Damon

1992 5.0 TBI camaro. OK, this is not a really fair question becuase the engine has over 190K miles on it. However, it's all stock and runs like a top under all conditions. I mean NO problems at all. No codes, computer diagnostic scans even say that everything is kosher and "sane". It's had a tune up, incuding a fresh O2 sensor, chip is stock, timing set to stock (0* with timing wire disconnected per the emissions sticker) and everything else on the motor is dead stock. I had a new cat installed and it still has emissions readings that are through the roof in all measured areas- Hc, NOx, CO. Frankly, the fresh cat made absolutely no difference. The emissions guys say they're some of the worst readings they've ever seen on any motor, PERIOD.

Fortunately, the new cat was enough money that I get an exemption and pass anyway. But what the heck? This thing should be blowing perfume out the tailpipe. I mean it runs absolutely perfect under all conditions. I can't believe it's that far off.

Is there a typical trouble area for these TBI motors that would send everything through the roof? I have my doubts about the EGR valve but I really can't beleive that it could cause things to be so far out of whack.

swerve-driver

Thats pretty weird-
A few questions-
Was the engine/cat at proper operating temp prior to/during testing?
Hydros:
Is the AIR tube to the cat hooked up?
Is the AIR pump running (pumping air to exhaust manifolds and cat).
Is compression on all 8 cylinders to spec or at least reasonable?
(Is the motor using oil)?
Old gas?

Nox
Could be a faulty EGR valve or carbon clogged port.

CO
I'm not sure what would be giving you grief here.

I've never heard of an AIR pump conking out, but I suppose if it wasn't pumping air into the exhaust manifolds and cat to complete combustion and increase cat temp, it could allow for high Hydro readings.

Or could be a test station screw up. I went in for a voluntary test and found that they used a different tred mill setting on two different tests for the same car.

S-D

What were the actual v acceptable readings?
Tread mill or idle test?

Dewey316

i assume the rest of the countrys equipment is about on par with the stuff here in OR, but when i did it, i went in and failed, failed HC's and NOX badly. drove imediatly back in line, next run through i was on a diffrent machine. this time HC's and NOX were almost minimal, but my CO count was through the roof, and i failed again. i think alot of testing is just dumb luck, as i have seen absolutly no consistancy in any DEQ testing.

Z28GEN3

thats funny you say that. most of the idiots at the testing places wouldnt know ther @$$ from a hole in the ground. and testing does or sometimes depends on who is operating the equipt.
ive heard some stories that they failed some cars(with a 4spd) out here becuase they could never get it into 5th gear LOL
At least in Az i was told to remove the stickers in the engine bay dont give those morons any hints or make it ez for them. thier job is to ez as it is. and yea it is dumbluck we was told that our truck needed a new cat umm BS the next day we ran it threw and passed.

357mag

AZphreak,
Roger that on the morons at the smog stations. Took my 94 C1500 w/5 speed. (granny low, 1-3, then OD) they tried to start in L (6:1 ratio) then wound the tranny so tight, they couldn't get it into 1st gear. Thought I was gonna hafta whup up on the dope behind the wheel. Anyway, I passed the sniffer, but the SOB's broke my vacuum line on the charcoal canister, failed the equipment part of the test, made me get the truck tested again. their only response was " state law says you have to get the whole test done again" What a crock! By the way, the station I used was the one in Glendale, near the airport.
Tim sends

bbtaz97

iTrader: (3)

could the smog pump be locked up?? happened once before... all i did to pass here in IL dyno test is put on and 3 inch cat that matches the rest fo my exhaust and stock chip and fix the the tube that runs fromm smog pump to cat... and then i passed by alot . try amaco gas and run some good fuel system cleaner as well.. ..

check air filter as well..

91rs4life

I second that notion. Here in Il they love to beat your crap. I was told I couldn't test because I was leaking oil. I put in a new oil sending unit and my 79 5.7 SBC ( I had it in a 79 buick lesabre ) passed. I basically did this:
ran a 2.5 y pipe to a fork. The fork inlet was 2.5 the fork outlets were 2. I put 2 cats on after the fork. I couldn't squeeze them in next to each other so (towrds the drivers side) I went from fork to cat into an extension and had some pipe custom bent from there, into the stock tailpipe that they used on the buick wildcats for the drivers side tailpipe. (towards the passenger side) I put a extension next to the cat mentioned above and then put a cat after that (next to the extension above). from there I basically used straight pipe to go to the other tailpipe and popped right out of the back end.