exhaust smoke after cat removal

**mvvette97** · 09-01-2006, 07:56 PM

Just wondering if this was normal? It smokes at WOT and while letting off. I didn't notice this till I took off the cats. Another thing, I had some bad gas so it had a bad ping so I put a bottle of 104+ octane boost in it, well my wife took it to town later and put one more bottle in because she didn't know I had put a bottle in. So I had about 3/4 of a tank of gas and two bottles of 104+. I have enough octane booster for 50 gallons and have it in 10 gallons. Would that make it smoke

**Redphoenix1998** · 09-01-2006, 11:47 PM

running rich at WOT, that's what it sounds like. Might be the cas, drive it till it's a 1/4 and see how it goes after that. If it still smokes but not a lot, just a puff, it's normal

**0rion** · 09-02-2006, 06:37 AM

what color is the smoke?

**ss~zoso~ss** · 09-02-2006, 03:22 PM

if its black its running rich

**YoMommasTA** · 09-02-2006, 05:03 PM

Originally Posted by mvvette97

Just wondering if this was normal? It smokes at WOT and while letting off. I didn't notice this till I took off the cats. Another thing, I had some bad gas so it had a bad ping so I put a bottle of 104+ octane boost in it, well my wife took it to town later and put one more bottle in because she didn't know I had put a bottle in. So I had about 3/4 of a tank of gas and two bottles of 104+. I have enough octane booster for 50 gallons and have it in 10 gallons. Would that make it smoke

the reason you see the blue smoke now is because the cats burn EVERYTHING so completely no oil smoke can be seen.Thats why a LS1 car can use 1qt of oil every 1k and you never see smoke.Once you remove the cats the oil doesn't get burned up and you see the blue smoke.

**mvvette97** · 09-02-2006, 08:51 PM

today I found that I have oil in the intake behind the throttle body. Do i need a catch can?

**Sarge** · 09-03-2006, 05:43 AM

Probably....
http://www.ls1.com/forums/showpost.p...75&postcount=4
However I'm curiuos...did you delete the rear O2 sensors? If not your computer is telling your engine it needs fuel and dumping like a big dog....

**mvvette97** · 09-03-2006, 06:44 AM

Originally Posted by Sarge

Probably....
http://www.ls1.com/forums/showpost.p...75&postcount=4
However I'm curiuos...did you delete the rear O2 sensors? If not your computer is telling your engine it needs fuel and dumping like a big dog....

I have the O2 sims

**Sarge** · 09-03-2006, 07:07 AM

Originally Posted by mvvette97

I have the O2 sims

Good....yeah I would invest in a catch can.....what A/F are you running at WOT?

**cailey37** · 09-03-2006, 05:21 PM

Originally Posted by Sarge

Probably....
http://www.ls1.com/forums/showpost.p...75&postcount=4
However I'm curiuos...did you delete the rear O2 sensors? If not your computer is telling your engine it needs fuel and dumping like a big dog....

I've got the same vent cap on mine and I have a problem with the oil still being flung up into the filter....so much so that it will leak out the filter when it sits.......I've got a catch can and all........I almost wish someone would make a crankcase filter with a little bit of a bend on it instead of just coming straight out......dont know if that would help or not.....

**NHRAMAN** · 09-11-2006, 10:49 AM

Originally Posted by YoMommasTA

the reason you see the blue smoke now is because the cats burn EVERYTHING so completely no oil smoke can be seen.Thats why a LS1 car can use 1qt of oil every 1k and you never see smoke.Once you remove the cats the oil doesn't get burned up and you see the blue smoke.

CORRECTOMUNDO 100%...

**SSpdDmon** · 09-11-2006, 11:18 AM

Originally Posted by Sarge

Probably....
http://www.ls1.com/forums/showpost.p...75&postcount=4
However I'm curiuos...did you delete the rear O2 sensors? If not your computer is telling your engine it needs fuel and dumping like a big dog....

Not quite...the only function of the rear O2's is to determine whether or not the cats are doing their job. That's why you can remove them and drive on the SES light without issue. The front O2's are the ones responsible for fueling.

As for the smoke issue, LS1's run pretty rich from the factory at WOT. If you have bolt-ons running the stock tune, chances are your part throttle fuel trims are positive. Positive fuel trims are transfered to WOT, which richens the mixture even more. I wouldn't be surprised if you hopped on a dyno w/ a wideband and you saw 11.3:1~11.5:1 air fuel ratios. That combined with a little oil consumption is enough to give you a little cloud out of the exhaust pipe.

**specialized.1** · 09-11-2006, 05:38 PM

Hey Sarge. Well I have read a gew of your posts and you seem very knoledgable about all this ls1 stuff. I think your car must pull hard. I notice the only thing you didn't change was the dipstick. On quick question, where are you pulling into the catch can from? I bought a catch can kit from TPIS and it seems to be working well. I just pull off the stock valvecover, and stock hoses with a open pcv valve. Do you approve of this setup?