Javier97Z28

ok.. I've had my Hooker LT's in since February, and I can't stand the stench of my exhaust anymore from !cats anymore...... granted, at the track and running around I could care less, but the Z is still my "nice" car and my fiancee and I go out in it when we're going out to dinner or somewhere nice... forget the windows down at a stoplight, unless you want to smell like unburnt fuel...

I believe the problem is b/c it still has factory tuning and running rich as hell now.... I have a PCM on order from pcmforless.. should this take care of my idle stench? He'll be leaning it out and such, and hopefully it will be taken care of...

If not I'm having one cat put in at the end of the ypipe and having an offroad pipe made for the track.

93TAWicked1

HMMMMM.... I don't think a Cat is going to solve your problem you must have an exaust leak somewhere which become hard to pinpoint after your exaust starts getting loud. My car has headers and an off road pipe the exaust should go out the BACK of the car. The only reason you should smell it is the windows open and a strong wind

I switch a cat in for emissions and have had it leak and the fumes get into the car. You may want to double check your exaust for leaks!!

Bob

Javier97Z28

No.. it's definitely coming out the back, and just makes a cloud of stench around the car...

Car has new ypipe gaskets (had to drop the Y recently to drop the tranny out) and it's not leaking from there... the smell is all coming out the tailpipes, and it reaks..

93TAWicked1

Damn buddy I don't know then, only time my car stinks is when I put the cat ON, then it can smell like rotten eggs. when you sat !cat you mean you don't have any not that you "hollowed" them out?

Javier97Z28

yep.. it's my Hooker LT's to a 3" Custom ypipe w/ no cats on it, then to my Hooker catback.

joeSS97

I dont have cats and it doesnt smell to bad......I dont sit there and sniff them too much either.Exhaust stinks no matter what.Maybe yyours is just too rich.

Wild1

Here's a trick that works... Take some Auto Trans Fluid and pour some into the intake manifold. You can squirt some through the throttle blades or pour some down the Brake Booster Line. Not more than 1/2 a Dixie Cup which may be about 8 capfuls. This will cause your car to smoke for a few minutes.

Look for exhaust leeks pouring out identified by the smoke. It would be helpful to have some safety stands under one side of the car so you can crawl under and peak.

My car is lowered with Hotchkis and I found a leak at the cat. It was the pipe that connected the cat to the Y-pipe. When I was in Laughlin, I was going up the damn Edgewater Garage and the bends were tight. I scraped the bottom just enough to move the clamp back 1/4 inch. That is where it leaked... plus I had a Check Engine Light pop on for a moment... EGR problem caused by reduced back pressure.

Poured in the ATF, found the loose/dislocated clamp, and now the Z is happy.

Good luck!

Javier97Z28

it's not b/c i'm sitting there next to my tailpipes sniffing it lol... if it was I think I'd have more problems than that... it's times like when I am sitting in the car in traffic with the windows down that it starts to smell bad inside the car.. if the a/c is on and such, there is no smell.

like we said..hopefully it's just too rich..

has anyone had the same problem and had the pcm programmed and leaned out and turned out better?

wild.. sounds like the ATF has the same effect of smoking like the seafoam does... when I seafoam the car I'll give it a shot.

Soma07

You cant really make the car richer/leaner during idle or part throttle.

In normal closed loop driving the PCM is hardwired maintain 14.7:1 no matter what. If the programing is richer, or leaner then it will just adjust the fuel trims (BLM's) to compensate till its back at 14.7:1 again.

I too thought my car stunk pretty bad when I went !cat a while back. I dunno if its gotten better or if I've just gotten used to it because I dont really notice it anymore. Only when I pull into the garage.

Jim_H

I just dug this up out of the cellar...

Has anyone figured out what the bad smell is at idle? It also goes away when I turn on the heat. I had figured exhaust leak, but I tightened all of the header bolts (Hooker LT's). It almost smells like coolant burning, but I am not losing any coolant. Any ideas?

twells

yeah, the smell should go away with a good tune. mine was running really rich until i got i halfway decent self tune on it and now it doesn't smell as bad. with a good pro tune it shouldn't smell too bad until you get'r done!!

thomas

Wild1

Yep, ATF does the same smoke effect as Seafoam.

Also, if you tighten down the header bolts, you might also want to check by the CAT. If you run the smoke test, you'll find out exactly where the leak is.

As for coolant, and you aren't losing any... that is tough. But if it only smells when you turn the heater on, then it could be the heater core. If the blend door opens the passage to the heater core which may be dripping a little, then you'll smell it.

Jim_H

Actually, it smells all the time unless I turn the heat on. I'm thinking of just putting my hands around the header flangs as soon as the car is satrted to feel for leaks. I don't what else it could be, but it is annoying.

Wild1

I've got an Autozone near by which loans out free tools. You just pay the deposit and get it back. Perhaps you have an Autozone or that type in your area.

Rent/borrow a Coolant System Pressure Tester. It is basically an Austin Powers type pump that fits on the radiator in place of the cap. Pressurize it up to the required amount 17-18 PSI. Then look/feel around for leaks. You'd be surprised where they leak.

Wild1

Didn't mean to steal the thread. I've got the Edelbrock TES Headers & Cat-Back with an Off Road Pipe....

Had the smell for a while. I did the smoke test and found the leak at the Off Road Pipe. The front flange came loose and the rear was missing a bolt. Fixed it and it's great...