Exhaust stinks, bad tune? Need AIR, Need EGR?

**General Z** · 01-27-2009, 07:53 AM

Already searched, but still have questions.

I've got a 99 Z28, with a Hot Cam, long tubes, Borla, Pulley, LS6 manifold.

I had it dyno tuned, but the shop is now out of business and I think their tune may have been crap. I have removed my AIR system and EGR as well. I'm running O2 sims in the rear and some Denso O2's up front.

The car stinks. Like, burn your eyes out of your head stink. According to the scanmaster, its always adding fuel. I think the last time I drove it the LT trims were positive 5 and positive 7. Pretty sure that's where they were.

When I bought the exhaust, I thought ahead and got a system, FLP, that had interchangeable cats and straight pipes.

So the question is, if I do nothing but put the cats in, and leave everything else alone, will my stink go away? Or, do I need to run the EGR and AIR if I'm going to run cats?

Secondly, could the stink be eliminated by a better tune, and not put the cats in? The car is so lightly modified, that I'm sure a mail in tune would be just as good as a dyno tune. I did all this stuff back when things were kind of in their infancy regarding these cars and engines.

Now I'm at a point in my life, where being loud and fast are only so important. Getting rid of the stink is more important.

Thanks

**bigrondownhiller** · 01-27-2009, 01:34 PM

Sounds like it needs a better tune. The cats would only help for a little while until they get clogged from to much unburnt fuel. If you dont have a local tuner a mail order would be good.

**sunsetorangess** · 01-27-2009, 02:53 PM

Like said above, it sounds like you got a shitty tune and theres a reason there out of business. Anywho, you should probly start by getting that fixed. You can check out "FROST" on here or lsxtune.com. Personaly never used them but have been sponsers for some time and iv heard nothing but positive feedback.
Or check with your local car clubs and see if there is a local tuner that can take care of ya.
J

**TransAm11973** · 01-27-2009, 04:20 PM

if it smells like sulfur or rotten eggs then your cats are probably bad

**General Z** · 01-27-2009, 05:04 PM

I don't currently have the cats installed. That was the question, would installing the cats make it smell better or do I need a new tune? I'll definitely contact the Frost and the other company and get their opinion as well. Thanks

**TransAm11973** · 01-27-2009, 05:06 PM

oh i am sorry, i didnt read that closely........well with out cats your exhaust will have a strong smell...mine does and its tuned just right....not to say that you dont need a new tune....but no doubt with out those cats your exhaust gases are gonna smell stronger

**General Z** · 01-27-2009, 06:09 PM

So can I install the cats without having the EGR or AIR hooked up? My main concern is the strong smell. I have a new baby that I want to take in the car come spring, but can't see doing that with this strong exhaust smell. I'm past the point where being loud or losing a few HP really matters to me.

**sunsetorangess** · 01-28-2009, 01:01 AM

Congrats on the Baby bud, You wont have any issues instailing the cats once again. You said you have high flow cats right?
J

**General Z** · 01-28-2009, 05:03 AM

Thanks,

Yes they are high flow, I don't remember the brand, as they are tucked away in the garage. Can I install them without hooking the AIR and EGR back up? Will they make the smell go away, or will I still require a new tune, regardless of the cats?

**bigrondownhiller** · 01-28-2009, 07:12 AM

the cats wont help long with the fuel smell. I would get a tune also. If it is running that rich you are losing some power.

**ss~zoso~ss** · 01-28-2009, 07:20 AM

i'd get a tune, and you'll actually pick up HP cuz if you're running really rich you're loosin power, if the tune doesn't help the smell, you can put your cats on also

**General Z** · 01-28-2009, 07:22 AM

Yep, that's what I'm going to do, send the pCM to LSXtune and then see how bad the car smells. Like you say, I can always pop the cats in later.

**0rion** · 01-28-2009, 08:03 AM

keep in mind that a car without cats is going to stink period.......it's just gonna be stronger than one with cats on it. Now I can't say if yours is excessive without being there but a cammed car without cats is going to smell. Put your cats on and that should help the smell quite a bit but like others said if you're plus 5-7% on ltft's you need another tune.