I know some of you have had exhaust leaks, and replaced your gaskets. Did you all have a CEL code when the leaks occurred? And which code?

 

It can cause an oxy code, yes.

 

Short answer, yes.

In my case a P0420 "Oxygen below threshold in the Catalytic Converter" or simply as "Catalytic Converter Inefficiency"

And no, it's not my high flow cat, my rear manifold to y-pipe exhaust gasket leak (aka the "Turbo") has just gotten worse and worse as the days go on (Only recently the code started showing) and I care less and less....

In my situation, The error is tripped by cruising @ low rpms (2-2.5k) for a long time. To make it go away, run at WOT for extended period of times a few times... as for exactly how long? I've yet to measure but the light always goes off after some hard trips to the redline. Clearing the code won't work, as soon as the emissions computer is ready the light will pop right back on.

Again, this is how my car is in it's situation... Yours could be different.

 

Did any of you NOT have a CEL, or had a different CEL with a manifold to y-pipe seal blow-thru?

 

I have a constant (bank 1, sensor 1) oxy sensor code. Will not go away with my WS Y installed. Got rid of the leaks and the mpg's went up to 'normal' for my driving. I was running really rich and it was in part due to the exahust leak. I used exahust putty on mine to get it sealed up. What's goin on anyway?

 

I think that's the code I am pulling. P0171 or 0115, lean bank one.

I have a small leak on the Y-pipe rear down. I am gearing up to do the flange gaskets, but one orger told me that he had a leak but was not pulling a CEL. I wanted to check whether I am overthinking this. I don't want to change the gaskets only to see the CEL at the end of the day.

So correct me if I am wrong, but the leak is letting in air that the O2 sensor reads as not enough gasoline in the system, the ECU tries to adjust but the air keeps coming, so I end up running RICH as the ECU puts in more gas but the code is for too little gas and too much air. Is that right?

 

Wow ... that's a mouthful! lol That is how I understand it, yes. I have considered rigging up some sort of o2 simulator (I know they make generic ones) to get rid of the code, but so far I haven't woried about it. I fixed the leak (as small as it was) and I still get the code. Have replaced the oxy sensor(s) with new ones on several occasions to no avail. Oh well is what I say. lol

 

That O2 simulation sounds really nice. (EDIT: I don't think they work on main O2's, only on the rear)

i have some walker flange gaskets on the way, i just need to grow a pair before they get here.

if you repaired your leak with exhaust cement, you didn't necessarily get the leak, so that's probably why the code persists. Or did you actually drop the y and put some new seals?

I am like two weeks past my emissions expiry, and i can't afford to have a mechanic do this job, especially one eager to drill holes in the manifold for a $1000. At least my local nissan dealer has the mani studs in stock, which is a change...