I have a freakin knocking sound that is driving me nuts...

Sounds like somone hitting a half a coconut shell with a rubber mallet.

Its tied to the RPMS (ie it gets faster as RPM rises) and if you sit in the drivers seat, it sounds like its comming from behind the gauges, but if you put yer beak under the dash, then it sounds like its comming from the floorboards..

Pushing the clutch in or out or putting it in gear and pulling out make no difference, its still there just the same as if you were idling in neutral. Heavy load, no load, still there. It gets so fast (and the car so loud) that you can't hear it past 3K in first gear.

I rebuilt the motor and its running strong, however, I did use banzai Racing urethane mounts, which vibrate a bit more.

Can't find anything loose in the engine bay, can't think that the tac would make that much racket... If it was the pilot bearing (which i changed) it wouldn't do it with the clutch out and the car moving..., the throw out bearing is new as well, but again, it doesn't make any difference whethere you have the cllutch in or out. I checked the FMIC, doesn;t seem to be hitting anything

And its not the short shifter rattle.... i have that too, but thats intermittant and much quieter.

Anybody elsa have this noise???????

 

Somebody playing a joke on you and wrapped a tie-wrap or something around the driveshaft?

 

I know what my next prank is gonna be....

 

Isn't the knock control box back there?

jk--couldn't resist. But I know your pain, I'm tracing down a funky noise in my FB that's driving me nuts.

Btw, finally installed the FCD and it works great (Thanks again).

Scott

 

Hmmmm, I have something like that, but it doesn't sound like a coconut. It's more of a metallic ping every once and awhile, and it's coming from this little box on the upper driver's side firewall. It's about 6-8" jutting out of the firewall and to teh right of the brake master cylinder (when looking at the firewall from the engine bay). I have no idea what that component does, but it is damn annoying.

 

No, but I'm beginning to wonder about the balance on the ACT lightweight flywheel, or something at the *** end of the motor. but the motor revs so smooth, I'd have a hard time believing its that.

I'm going to adjust the banzai poly motor mounts a bit softer and see if the noise changes.... if it does, i'm switching over to the mazdatrix competition mounts and well see how they work since i have their comp tranny mounts.

 

Does it sound like a relay clicking on and off??

 

Hey-what about your fresh/recirc air door loose & rattling around? Or something related, the actuator, linkage, etc...

 

How about a spark jump at the trailing coil?
I once had a bad HV wire that made a loud enough tic tic tic, to be heard inside the car.

 

Its not a tic, metallic or electric sound, its deeper than that and more of a knock than a tic.. might investigate the Fresh air door though, but its definately sourced from engine vibration cause it NEVER misses a beat at idle... never. its ALWAYS knocking....

 

How much e-shaft play do you have?, if you know...

 

I almost didn't catch a bad T/O bearing that would have sounded like that.
The contact ring was not concentric with the guide sleeve.
That would make the bearing want to wobble & knock on the guide sleeve.