Help with smog
Thread Starter
Registered User
Joined: Jul 1999
Posts: 113
From: Los Altos, CA, USA
Help with smog
I need a little help from some of the smog gurus.
I have a 95 Firebird Forumula 6spd LT1 ~125K miles
The car is pretty much stock with the exception of a K&N FIPK, an MSD Digital 6 Plus, and a LT4 knock sensor.
The car is a single cat model and the cat was replaced about 3 years ago.
I recently failed smog.
HC was slightly above passing as was CO, NOX was around 1700.
I replaced the EGR valve and retested but there was not real difference.
The car runs really well, no stumbles and around 19MPG, so I am a bit puzzled by the emissions
Anyone have any ideas? I can post actual smog numbers if needed
I have a 95 Firebird Forumula 6spd LT1 ~125K miles
The car is pretty much stock with the exception of a K&N FIPK, an MSD Digital 6 Plus, and a LT4 knock sensor.
The car is a single cat model and the cat was replaced about 3 years ago.
I recently failed smog.
HC was slightly above passing as was CO, NOX was around 1700.
I replaced the EGR valve and retested but there was not real difference.
The car runs really well, no stumbles and around 19MPG, so I am a bit puzzled by the emissions
Anyone have any ideas? I can post actual smog numbers if needed
Registered User
Joined: Jun 2003
Posts: 78
Re: Help with smog
Originally posted by Lowend
I need a little help from some of the smog gurus.
I have Forumula 6spd LT1 ~125K miles
The car is pretty much stock with the exception of a K&N FIPK, an MSD Digital 6 Plus, and a LT4 knock sensor.
The car is a single cat model and the cat was replaced about 3 years ago.
I recently failed smog.
HC was slightly above passing as was CO, NOX was around 1700.
I replaced the EGR valve and retested but there was not real difference.
The car runs really well, no stumbles and around 19MPG, so I am a bit puzzled by the emissions
Anyone have any ideas? I can post actual smog numbers if needed
I need a little help from some of the smog gurus.
I have Forumula 6spd LT1 ~125K miles
The car is pretty much stock with the exception of a K&N FIPK, an MSD Digital 6 Plus, and a LT4 knock sensor.
The car is a single cat model and the cat was replaced about 3 years ago.
I recently failed smog.
HC was slightly above passing as was CO, NOX was around 1700.
I replaced the EGR valve and retested but there was not real difference.
The car runs really well, no stumbles and around 19MPG, so I am a bit puzzled by the emissions
Anyone have any ideas? I can post actual smog numbers if needed
In all honesty, don't waste your money: take it to a mechanic right away. My car (a 95 Formy with 45k miles) failed the sniffer, because of excessive HC emissions. They did a 'motor-vac', which I later found out was nothing more than Seafoam. HC was STILL not passing, so they swapped out my EGR valve, and I passed
The excessive NOX reading, even after the EGR swap puzzles me. The EGR valve is the primary control for NOX emissions. Are you sure you 'tuned' it correctly?
If you want to pass, for the minimum amount of money:
Seafoam....$12.00
Change the oil/filter
New air filter
New Carsound 3" cat off e-bay (good cats, made by Magnaflow)...$45.00
1 bottle of rubbing alchol+1 tank of gas'
Run the car for like 15 miles on the highway
The key is the new cat. Even a horribly failing car will pass with a new cat...as long as you havn't driven on it too much. First and foremost, though, make sure the engine is getting enough EGR.
Last edited by LT1Noob; Sep 3, 2004 at 11:10 AM.
Thread Starter
Registered User
Joined: Jul 1999
Posts: 113
From: Los Altos, CA, USA
Yeah - thats what I was thinking.
The Cat is onl y 3 years old... I wonder if changing it will really make any difference??
I did use some Clean Power in the fuel system - same type of stuff as sea foam, mainly touene.
Anyone else have ideas...
The Cat is onl y 3 years old... I wonder if changing it will really make any difference??
I did use some Clean Power in the fuel system - same type of stuff as sea foam, mainly touene.
Anyone else have ideas...
Registered User
Joined: Feb 2003
Posts: 155
From: Orange County, CA
I think that high NOX means that your burning too HOT/lean.
High HC's mean too Rich.. or not hot enough.
You could always just get a custom chip made for your car and mods.
I did the, Purchase a Cable at AKM cables.
and wrote to PCM 4 less and had Bryan make me a program, it can fix rich/lean conditions as well as find some more Horses.
Cable = 90 bucks. OBD1
Program = 50 Bucks.
Might be cheaper than buying all sorts of stuff to fix your problems temporarily.
High HC's mean too Rich.. or not hot enough.
You could always just get a custom chip made for your car and mods.
I did the, Purchase a Cable at AKM cables.
and wrote to PCM 4 less and had Bryan make me a program, it can fix rich/lean conditions as well as find some more Horses.
Cable = 90 bucks. OBD1
Program = 50 Bucks.
Might be cheaper than buying all sorts of stuff to fix your problems temporarily.
Thread Starter
Registered User
Joined: Jul 1999
Posts: 113
From: Los Altos, CA, USA
It just seems to me that this car outta pass smog considering that it is pretty much stock.
I suspect somthing is wrong since it failed emissions on all three fronts.
NOX was way out of line but the others failed too
I suspect somthing is wrong since it failed emissions on all three fronts.
NOX was way out of line but the others failed too
Registered User
Joined: Jul 2001
Posts: 280
From: South Bay Area, CA U.S.A
I wanna know if anyone has passed smog with a messed up 02. I'm throwing a P0141 code which right before the CAT. I deleted the code and was wondering if I could still barely pass smog? What do you think?
Thread
Thread Starter
Forum
Replies
Last Post