere. Sure it was a fuel line and not a vapour recovery something or other?

 

[mag03kj]

Fuel lines don't hiss dude, they piss fuel out everywhere. Sure it was a fuel line and not a vapour recovery something or other?

Ok...yes now that you say that.....Thats what it was a vapour recovery! Its still part of the fuel system!

 

[osufans]

x2 on the vacuum leak. Especially since it goes away when you press the gas.

Check your vacuum lines in the general area you hear the hissing.

 

[kjweston]

The hoses coming out of my valves?? I think thats what they are, are both cracked.. the ones that connect to the sides of the airbox. Would this cause a hissing noise? It was pretty bad before so I replaced some pulleys and the belt and it got a little quieter.. but not totally gone. Now its bad again. Granted I do have a ram air on right now but I dont think it should hiss as loud as it does.. btw sorry to slightly thread jack.. but similar problem.

 

[Vtolds]

I know for certain it is not coming out from under my hood it is in the back of my car. It is not my exhaust. I changed my exhaust because I thought it was and the sound never changed. The suggestion of the vacuum leak makes sense. Which lines should I be looking at? I dont think I will know a vacuum line from any other kinds of lines. So if someone can grab picture of the locations to checks, and what I would need to fix them that would be very helpful.

 

[mag03kj]

It could be want i said!
Jack the damn KJ up and just start the jeep and start looking!

 

[Vtolds]

Any body?

 

[ThunderbirdJunkie]

I know for certain it is not coming out from under my hood it is in the back of my car. It is not my exhaust. I changed my exhaust because I thought it was and the sound never changed. The suggestion of the vacuum leak makes sense. Which lines should I be looking at? I dont think I will know a vacuum line from any other kinds of lines. So if someone can grab picture of the locations to checks, and what I would need to fix them that would be very helpful.

*sigh*

Check the evap hoses in front of the gas tank above the rear axle.

It's not that hard to pinpoint in most cases.

 

[Ry' N Jen]

Go to Harbour Freight and buy yourself a Mechanics stethoscope.
http://www.harborfreight.com/automotive-motorcycle/diagnostics/mechanics-stethoscope-41966.html
They work wonders for finding such little annoying leaks!
Then go over every hose related to vacuum!
ie. Cruise control servo(Vacuum reservoir), Power brake booster, HVAC system,
Emission control system. Check out everything around the intake manifold as well.
Also check the exhaust manifolds.

Either that or take it to a dealership and have them diagnose the problem!

 

[Vtolds]

Found it. Quick fix, I used electric tape. nana.gif I dont know if that is a good way to fix it, but its working.

 

[ThunderbirdJunkie]

Electrical tape doesn't fix ANYTHING. Just replace the bloody hose dude. It's like 50 cents a foot.

 

[Vtolds]

Electrical tape doesn't fix ANYTHING. Just replace the bloody hose dude. It's like 50 cents a foot.

How does sealing the whole with rubber tape, any worse than replacing it with a cheap rubber hose? Stopped the leak = fixed \\/

 

[ThunderbirdJunkie]

it didn't stop the leak, but keep on keepin' on brother man.

 

[kjweston]

How does sealing the whole with rubber tape, any worse than replacing it with a cheap rubber hose? Stopped the leak = fixed \\/

C'mon man!! gotta use rubber tape and reinforce it with duck tape.. duhhhh
no I'd replace the hose.. the tape will begin to leak in a week or two.. I did the same thing on a hose into my EVAP canister.

 

[mag03kj]

Ya i would just go get like 50cent of hose and replace it!

 

[osufans]

was this the EVAP line? TBJ, what kind of hose are you referring to, just vacuum line?

glad to hear you found the cause.