Help - new FI HFC leaking at gaskets on exhaust side
 

Installed Fast Intentions HFC, and have been fighting with the SES light for over a week now. I spoke with Tony @ Fast Intentions and he helped narrow it down. I went under the hood and tightened alot of fasteners on my Stillen CAI system (surprised to find so many!), but now I have a different issue.

The gaskets are leaking between the stock Nismo CBE and the back of the cats. I found out by observing condensate dripping from them after starting the car. I've tightened the bolts a lot. These are new gaskets and new bolts. I'll post a video once it's done uploading.

Assuming my flanges are all straight, why can't I get the gaskets to seal? They're symmetrical (as far as I know) and shouldn't have a specific orientation, so what gives? Anyone else come across this issue?

Video:
http://i1197.photobucket.com/albums/...321_172022.mp4

This would be a nice assumption, but have you actually checked the flanges? Other than that, not sure man. If the gaskets are new, it's unlikely they are the culprit.

I had the same problem when I installed my AAM exhaust. After firing it up, I had leaks on all fours seals after the cats. One being worse than the others. I wound up redoing those flanges by applying cooper seal to the four gaskets. All turned out great.....no leaks.

RTV the hell out of it and go on about your day.

I would take a wire brush bit attached to a drill to clean the mating surfaces. A gasket won't work if both surfaces werent somewhat clean.

Yea i put a straight edge on them to check. I ended up using permatex, so we'll see if I solved it.

:iagree:

Got the SES light again. However, I admit that I didn't let the copper permatex set for 24 hrs before returning to service (more like one hour, I just didn't have the time to let it sit), and I only re-did the y-pipe to HFC flanges. Looks like I'll have to pull it all down this weekend (have four new gaskets on order), and will apply sealant to all four flanges. Sigh.

I let mine sit for nearly two days. Overkill, however, I applied a fair amount to each side of the gasket.

What I did was just snug up all 3 nuts,than do another round of tightening on all 3,THEN I torqued the sh:t out of them! Kind of like how you do the lugs on the wheel.

Won't work if the flanges are off. I even purchased higher strength hardware thinking I can muscle stainless steel. I was wrong.......even afraid I would crack the weld joints. The Ultra Cooper solved my problem......simple and solved my problems.

I just re read the post and seen he's using high flows in conjunction with nismo exhaust. I could see how they might not match up. :tiphat:

So you had some exhaust leaks and resolved them with permatex? I hope that's the case for me, I'm gonna be pissed if that SES light still comes up..

Yes, as stated, I had four flange leaks and used Permatex Ultra Copper to stop the leaks. I waited longer than the recommended 24-hours to fully dry before I fired up the Z and drove off.

The SES can be or not be related to a problem with your exhaust. I suggest after you correctly Permatex your seals is to reset your ECU.

Here's a good link to do so:

http://www.the370z.com/engine-drivet...ve-method.html

I believe I am battling a similar issue - could you hear the leaks in the cabin while revving? Say like above 4k?

Unless you have a huge gash in your exhaust, I doubt so. Just look at your flanges while in neutral and have someone press the accelerator.

Spent Saturday taking it all apart, cleaned flanges with a Dremel wire wheel, and permatex'd the sh*t out of everything. Took a reading today after running errands (pic below).

Now we wait.

http://i1197.photobucket.com/albums/...328_172704.jpg

http://i1197.photobucket.com/albums/...328_174952.jpg

After driving today. A permanent code was still stored in the ecu for run lean condition, and that has since disappeared (something i learned: you can't erase permanent codes, only your ecu can determine if the issue is resolved)
http://i1197.photobucket.com/albums/...329_164334.jpg

permatex=poop in my experience, my berks where also leaking with permatex until I got some damn legit gaskets... no more leaks or codes 7k

Yea Dave I've got both gaskets and the permatex on there. Hoping the permatex will help seal up imperfections.