Harmonics coming from intake!!

[jwild4x4]

I had installed a K&M FIPK about a 10 months ago. Recently I noticed a very obvious and high pitched humming sound (sounds like blowing over a beer bottle, but a little higher pitched) comming from under my hood durring idleing. It goes away once I put it in first and started to give it gas. (I have a manual tranny). After a while I got so annoyed, I thought it must be the FIPK, so I removed the filter unit, and to my dismay the humming continued. I tried changing the way air flew into the intake tube with my hand, but to no avail. It sounds as if it's coming from deep inside the tube and is not caused by the FIPK. If anyone has any suggestions... I am completly baffled! I'm worried that if I take it to Ford and tell them my intake is making harmonics, they're just going to tell me it's the FIPK. Sure could use some help. Thanks.

Jason

 

[Lifted95X]

Sounds like another case of a dirty/bad IAC valve. I have the exact same problem with my explorer...and from what i have read on this board....I think the Idle Air Contorl valve is the culprit.

 

[jwild4x4]

Yes, but if the IAC valve was bad, wouldn't the engine have an unstable idle. ie: fluctuation or stalling? It's interesting... If I rev my engine, I can still sort of hear the harmonics, yet once I release the clutch, and the clutch starts to bite, the sound instantly goes away. Any other suggestions?

 

[Lifted95X]

the sound goes away even at very low rpmwith the clutch engaged???

 

[jwild4x4]

Well, yeah... I can hear the sound start to fade slightly even if I put it in 1st and begin to release the clutch without giving it gas. But like I said, I'm positive it's coming from the intake (near the manifold) I read your post and went to my shop manual to find the IAC. The one pictured in my manual has two screws which secure the valve to the mounting bracket, which is mounted to the manifold by two bolts. I have a 95, V6, 4.0L, and what appears to be my IAC does not have the two screws which will allow me to remove the IAC valve. I would love to fix my harmonics problem, and would like to know how to remove the IAC valve to check and clean it... Thanks

 

[Lifted95X]

I have a 95 also...and it should have two bolts to remove it....it is located just on the intake past the throttle body....it has a little black button looking thing on it....look again and make sure your looking at the right thing.

 

[jwild4x4]

Yeah, that sounds like it. I could have sworn that was it. The older models have screws to remove the actual motor/valve from the mounting bracket. But the pictures look the same.

It seems that mostly people that have modified their airbox/filter unit are having these problems... Is it too much dirt/dust getting through and gumming up the valve. That really can't be good inside the pistion I've read lots of threads on that subject, and contacted K&N. it seems as if they think it's not an issue. hmmmm

Thanks for the help SSIKORA. Sorry to all that I didn't search the threads better before asking this question. It just seemed so unique. I didn't expect a slew of people to have had the same problem. thanks for your help anyway! This form rocks! I let you know the outcome....

Jason

 

[jwild4x4]

Well, I tried cleaning the IAC out with some carb cleaner and some compressed air. Unfortunately, the second time I drove it, the sound came back! It fluctuated at first, which it has never done, so I'm pretty sure that the valve is to blame. I emailed ford parts network and they quoted me $ 97.99 for it! Everywhere I've called has wanted more for one, so I think it's a good price... What do you think?

 

[Lifted95X]

I just called Murrays Auto parts by me and they said it was 80.89.

 

[o6tnineo]

hey jwild, does yours only hum when it is over 90 degrees outside???, cuz i think that's my problem too, idle is really loud, but put any small amount of load on it and it quiets back to normal.


That means i can get it fixed this weekend.