Timeline:

Replaced a couple vacuum lines with silicone hose, and took off and reinstalled IC piping. During this time I left the TB opening open, but had taped off both ends of my FMIC and my Turbo compressor outlet.

After reinstalling everything, the car idled horribly and was undriveable. Solution to driveability and idle was a new IACV. Car idles fine now.

This lasted about 30 minutes of actual driving, the time it took me to get from Kailua to the Stadium on H3. I did not wind it out, or do any WOT pulls, just casual driving. Once I got off the freeway, I noticed I had a very large vibration from my engine.

Diagnosis: Motor Mount failure

It was my motor mounts, but the problem persists. It was obviously the large vibration in the first place that took out my stock mounts, and with the group-n mounts the block doesn't vibrate 2-3" back and forth, but I can still feel the large hit of the offbalance whatever when I put a hand on the manifold.

I noticed a sound also, one that I never noticed before. Quite honestly, I'm freaked. I fear this might be my slight lean condition ( 16AFR idle's ) finally taking a toll. I took a video and would appreciate it if you all would have a listen.



Thanks so much for your help everyone!

 

is this noise a constant or does it go away when you pass a certain rpm? what's your mileage on the car btw?

 

hmmm

 

I think its the flux capacitor.

Just kidding. Hopefully somebody can help a fellow Ryan out!

 

Though It sound like a slight knock but yours has a higher pitch sound than a knock.

 

I can't really tell from the sound, but hey, I'm half deaf anyway. Just ask my girlfriend. Maybe try and check your header temps to confirm that all the cylinders are firing properly. That's the only think that I can think of right off hand that could cause an imbalance without sounding like TEOTWAWKI.

 

I still don't know what it is but I'd definitely check your timing. oil starvation?

 

Q what mods do you have and have you had it tuned? what boost are you running?

 

Deadbolt super 16g
APS DR500 FMIC, Inlet, an 65mm cai
detachwerks 720cc injectors
Perrin EBCS
walboro 255
turbo back

its tuned for current mods and has been for all past mods. Oil changes have been up to date, I use M1 10w30.

 

Ryan, so what "sound" are you referring too? Is it the "sound" @ 36secs.??

 

You can't even hear it in the video very well, the injectors are just too loud. It's very easy to hear in person though. It's most pronounced when the video was in the middle of the engine.

 

I hear it... it's the low tapping noise. the injectors are very loud LOL.

have you received any CEL in between the problem?

 

could it be the tune?

 

when did u notice the isssue

 

Your said your AFR's are 16ish at idle, what about when you drive it normally in cruise? Do you hear a marble bag-like sound?

Unusual for it to be engine knock without having an initial catastrophy at first.