I searched and could not find a thread about this. Is it normal for there to be a hissing sound from around the UIM near the IACV when the car is idling?

Or is that definitely the vacuum leak I've been hunting for?

 

hmm, could be a vaccum leak.. Take it off, clean it than either keep and reuse the gasket with some RTV or buy a new gasket. Either way, Clean IACV = Nice clean idle.

 

I don't have an idling problem, and the IACV is clean. I am sorry I double posted this, but am at wits end. I get the P0171 code. The idle is stellar. But something's screwed up because I am running lean. I've sprayed the area with BC, and examined all the hoses. But that has not really told me anything. There is a slight hiss, that seems to be coming from the IACV area, but it isn't anything obvious as far as where it's coming from. Thanks for replying Fallen.

 

dude, no worries.. I would check your exhaust.. Stuff a rag in your Tail pipe and check for leaks before the 02 sensors. Thats VERY important. That or check your intake between the MAF and IM for leaks.. Really man, a Lean code has got to be something thats controlling the A/FR.. and thats either 02 or MAF related. try unplugging your MAF and see if the code remains or if the Car runs worse/better. Could tell you if the leak if there is one is intake related. Also.. Hoses Hoses Hoses!

 

Changed the IACV crush gasket and put some RTV on there. Still read a pending P0171.

There is still the slight hissing sound, which I am beginning to think is normal. It's coming from inside the EVAP valve on the UIM as best I can tell.

 

what is P0171...we're not decoders.


hissing when you rev is normal. There's always vacuum in your engine...that air sound has to come from somewhere

 

The P0171 is a lean bank one code (aka 0115)

I asked the question because the hissing may have been normal, or a vacuum leak causing the CEL above.

It is hissing at idle, as stated in first post. I just wanted to find out whether that's normal. I realize that air has to come from somewhere, but if the hiss on the UIM is where the engine is getting it's air, then that would be the cause of my CEL.

I think that the slight hiss I hear is normal. I need to flag a max owner down, and ask him to pop his hood

 

Take a video. That would be easiest. Did this hissing always exist?

You sure you installed all the vacuum hoses? There's a couple on the mid box.


Put your hand around hoses or seals to see if you can stop the hissing.

 

infowire also has a slight hiss coming from his also and also when the key position is set to ACC, it starts clicking and whirring and ticking and all sorts of ill ****. Mine doesnt do that and his car is running very laggy, is your Max lagging in any way when you accelerate?

 

interesting ive never had this prob before

 

This is another .org member video of a ticking in the IACV, but in it you can also hear the hiss when he moves the camera closer to the IACV. That is the slight hiss I am talking about.

http://www.youtube.com/watch?v=SNIYTLbsVto

I've looked through all of the hoses, to see if touching linkages stops the hiss, also sprayed throttle body cleaner to find out if there's a leak. No go.

Right now I am letting the ECU drive on a new O2 sensor, and it looks like the old sensor was causing the P0171 problem as the car has more juice, and drives faster at lower RPM's. But I won't know for sure until I pass emissions and there are no pending CEL's on the ECU.

I'll update.