Passed MD emmissions finally, Guess why it failed, answer inside.
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
Passed MD emmissions finally, Guess why it failed, answer inside.
1990 L98 with replaced ZZ4 motor headers, high flow random cat, Borla exhaust, recently replaced fuel pump and fuel filter. Car sat for 3 months while I was in the middle east on deployment. I come back and its time to go through the Maryland rolling dyno emissions test. I got all my EGR hooked up, and smog pump thing, I pass the unleaded fuel cap pressure guage thing. I pass the visual check for a catalytic convertor. I fail miserably the measuring of gases out the tailpipe. It it running high in both co2 and nox (I think those were the terms). I am told you got a month and bring back a bill for $450, to get a waiver for a year. The car ran fine, and passed the emmisions test 2 years before with the new motor. The only thing different was a new hi press fuel pump, and 3 month old gas (Amoco high test). The answer is........ My 2 year old Random CAT was all broken up inside and wasnt converting the gases like it was supposed to. Don't know how it got all broke up? Any ideas? Thanks to Tonys corvette shop in Gaithersburg, MD for doing a fine analysis and fixing what was broke the first time around. :yesnod: :yesnod: :yesnod: :auto: :hurray:
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
The answer is........ My 2 year old Random CAT was all broken up inside and wasnt converting the gases like it was supposed to. Don't know how it got all broke up? Any ideas? Thanks to Tonys corvette shop in Gaithersburg, MD for doing a fine analysis and fixing what was broke the first time around. :yesnod: :yesnod: :yesnod: :auto: :hurray:
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (94lt1torchred)
You may have an answer there. At work they installed these mobile barrier ramps, after 9-11. I do believe I have bottomed out on those things. And with the headers, the CAT is the lowest hanging fruit. :nono: I will have to be more careful, and park across the street, when I drive it to work.
Melting Slicks
Joined: Apr 2002
Posts: 2,620
Likes: 0
From: 20 forward gears to shift through in MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
You may have an answer there. At work they installed these mobile barrier ramps, after 9-11. I do believe I have bottomed out on those things. And with the headers, the CAT is the lowest hanging fruit. :nono: I will have to be more careful, and park across the street, when I drive it to work.
Drifting
Joined: Jul 2002
Posts: 1,488
Likes: 4
From: Frostburg MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (Denney)
We don't have testing out here in the western frontier of MD, at least not yet. Let us know if you find out why your cat broke, I just bought one of them from another forum member and was wondering if there was anything I should watch for.
Race Director
Joined: Aug 2000
Posts: 11,506
Likes: 4
From: Vancouver,Wa.
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
I had the same thing happen to my Random tech. I think the reason why it failed is, It was way to rich to begin with. You and I have almost the same set up with the same injectors and I run my FP at 39 and I pass DEQ with flying colors with out EGR function.
Intermediate
Joined: Sep 2003
Posts: 34
Likes: 0
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
I was going to take my cat off my 87 for a cleanout and when I took it off, it had chunks of the ceramic material in there sideways. I think it is because the position of the cat is in the center so when you go over a speed breaker it hits the cat and that stuff inside is very brittle. :chevy
Thread Starter
Burning Brakes
Joined: Nov 2000
Posts: 1,012
Likes: 1
From: Bowie MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
Just got the old CAT back, and was shown how the honey comb was in small peices that literally fell out when you stood it on end. All that was left was a screen inside in the middle. Tony showed me another on the shop floor just like it, that they had just replaced as well. The heat shield shows no sign of scratches or bottoming out. So the theory of running too rich, is a distinct possiblilty. Iam running at the 47 puonds mark at the moment. I am deathly afraid of the stories of running too lean and burning out the new motor. By the way see my old post where I was worried about this earlier, and it proved true, several months later. http://65.54.172.250/cgi-bin/linkrd?...9%231544305649
[Modified by corvette1990, 3:45 PM 11/8/2003]
[Modified by corvette1990, 3:45 PM 11/8/2003]
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Apr 2002
Posts: 2,620
Likes: 0
From: 20 forward gears to shift through in MD
Re: Passed MD emmissions finally, Guess why it failed, answer inside. (corvette1990)
Chris, seeing that you are in Bowie, give me an e-mail me or IM me and maybe we can get together sometime! I am in Mitchellville, can't be that far away! :cheers: