Doug in Texas

My 94 LT1 failed the new Harris County Emissions test. It's performed on a dyno at 15 and 25mph. I was high in HC 269/267ppm vs 120ppm limit, CO -just barely over the 0.65% limit, and NOx 1625/1390 vs a 900ppm limit.

The car has a new long block, new wires, distributor, and plugs. It runs great and idles smooth. The O2 readings were steady at 8.0% so I assume the O2 sensor, etc., is working ok.

The test station is near my house, so the car wasn't that warmed up. If I threw in some 104 octane booster or soemthing like that and warmed it up real good, do you think it would pass?

1bad85

that sux man, mines up for inspection now too. BTW I live in harris county too, which part do you live in? Maybe we can get together and swap some c4 talk.

B84RADR

Get that sucker as warm as comfortably possible. Also you might try to run some of the Emissions Pass stuff. They sell it on the shelf here in Utah at Checker, AutoZone, Pep Boys. You get a full tank of gas, put this stuff in there, run it till it's almost dry, get it real hot, fill it up again, and take it right in to the emissions testing place. I almost halved my levels of emissions this way. Hope it works for you too.

StarShipCmdr

We don't have dynos here - they just stick the probe in the exhaust. When I've had trouble in the past (not with the Vette, thankfully) I've found that 4 - 6 cans of Dry Gas works miracles (hope you can find it in Texas). It really helps to have it good and hot! - deep hot, like after 20 miles. If the lanes are close, take the LONG way. Good luck.

Ray

Steel Blue 91

When I lived in NJ (another life) we would run the tank almost dry, add about a quart of alcohol (denatured), fill it up to a half tank and drive straight to the inspection station. All my cars passed the first time. Haven't tried it in a vette (injected), but it worked on carbs.

BrianCunningham

If you have a lower temp stat, this will here.

Let it idle till it gets up to temp

One of the reasons GM runs the cars hot from the factory is emissions.
The alcohol/dry gas tip is a good one.
You can get it at Autozone etc. they can order it if it's not stocked down there.

trupp

Hey Doug,

I can feel for you. I've just finished my ZZ4 install on my 85 and am breaking it before visiting the emissions test. I concur with the other readers try the alcohol and have the car hot when you go to the testing facility. By the way I live in Friendswood too. Which inspection facility are you taking it to?

his touch

Move to Iowa Colony. No emission test until next March. My vehicles will be inspected in Feb whether or not they need it. I thought they could hook it up to the computer instead of the dyno.

When I hac mine inspected in Alvin yesterday, the shop said they were going to get the dyno next year. I will quote "The money is in the repairs, not the testing." Makes you wonder if they wor at making you pass.

Can you go to another shop and pay them to check your levels before they do the actual test. I know you used to be able to, but not sure if that is an option with the new equipment. If you go in for a test and fail, youwill be labeled as a gross poluter. OFF TO JAIL WITH YOU, YOU BAD BOY.

Ron, just a few miles south of you.

tkrussell

You might also want to check your cats. Cats will deteriorate with age, although I have not seen a graph of the loss of efficiency.

The test is done at part throttle on a warm engine-- this is closed loop territory for the engine, so it should pass easily if EGR is still connected and the ignition and injectors are good. Also, check your Air Filter and MAF for cleanliness.
Any ignition glitch or dirty injector will rapidly send the HC emissions skyward. The NOx will be high if you have blocked the EGR.

vert2go89

like above said run the tank way down and then add colemans lantern fuel to the tank.then fill tank about half and take test.I've seen this work many times.colemans is very high octane and burns clean.