I am a GROSS POLLUTER and I don't wanna

[JPL]

So I had my smog check due this year so I went to get it tested. I have the Mark-D chip in it during the test which worried me a little and then sure enough the results.

In the "NO (PPM)" section where max is 767 and 706 I scored a frickin 2860 and 2749.

So my question is if I switch to the stock ECU without the enhanced chip will it make enough of a difference to get me under the max? Or do I need a new cat?

[Todd Black 88]

Not super familiar with ca smog testing, but was that section for hydrocarbons or NOX? Either way you probably need a new cat. Magnaflow has one for like $80 thats works pretty well.

[dark89e30]

You should be able to pass smog with your chip. But if you think the timing may be advanced too much, dump in some 100octane or methanol. Thats really high though, and I can guarantee you need a new cat. Put in some W8LCR plugs gapped to 036 and make sure you don't have any vacuum leaks. You are so far out though, you prob have more issues but start with those 3. oh and no shitty gas. Only cheveron, 76 and maybe shell.

[StereoInstaller1]

Chevron, rubbing alcohol, and fresh oil change...but yeah, you need a new cat.

[JPL]

here's a head scratcher.

went to the test only smog place and adjusted the afm to make the mixture richer while it was getting smogged.

I had to beat 760 in (NO)

I scored a 200. I went from 2600 all the way down to 200 just by making it richer.

I have thought about this quite hard. I made my engine very hot the first time as directed. the second time i didn't at all. Maybe the carbon build up inside the engine doesn't start fucking things up until its really hot but maybe it wasn't hot enough to make the old shitty oem cat work properly so when i tested it the first time i was in a dead zone where my engine was spitting out bad exhaust and the cat wasn't hot enough to burn it yet. other than that I have no fucking idea what happened to cause such a change.

Richening the mixture should not make that big of a difference. Unless it does. which it did. my car is an enigma

[Wolfsburg]

If I understand...

High combustion temps=high NOx output

Add fuel (fatten the mixture) and combustion temps will drop, lowering the NOx level.

If over the years, carbon deposits have built up in the chamber, then your CR has gone up a bit, and so will the chamber temps.

EGR systems are used to control NOx levels--the inert gas recirculation lowers combustion temps (without the increase of HC a fatting-up of mixture can see).

[netcsk]

You're looking at it a bit from the wrong direction. You're right, but:
Lean Mixture = High NOx
If there is not enough fuel to fully use all of the oxidizer (air), then the high heat will cause air (Oxygen and Nitrogen mainly) to combine to form various forms of Oxygen and Nitrogen. It forms NO mainly, with other forms as well - hence NOx, with the x being various number.

In actual conditions, the exact perfect mixture is the hottest an engine will ever run. In a car, the engine is actually designed to run slightly rich. This means that when it leans out a little, then the engine runs hotter (actually running more efficient as well), which gives you pre-ignition yada yada. Blah blah blah. Just wanted to give a little explanation.

[cferb]

I passed easy with my Mark D

[Nicademus]

I just passed emissions in Seattle with a gaping hole in my cat and an engine with 234,000miles on it, but California blows and has wacked out standards. I advise moving out of Commi-fornia.