vortecfcar

I just got a 3 inch cat put on and in the middle of summer. Ever since then whenever the car heats up the exhaust always reaks of sulfur. The guy that put the cat on said this is normal for new cats to do......this has been goin on for some time now and I think its a bit rediculus. By the way the car runs great and the AIR system is kida Jerry rigged now that the comouter has been disabled. Could the ECM being deisabled cause the Cat to run too hot and burn something ugly. Any help would be appreciated

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91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 280 grind. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, ****ty stock converter
13.24@104

chris83z28

I had a bronco with a 3" dynomax cat and it had the same smell. It never went away and the truck never got hot.

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1983 Camaro Z28
Goodwrench 350ci V8, Edelbrock TES Headers, Flowmaster Catback, MSD 6al and Blaster 2 coil, Edelbrock Performer intake, Edelbrock Performer 600cfm carb. T5, 373 rear, Eibach springs, Cervin Vega speakers, Rock. Fos. Sub, Pioneer CD,
email-chris4421@hotmail.com
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"I used to be a Mustang Guy! I didn't know the power of the dark side!!"

UnderDogRS

i ask the guy that install my exhaust.
he said the the smell is caused by rich/lean
engine(rich, i think). check you o2 voltage
to make sure your not rich. sorry i cant help more. mine, still smells sometimes.

hth,
RS

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(A.K.A FireBird88)
AOL SN: Zander0710
1992 Camaro RS 25th anniversary edition Adopted Feb,14 2000

Mods:
14x3 Open element w/ K&N filter, MSD 6a, MSD GM blaster Coil ,MSD 8.5 SC wires, AFPR,Fuel Pressure gauge(60Psi max), 3-Row Al rad. , 180* t-stat, Hooker 1 5/8 headers, 3" Catco cat, 3" Hooker Aero Chamber cat-back, "Ultimate TBI" mods

DoBeR

iTrader: (1)

We have the same problem with one of our cars. However I find that it goes away or worsens depending on which brand a gas we use. Some brands have a higher sulfur content than others. Just a thought...

vortecfcar

ok, I guess Ill just ignore it or maybe play with my carb bit. As long as perfoemance doesnt start to depreciate I will say Fuh kit.

jrr

A rich mixture and not enough air from the smog pump is the cause of the stench. If it's a three-way converter w/air tube fitting, the downstream part of the cat is platinum and needs air to do its job of oxidizing the CO and HC gasses. Incomplete oxidation because of a too-rich mixture or lack of air will cause the rotten-egg funk.

The upstream part of the cat is made of either rhodium or iridium and is used to reduce NO. I'm not aware of any particular funk from that part of the cat. Cat converters have been stinking since they were first installed in 1975.

vortecfcar

its got the air fitting attached but has no computer operating the smog setup. I I leave it like this will if F up my cat?

jrr

I doubt it will hurt the cat converter.

Remember, cars made between 1975 and 1981 didn't have computers. The lack of a computer didn't hurt the cat converters, but I do remember that they stunk more and for a longer period of time than today's comp-controlled fuel-injected engines.

raven350

But also remember that the A.I.R. pump is there fro a reason.

Those cats need the extra oxygen to help the catalyst in the convertor. Those conevrtors that use the A.I.R system depend on that air. If you do not have it hooked up, you can very well clog the catalytic convertor.

If you do not want to run the A.I.R. pump or the tubes, then get a later model cat that does not need the fresh air from the A.I.R. pump.

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Sportsman II 72 CC heads, Pete Jackson gear drive, Performance Resources chip, Edelbrock 1 5/8" headers and Edelbrock cat back exhaust, hi-flow cats, Trans-go stage 3 shift kit, Vigilante 9.5" 2800 stall convertor, SLP cold air induction, SLP roller camshaft, 24lb ADS injectors, AFPR, 3.45 rear end gears, and other goodies...


raven.com

Omar

The smog pump introduces additional oxygen into a 3 way cat via the air tube. This additional O2 helps reduce NO. If you block it off, it just wont do the job as well, and your NO numbers might be slightly higher. I have been running no AIR with no damage, and still passing CA smog.

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1989 IROC-Z 5.7L