As the title says, I've just failed an E-Test. Looking for any ideas on how to get by the sniffer.

Of the three criteria measured, I only failed the third, which measures NOx from the exhaust. Possible causes listed are: Faulty EGR System, Malfunctioning Cat, timing, etc... I have a feeling that it's the Cat, as I just installed a Magnaflow Hi-Flow cat. Given, the car has sat for six months, over winter.

Any ideas? I've had people tell me to run some gasline antifreeze at about 1/4 tank, to keep the octane high, and emissions a bit lower. Any other ideas would be welcome.

Mention: I still have all the stock emissions control components on the engine, only run 94 octane, and since it's a '94 I only have one cat.

maybe your tune is to rich???

I have the Flow CATS (OBD2 ones) with no issues.

drive the car for 1/2 hr before smog test...you want that CAT hot.

yeah that's usually the best suggestion. drive it around, then let it sit for a while and heat up. When you show up to the testing facility, do not shut the car off.

i failed with the magnaflow cat.

What was your NOx reading. If that is all you failed, you might want to verify that your EGR system is operating correctly. Make sure you don't have any broken lines to the EGR solenoid and valve. If you have a Miti-vac, you can disconnect the line to the EGR valve and pull a vacuum on it. If the vacuum does not hold, the EGR valve is bad. To check the solenoid, you need to hook the line up going to the EGR valve to a vacuum gauge or your miti-vac and load the vehicle up. It's easier in an auto and help from a friend to read the gauge. No engine load you should have no vacuum(solenoid closed), and with engine load applied you should have manifold vacuum indicating the solenoid is operating correctly. If the solenoid isn't working verify you have power and ground, once again with load applied. I believe the pcm controls the ground circuit to the solenoid. If you have power and ground, then the solenoid is bad. I deleted my EGR setup and AIR system and only use a cat to pass.(normally run an Off-road pipe) I run a small cam though that gives just enough overlap to give an EGR effect without the valve. Hope this helps.

Run Hotter plugs, have fresh oil and make sure your temps are high, This is one of the reasons that from the factory the temps are like 220*. If you have had it programed for a 160 stat, try unplugging one fan, let it idle with the ac on to get it hot. A high idle also helps.....

I don't have the report in front of me, but I know the NOx reading was about 2x the allowable limit. So, limit was roughly 400 units I believe, and I was reading about 800 units.

The troubleshooter guide that the etest facility gave me suggests EGR as a possible issue as well. I just really had no idea on how to test it's functionality. I'll take your advice, and try it out.

Do you have a smog pump on your setup?
Check the EGR compress the valve hold your finger over the nipple where the vacuum hose goes if it decompresses and takes on air its bad.

Yep, thats the easiest way to test the EGR valve.

From my experience, all of the above are good suggestions, heat, fresh oil etc... I failed horribly with my OEM cat, replaced it with the Magnaflow and got the best numbers since the car was new.
If the cat was just put on, I was told to put about 100 miles on it before bringing it in for inspection as well?

I have the Magnaflow cat, when I put it on it passed with flying colors. My car was also sitting for about 6 months as it wouldn't pass emissions(which had to do with the fact the OE cat was gutted) I also didn't really put any miles on it, but I did beat on it the entire way there. Mine was also a special case as it wasn't failing emissions by much, especially NOX, so take that with a grain of salt. Just trying to say a properly running car should pass.