trying to cliff note it,

tried 3 cat converters (current OEM)
2 cat backs (current 2.5)
4 exhaust manifolds (current is DC ceramic 4-2-1)
like 5 different gaskets whereever there is an exhaust gasket, except the head-to-manifold spot, thats origional, however it doesnt seem that spot leaks.

Seems the leak is comming from the shifter area/catconverter to header area. I have replaced this gasket with a $20 oem one, and 5 days later it returns, full force again. Almost like if I take a sharp turn, the donut starts leaking, and keeps leaking, untill I replace it.

I have an exhaust, which when it leaks, i cant hear the exhaust, only the sound of the leak. When its not leaking, all I can hear is the sound behind me (the muffler)

Seriously I have tried everything, i have the exhaust aligned so non of the rubber hangars are binding, everything is very sturdy.

seems like the donut is being warped/crushed by the engine movement or something. Could I use copper gasket RTV covering the donut gasket? or will this just burn up making a larger leak? This is really not funny anymore, its the ONE thing I cant get rid of, and have 0 power when its leaking. If anybody has any oppinions i would really like to hear em. thanks


1996 d16y8

p.s could it be from past crap/very slight rust on the end of the header? the spot where the donut gasket fits over, has a very light ammount of rust on it. However can the air pass through the back side of the gasket? the non tapered part? you would think the pressure of the spring bolts would secure it good enough not to leak, plus the ID of the donut gasket is so snug with the collector, that it would be hard for it excape.




Modified by MidwestCartel at 3:29 PM 4/29/2007

 

pics needed.

 

I dont have a cam presently, but what do you need pics of? alignment and that sort of stuff? i dont see any holes or gaps, but somehow air is seriously getting out from somewhere durring load.

not @ idle, but more like 1000rpms-redline at any gear, about 1/4th throttle and on.

so @ idle you cant detect the leak, even when stuffing the tail pipe with a stuffed bunny rabbit, I cannot hear/find the leak.

 

So....how do you know there is an exhaust leak..

 

oh man are you kidding? driving I can hear it. its like its only under load. You can tell with an exhaust when the sound is comming from the rear, vs the front when you take your rear seats out.

When the leak is present, there is 0 noise from the rear. and I have 0 power, it boggs heavily and makes a very loud HISSSSing sound thats very tingy

 

a leak wont make a power loss, at least for a single slammer.

sounds like a different problem.

 

you sure about that? you loose a hell alot of velocity with that.

well whatever the hell it is, its bad, could it happen to be a leak on the block somewhere? would a headgasket possibly sound like this? i dont think i have a head gasket leaking, but its definately something.


Do you guys this I should just grab a test pipe with a flex? I would have to run it open header for a day while I get a flex/testpipe built

 

maybe the torque mounts are so worn that the motor is moving so much its causing the exhaust to leak, but it shouldnt if the bolts are tight

 

How long have you had the car?

Maybe your brain started working and you came to the realization that:

A) Your civic <> Enzo
B) Your civic has a stock SOHC which isn't fast

...

Exhaust leaks aren't that hard to fix, jam the tailpipe nice and air tight with a rag or towel or something and rev it the hell up, if you can't find the leak then, you shouldn't be allowed near a car. It's pretty damn obvious.

PS: If it stalls out you don't have a leak, or at least nothing sufficient.

 

ive already covered the tailpipe with a stuffed animal, and no there was no leaks. which is wierd, its almos like a pin hole leak.

however you can feel/hear the difference when the leak is present, i have 0 throttle response. When I slam on the gas, it just jerks and kinda boggs, and RPMS dont climb.

Ive replaced everything to be replaced, thats why I nailed it down to exhaust.

things ive replaced
plugs/wires/cap/rotor/dizzy/o2/throttle body/all exhaust parts/most gaskets/pretty much everything but the LMA's. Valves are in spec, maybe on the tighter side.

its my exhaust which doesnt line up, I have a different axle back on the car than which came wiht the cat-back. however the alignment is slightly off, not too much.

again, it changes from stop light to stop light sometimes. I can take a sharp right turn, and the leak is gone, I can hit a bump, its back.

Seriously this is bugging me, cant find the leak, but can totally hear it only while driving in 2nd-5th from around 2k rpms up. its VERY present when im in 3rd gear, at 2000rpms and I floor it, its like im running open collector.


There are no holes, the o2 sensor is tight, I even removed the gasket last night, and it looks brand new still. The spring bolts are very tight, and I changed out all the gaskets again last night, same thing, maybe worse now.

Im about to give up on it, and let my engine run lean. the brand new plugs are white, and I can hear back fires now in the exhaust, loud pops.


[edit] I just called a local shop, and to have a flex pipe made to replace the cat converter, its about $25. Anybody think this would be my best bet, if my catback was crooked?


Modified by MidwestCartel at 8:28 AM 4/30/2007

 

Valve adjustment FTW.

/thread.

 

yea its the connection where the donut gasket fits into the converter, i guess the seal isnt tight enough, its at JUST the right angle to make a hairline leak.

Funny, since i was soo pissed at the car that I held WOT all the way to work, and stayed the speed limit. I think I might have damaged something.

valve adjustment being too tight can result in a leak?

 

No a valve adjustment could definately be the ticking-esque noise you're hearing.

A car needing a valve adjustment is often mistaken for an exhaust leak as they sound so similar.