Techs...A mystery just for you!

[aka Larry]

In the category of "Name that noise", here's one that may baffle you. It baffled me, but hey, I'm a AutoCAD operator, not an automotive tech!

Vehicle: 2007 Honda Fit Sport
Engine: 1.5L I-4
Mileage: 120,000

The water pump, serpentine belt, idler pulley, and plugs were changed about 20K miles ago. This engine has a timing chain, not a belt.

The noise heard in the following video only occurs with the A/C running, but not always. Sound doesn't seem to be affected by RPMs. You can't tell from the video, but the noise seems to come from between the exhaust manifold and firewall side.

The following was checked on a lift with the splash shields removed:

- Crank and other pulleys for excessive play - Negative
- Serpentine belt for abnormal wear - Negative
- A/C compressor works fine, no problems at all.

We eventually found the problem, but take a look at the video and tell me what your guess would be.

http://s164.photobucket.com/user/VKZ24/media/20151003_110748_zpsf3qrilbl.mp4.html

 

[domain]

wtf is that

 

[SEV22XS]

Cam or crank sensor would be my guess had ranger that did something similar replaced tensioners belt etc no joy cam sensors where know to go bad bingo no more issues.

 

[aka Larry]

Cam or crank sensor would be my guess...

Incorrect.

Next guess?

 

[Kamn]

sounds like a chipmunk trapped in there

 

[domain]

Something wrapped around clutch plate for ac

 

[saceone]

EASY


that's morse code for BUY MORE TOOLS

 

[koditten]

expansion valve?

 

[MattVette89]

Loose bolt allowing something to shift?

 

[mrolds88]

EGR valve? hard to tell on a video since you really don't have a way to hear what direction its coming from

 

[gahrajmahal]

"only with the AC running" is my clue for a guess. There is a solenoid to increase the idle speed a bit, a relay to draw in the compressor clutch, so something with either of those two things?

 

[aka Larry]

All the previous guesses are wrong. I still don't believe the answer but it's true.

Hint: It was not the A/C compressor or any rotating part.

 

[gayler]

Loose motor mount.

 

[TimeWarpF100]

you said it was not spinning so gotta be a valve or solenoid of sorts. Not that much up on that particular Honda . .

Does that model have adjustable valves?

Never heard a fuel injector quite sound like that . .

 

[steel 35]

Arc jumping?

 

[aka Larry]

Arc jumping?

Getting closer....

 

[1949 caddyman]

I would use a stethoscope to narrow down the area of the noise.

 

[tractordude]

A socket left laying on the engine/engine compartment ?

 

[aka Larry]

A socket left laying on the engine/engine compartment ?

Nope.

Next hint...a part was indeed left loose, but it doesn't rotate.

 

[gungatim]

loose sparkplug?

 

[aka Larry]

loose sparkplug?

DING, DING, DING! We have a winner!

The #1 plug was loose and the chirping sound was from it wiggling inside the hole. Oddly enough it (the sound) only happened with the A/C, and at idle. Increasing the RPMs had no effect on it at all.

When we pulled the COP on the #1 cylinder, the boot was blackened vs. the other three which each looked brand new.

 

[gungatim]

dang...and I didn't even watch the video.

 

[ilovevocs]

dang...and I didn't even watch the video.

Winner winner chicken dinner.

 

[engineer2]

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Lots of useful info and everyone is as friendly as they are here.