jpandes

Like the title says I am sick and tired of the exhaust smell from my car. I am wondering what changes I can make to get it to "smell cleaner". The fumes are pretty strong while at stop lights when I have the windows down.

I have ARH LT's with a catted x-pipe, but no air pump tube. I bought them used, so I don't know if the cats are worn out and need replacing. They came without the tube for the airpump, so I am wondering if that is causing the additional fumes to escape unburned ...

Any ideas guys?

ColeTrain'sC5

Mine is an O/R X-pipe so i can understand smell I would say new cats may help.

n8dogg

I bet a tune would take care of it. You really should tune out the AIR, and remove the components.

SCM_Crash

Sounds like you may be running rich and/or your cats are bad.

ColeTrain'sC5

Yeah mine is rich especially at idle.

SCM_Crash

Interesting you're rich at idle. I was pretty sure that at idle you should be around 14.7. Have you checked your AFR with a wideband at idle?

4SFED Z

Tune and maybe cats. If its the smell idiling in the garage or something, I wouldnt worry about it. When was the last time it was tuned. AFR may be off....as stated above

Fast one

Are the exhaust manifold gaskets leaking?

c5BlackBeauty

Tune......

ColeTrain'sC5

Well you can smell fuel at idle lets just say that. It also burns your eyes and the exhaust is pretty sooty i guess is the term

03WhiteConv

Evap canister/system? I know you said it only smells when it's running but how about the dreaded cracked crossover pipe or the fuel filler tube?

A tune probably isn't a bad idea either.

Tech

There is a basic fundamental fueling feature that will try to keep partial throttle (or idle) fueling at 14.7 in closed loop. Cams with large overlap can skew O2 sensor readings at idle. Even a WB02 sensor can't accurately measure how efficient the burn is in the cylinder and adjust fuel perfectly. The most common way to combat that is with modifying the idle to stay in open loop and adjusting idle tuning with less-than-scientific means (sound/feel/smell). However, this is really only common place with big camshafts. What cam are you running? Do you know how many degrees of overlap?

I suggest going back through your exhaust system and making sure there are no leaks. It's sometimes hard to get everything to seal perfectly.

Bill Curlee

If you car is running very rich, it can significantly shorten O2 sensor CAT life. Use a digital inferred thermometer and measure CAT temp to see if there working. They should be significantly hotter than the inlet pipe temp

Data log your engine and see if your primary O2 sensors are functioning correctly The should switch high and low high and low frequently.

Clean your MAF with MAF cleaner spray

Sounds like you need an adjustment in the tune.

BC

zeevette

I had the bad smell with a cam that had IIRC, +8deg. of overlap. Since I've gone SC, I installed a blower cam with -4deg of overlap. Stink gone. One interesting note; when I installed HF cats with my first NA cam, it didn't change the smell at all.

jpandes

Thanks for all the replies guys!
I really appreciate it! I am going to try an get this fixed and I'll report back.
Off to call my tuner.

Dominic Toretto

If that doesn't work out, we can trade engines. You're in CA anyway so they probably hate your smoggy motor as is.

-Alex

Chris Stewart

Do you have a catch can? If not, it will help some.

Z06Electron

Cats

jpandes

So if my cats are bad, is it better(ie.: more cost effective) to buy a new catted X-pipe or buy aftermarket cats and have them welded in place of the old ones? Also, how important is it to have the AIR systems hooked up on LSX motors? I had a TT rotary before and the air pump made big difference...that motor functioned kinda like a two-stroke motor, anyway.

jpandes

Yup, I have a catch can.