i am sick of failing smog.

[HandBuiltXJ]

My smog guy has never ran the numbers on the cat, and just checks that the cat is there. scratch it up and make it look like it has been on there for a while and you should be good to go.

I will spray it with oven cleaner and get some good scrathes on it, or bake it with mud caked on the outside like my 93 cherokee with a high flow cat that you cannot get any number off of it if you tried..

This smog guy won't care if it is new though..

 

[GrimmJeeper]

if you get a smog guy who is a stickler for the rules he *technically* is supposed to run the numbers on the cat to make sure it is CA approved. also, exhaust shops are *technically* required to weld the cats in with the numbers facing downward so they can be read. I've only had one shop actually check, my numbers were facing up, and he got on my ass about it so I went somewhere else... problem solved.

 

[4x4wagon]

at operating temp the outlet of the cat should be atleast 10% hotter then the inlet

 

[XJ97Eric]

Make sure the catalytic converter HOT. CATS do not work good until they are HOT! Do not drive directly to the smog shop. Drive it hard and go several miles out of your way to make sure the CAT is extra HOT. After I got that tip from my dad(a smog tech told him) I have never had a problem passing.

 

[jeeperjohn]

I plan to reconfigure my exhaust and install 2 pre cats inline before the regular cat. My numbers were too close for comfort last time.

 

[Vanimal]

I plan to reconfigure my exhaust and install 2 pre cats inline before the regular cat. My numbers were too close for comfort last time.

i was considering moving the cat in front of the trans crossmember. not for smog, but so i can fit a muffler in there with the 3 link rear.
does anyone see a reason why i couldnt, legally or functionally?

 

[jeeperjohn]

i was considering moving the cat in front of the trans crossmember. not for smog, but so i can fit a muffler in there with the 3 link rear.
does anyone see a reason why i couldnt, legally or functionally?

As long as it fits it should be good to go.

 

[Vanimal]

As long as it fits it should be good to go.

my only concern is i know the distance from the manifold to the cat can be critical due to temperature loss. i would think being closer to the manifold would make it run cleaner, but i'm not sure if it would do damage to the cat or something.

 

[PetrolHead]

Technically, and this depends on the smog tech, you aren't allowed to touch or modify anything from the engine to the CAT, unless it's CARB approved. Anything post-cat is fine...but that doesn't really do you any good. I wouldn't be too concerned about temperature loss, the distance difference wouldn't be enough and when it's hot, it's hot.

 

[Vanimal]

Technically, and this depends on the smog tech, you aren't allowed to touch or modify anything from the engine to the CAT, unless it's CARB approved. Anything post-cat is fine...but that doesn't really do you any good. I wouldn't be too concerned about temperature loss, the distance difference wouldn't be enough and when it's hot, it's hot.

i wonder where the line in the sand is. I mean, if you weld in an aftermarket ca legal non direct mount cat, it usually requires some modifications to the down pipe and whatnot to fit. i wonder if i got a new aftermarket cat and welded it in before the trans crossmember if they would even notice it isnt in the stock location. i wonder if it says somewhere where the cat is specifically supposed to be?

 

[PetrolHead]

i wonder where the line in the sand is. I mean, if you weld in an aftermarket ca legal non direct mount cat, it usually requires some modifications to the down pipe and whatnot to fit. i wonder if i got a new aftermarket cat and welded it in before the trans crossmember if they would even notice it isnt in the stock location. i wonder if it says somewhere where the cat is specifically supposed to be?

I've actually had a guy pull out a book to reference where components are on a car...but I've never had a guy get under the car and measure. I bet you could get away with it if you got a CARB approved aftermarket cat and welded it in where you wanted it.

 

[scottmcneal]

Bump.Did you get it to pass? If yes, what did they do to fix it?

 

[mikedashg]

I hate smog too, and there's so many darn things it could be. Just did mine last month. Failed big time the first time around. Failed visual, high NOx, and the gas cap. Lots of vacuum line replacements and re-hook ups, a new gas cap, new O2 sensor, and seafoamed the TB did the trick. I also made the mistake the first time around of driving right to the smog shop from the house, no fwy, on a cold day. The 2nd time around (which was a 20$ re-test, and NOT free) I drove it up the freeway for while, and made sure it was up to temp/hot.

I like how you put "guarantee to pass" in it. Doesn't that stuff say if it doesn't pass you get your money back? Did you get your money back?

 

[HandBuiltXJ]

I pulled the exhaust from my HandBuiltXJ that makes my stroker pass, bolted it onto my new one, it passed with flying colors, then put original exhaust back. The cat that made it pass was a magnaflow obd2 universal.

I did not send in the g2p for my money back, I got it so cheap, it is not worth the time