Exhaust stink!

[Some1esle]

Replaced the stock exhaust about 4 or 5 months ago with 3 inch in flowmaster cat, 2.25 inch pipe about 12 to 18 inches, then a flowmaster delta 50, 3 inch tailpipe, the $12 tip from Walmart or something... the manifolds, and y-pipe are bone stock. the intake is stock with a drop in K&N. This setup was recommended by the guys at Flowmaster.
Ok now to the problem:
aside from an idle problem, the truck runs great, sounds like it has nuts the size of a taxicab, and has greatly improved HP. The exhaust smell like a cross between rotten eggs, sulfer, and ass. this is only when the vehicle is warm. and in southern Arkansas that seems to be 99.9% of the time.
Any Ideas...

 

[slacker]

yep ... its the cat ...guarenteed .

 

[Gh0st]

rotten eggs...defitnaly the cat

 

[Some1esle]

rotten eggs...defitnaly the cat

ok now that that is established.....
is there a way to make it not stink?

 

[slacker]

yep ... replace .


usually , they do that because of deposits .

 

[Some1esle]

yep ... replace .


usually , they do that because of deposits .

So it would be bad from the get go...

 

[slacker]

it was NEW right ?

I would think you have and issue with the exhaust size? and computer control... maybe tuning is required ?

depending on the year of your unit .. i'd say some adjustments are required with the "larger" exhaust .

 

[Some1esle]

it was NEW right ?

I would think you have and issue with the exhaust size? and computer control... maybe tuning is required ?

depending on the year of your unit .. i'd say some adjustments are required with the "larger" exhaust .

I see... I need to do some tuning , so It will probably workout in that.

Thanks

 

[ovrrdrive]

Did you pull the efi fuse for a few seconds after you got the exhaust done?

It can help to reset the ECU so it relearns the fuel curve sometimes. With increased exhaust flow there will be a need for more fuel.

Other than that, that may just be a side effect of a high flow cat. If you think that's bad you should smell mine without a cat at all. :awais:

 

[Some1esle]

EFI fuse... I had the 3 in pipes all the way back at first.... Yep, it was worse. I also experienced a major lose of power due to lack back pressure. That's why I dropped back down to 2.5 before the cat, and 2.25 between the cat and the muff. Oh ya I also had the Delta 40 single chamber on there before as well. I changed out to delta 50 three chamber muff. I will do the efi fuse removal. That could be a big part of my low idle as well. Then I'm going to change out to the AMSOil air filter, from the K&N after reading some results on those.. Yep, I'll check the MAF door/gate at the same time, and grease it with white lithium. Then professionally timed, and tuned.. See what happens from there...

 

[Daemon]

Just out of curiosity, how much did that exhaust setup cost you? I'm looking for a few hp for my 3.slow so am researching 2.25-2.5 inch catback exhaust systems.

And yes, a smelly cat is usually a sign of a bad cat, or bad tuning (too rich). Since your cat is new, and you're experiencing other issues, sounds like bad tuning.

ian