hissing on acceleration

[krisP]

Get a hissing when accelerating sounds to be coming from center dash area. any thoughts ?

 

[tjkj2002]

Vacuum leak?

 

[J33Pfan]

snake under the gas pedal lol

 

[J33Pfan]

Get a hissing when accelerating sounds to be coming from center dash area. any thoughts ?

i think there are vacuum lines under the dash to operate heater controls.

 

[LibertyTC]

Both heater/AC mode control switches use engine vacuum to control the mode doors, which are operated by vacuum actuators.
I would refer to the FSM and look even at the vacuum harness and work back form there.
I don't know how accessible this job is going to be.
Get head under passenger side, and see if you can hear leak to get a better idea where or what it might be.

 

[krisP]

still trying to figure this out. only on harder acceleration between 30-45 then goes away. Looked at the decently accessible vacumm lines under parts of the dash and no problems found, same with under the hood. Might need to completely tear apart dash one day if it bothers me enough

 

[LibertyTC]

As longs as the Heater/Ac controls are functioning normally, I wouldn't worry about it.
As you accelerate, the air intake often makes a good suction/hissing sound too...
58825[/ATTACH]"]

You must be registered for see images attach

I remember once wondering what the heck this sound was, also believing it may be a vacuum problem.

 

[uss2defiant]

there's a hissing sound from the air going through the TB.
Can you try to see whether it's the same sound with the hood open and you pushing on the throttle lever?

 

[krisP]

yeah those may be it and ive just never noticed until now...my pcv valve is located closer (like a KK) so i was thinking maybe that was loose but no codes and doesnt run any different. Ill just let it go for now and try and track it down in my spare time

 

[JeepinJarhead03]

i couldnt hear mine do it until i fixed my power steering pump, between 3-4k there's a harmonic, like a straw vibrating when you squeeze the end almost shut

havent figured out exactly what it is, have some remote mic's i can use to chase it just haven't gotten around to it, almost 100% sure i dont have any vac leaks, im ocd about that sort of stuff but at the same time, doesn't mean i dont either

if messing with the heater/ac director knob changes whether you hear the hiss or not itll help determine which of the vac lines behind the knob may be loose, mine will stick halfway to the floor position until i rev it up slightly to increase the vac and then itll close up

 

[renegade 04]

The intake is loud, and if you remove the little riveted in air dam in front of the air box you will hear how loud the intake can be. When I start my jeep I can hear the intake sometimes 30 feet away.