New exhaust, need to pass emissons
Thread Starter
Senior Member

Joined: Jan 2009
Posts: 611
Likes: 3
From: DE
Car: 1990 Firebird Formula
Engine: LB9 - 5.0 TPI
Transmission: 700R4
Axle/Gears: 2.73, LSD
New exhaust, need to pass emissons
Got the car 2 years ago and barely passed the third time. The shop I took it to back then said I passed once the cats were hot. Exhaust looks like it's the original with the exception of the headers, which look like long tube headers. I've been thinking about getting a magnaflow setup with mid lengths and possibly going back to the 195* thermo. The car was running very rich is what I was told. I feel that my 02 sensor may not be getting hot enough with the longtubes and lower thermo. Does anyone think that the Magnaflow setup with midlengths, and possibly higher thermo (at 180 now) get me through? I also have an exhaust leak if that means anything as far as emissions.
Member
Joined: Apr 2008
Posts: 378
Likes: 0
From: Macedon, near Rochester, NY.
Car: 85 TA (sold), 88 Corvette, 02 Monte
Re: New exhaust, need to pass emissons
All I can tell you is that its very easy to switch to a heated o2 sensor.
How does your car even have room for cats if it has long-tubes? Where are they?
How does your car even have room for cats if it has long-tubes? Where are they?
Banned
Joined: Mar 2010
Posts: 474
Likes: 0
From: In my garage next to my car
Car: 89 Red IROC
Engine: 5.7
Transmission: 700R4
Axle/Gears: 2.77
Re: New exhaust, need to pass emissons
A heated O2 may be all you need. Plus some of these smog guys are idiots anyway. The cat does not work unless its hot. These guys will test on a cold motor and it will fail.
Do you have a smog print out that you can show the results?
Running rich I am thinking maybe too high HCs. How was the NOx? Where are you or does your state test all these things?
You can also check your timing if the test station did not or said it was ok and maybe replace the cat.
Do you have a smog print out that you can show the results?
Running rich I am thinking maybe too high HCs. How was the NOx? Where are you or does your state test all these things?
You can also check your timing if the test station did not or said it was ok and maybe replace the cat.
Supreme Member
iTrader: (25)
Joined: Feb 2006
Posts: 7,260
Likes: 5
From: Manteca,California. Nor Cal.
Car: SOLD IT. Mopar guy only now.
Engine: gone
Transmission: gone
Axle/Gears: gone
Re: New exhaust, need to pass emissons
I dont think you need to change your headers. but if the cats are original they probably need changed.
Thread Starter
Senior Member

Joined: Jan 2009
Posts: 611
Likes: 3
From: DE
Car: 1990 Firebird Formula
Engine: LB9 - 5.0 TPI
Transmission: 700R4
Axle/Gears: 2.73, LSD
Re: New exhaust, need to pass emissons
The exhaust wraps way to the right, cat is under the passenger seat pretty much. The timing was adjusted about a month ago so we'll see how that goes. And it wouldn't surprise me if the cat does need replaced because the exhaust on the bird is pretty shot. I planned on getting my exhaust done anyway.
And I will look into the heated O2 sensor, I never heard of that before.
And I will look into the heated O2 sensor, I never heard of that before.
Banned
Joined: Mar 2010
Posts: 474
Likes: 0
From: In my garage next to my car
Car: 89 Red IROC
Engine: 5.7
Transmission: 700R4
Axle/Gears: 2.77
Re: New exhaust, need to pass emissons
Where did it fail at??? You really can't get the proper answers unless you tell us.
The Cat and EGR a usually the two big heavy hitters but it still helps to know.
And later vehicles, at least 96+ are heated O2. They save on the time it takes for the exhaust to heat the O2 itself as they also need to be hot to be working.
The Cat and EGR a usually the two big heavy hitters but it still helps to know.
And later vehicles, at least 96+ are heated O2. They save on the time it takes for the exhaust to heat the O2 itself as they also need to be hot to be working.
Thread Starter
Senior Member

Joined: Jan 2009
Posts: 611
Likes: 3
From: DE
Car: 1990 Firebird Formula
Engine: LB9 - 5.0 TPI
Transmission: 700R4
Axle/Gears: 2.73, LSD
Re: New exhaust, need to pass emissons
Delaware. I'll see if I can find my old numbers they printed out for me. Did put a new EGR a couple months after inspection because it went bad. I may actually get through this time, just anticipating another failure because she does run rich still, I even get an SES once in a while. Pull the codes and its Oxygen Sensor Rich Detected.
Thread
Thread Starter
Forum
Replies
Last Post




