Need help with tapping sound diagnosis (vid)

[Wade T]

Had the car(90T) about 2 years w/ 172k miles and it's mostly stock minus some HKS exhaust mods. About 4 months ago i noticed a tapping sound at light loads. It happens when letting off the gas or driving down hill not using compression. It also happens when the slippy auto trans won't shift right away.

In the vid i had to really work the throttle to find it.
http://www.youtube.com/watch?v=dAkL_VujPeo

 

[SrBigbutt]

Kinda sounds like what my Torque converter sounded like before it really started making noise. But at first it would only do it when taking off from a stop.

 

[88_7mge]

Last time i heard that noise was when the number 4 rod bearing went out on my 99 civic. Definitely has the same sound as a bottom end bearing noise.

 

[hvyman]

+1 on the knock. take a long screw driver and put it on various parts of the engine with the other side to your ear. where the knock is loud is where its your problem.

 

[Wade T]

I have heard many rod knock motors in the past but this is different. Strange stuff. You'd think a knock would be constant - at idle, at all rpms regardless of load.

On that note, there's a Aristo clip i'm eying.

 

[jugodegolf]

Wade excellent read here.

http://www.supramania.com/forums/showthread.php?t=20486

 

[lewis15498]

Pull your injector clips (plugs) one at a time. Run the car, it will run on the other 5 cylinders. If/when the noise changes or goes away, you likely have a bottom end problem with that cylinder.

 

[paradox616]

Can't really hear it well from the video but have you checked to see if your shims that the cams contact are within spec? mine made a similar noise round 3000rpm... is the noise constant or intermittent?

my experience with rod knock (although not on a 7m) are that it is constant and on idle.

 

[IndyMK3]

my engine only made a noise when it was above 2k rpms... and it was the number 4 rod bearing...


like stated above pull injector clips and see if the knock disappears..... and get a screw driver and use the old mechanics stethoscope method and listen to different places on your motor... have a friend work the throttle while you listen