Last year I made a similar thread about passing emissions with an MS, and how i was pulling my hair out because I couldn't get it to pass. Turns out that my 95's old motor was burning a lot of oil, I rebuilt it with forged internals and 84mm 9.5:1 pistons, and on the same tune it did way better.
First try (old motor)
HC 3.21/0.80 FAIL (4x the limit)
CO 51.69/12.00 FAIL (4x the limit)
NOX 1.69/2.00 PASS

First attempt on new motor
HC 1.53/0.80 FAIL (less than 2x the limit)
CO 20.37/12.00 FAIL (less than 2x the limit)
NOX 1.63/2.00 PASS

The new motor made a huge difference, and after some fiddling around with info from the previous post and around the internet I just tested at this.
HC 0.81/0.80 FAIL (BRUH)
CO 10.91/12.00 PASS
NOX 1.64/2.00 PASS

So close. What should I change in the tune, or should I just throw something like rubbing alcohol (or a different non gasoline liquid) in tank? I attached my tune file, and I know it is incredibly crude, my wideband doesn't work, so I have to basically just guess what's going on, and make adjustments.

 

Try the attached. Timing was a bit advanced, target idle RPM was a bit high, afr was a bit rich, and EGO wasn't active.

Get the car hot, and make sure your EGO correction at idle is around 98-99%. Select a ~4x4 area around the cell you're idling at, and multiply it up/down until EGO is 99-98%.

Also make sure it's idling at 950rpm, your idle duty should be around 34%, if it's higher than that, close the bypass screw, if lower, open it.

 

Slight problem, that I completely forgot to mention... my wideband doesn't work. When I first got the car tuned, the wideband wasn't working so they tuned it without using it, if they told me that it wasn't working, I would have gladly paid them to make it work, but they just used the wideband on the dyno, then told me about it after it was already done. So i've just been doing adjustment for emissions through a combo of knowing what makes what gas go up/down, and pure guesswork, and that almost got me to pass. I'll definitely adjust the idle like you said. And i also tried just pulling timing and it didn't work, it did way worse (1.75HC, 13.59CO, and 1.65NOX), but that could have just been because the car was heat soaked after doing what is essentially 3 hours worth of dyno runs. Maybe just trying again when the car isn't super heat soaked might work, doing the idle adjustment like you said, and/or taking out just a smidge of fuel... or just throwing rubbing alcohol in the tank, which I really don't want to do.

 

Ah, you need to fix your wideband then.

 

I've tried. i've replaced the sensor 2x, the UEGO gauge, the harness in between the two, I've smoke tested my exhaust to find leaks, rewired it 3x and spent hours poking around with a multimeter and an oscilloscope to make sure I did it right. I dont if im unlucky and AEM keeps sending me bad parts, but at this point i'm just going to make it someone else's problem, and have the speed shop I go to handle it, when I get retuned next month.

 

My AEM 30-0300 wideband controller is pretty hard on o2 sensors, I have busted maybe three of them in the two years since I installed it.
I believe that leaving the car systems on, and therefore heating the sensor while the engine is off and still cold, is the cause of my issues.
I try to avoid leaving the key "on" (the click after accessory mode) before a cold start for too long nowadays, I haven't had a sensor fail in over a year.
I'm looking at upgrading to a Spartan3 sometime soon, I like the idea of o2 sensor heat being delayed until an RPM signal is detected.

 

CA smog technician here.

I trust Curly's post/tune should fix your issues. For sure you gotta get the wideband working. Has it never worked at all or are you killing sensors? In reference to evilking's post, putting my wideband on a switch and waiting ~15 seconds after a cold start to turn it on, especially on cold/wet mornings fixed my issue with killing Bosch wideband sensors.

Another point in reference to the smog test, does your car have a PCV-type breather setup or are your breathers vent to atmosphere? Given the motor is new, I'd assume there's minimal carbon buildup on the internals. If you're running a standard breather system with a PCV valve, though, PCV deposits in your intake manifold can drive up HC and CO values as well.

My current '95 was originally a coworker's car, and I did the smog test on it when he first inherited it. It was bone stock and had been sitting outside for about three years. Failed miserably on HC and CO. I ended up taking a look inside the intake manifold and it was coated in PCV/carbon deposits. Ran a couple cans of throttle body/intake cleaner through it (the kind that have you spray 'em into a vacuum port with the engine running), took it for a quick drive to clear out the exhaust, and it went from 2 or 3 times the HC and CO limits to well under them. Passed no problem.

At one hundredth over the limit of HC, there's no doubt you should be able to tune it out, but figured I'd dump this info here for future reference in case it could help anyone.

 

If you wire it to a relay, you can also have the ECU trigger the wideband to power up, using conditions like clt temp or engine run time.

+1 on my own comment to fix the wideband, that needs to happen.

Do you have a X-series aem wideband? You can identify it as an X-series by the two buttons on the gauge face. If it's the standard UEGO, I haven't installed a good one in years, they all seem to crap out super quickly. Get a X-series or 14 point 7 spartan.

 

That's genius, I might just have to save some money and do it! Not like I'm hurting for outputs with a stock BPZE. I like having a gauge to read, anyway.

 

30-0300 = X-series
*edit *nvm that post wasn't from OP

Dunno what I'm doing "right" but I've had my 30-300 with the original Bosch sensor since 2018, it's in the 2nd NA currently.~80.000km of use.
No winter driving though and naturally aspirated.

 

The wideband never worked in the first place, at this point ill probably switch to an innovate or spartan wideband. And I do use a standard pcv setup so my intake manifold is filled with all sorts of crap, ill try cleaning it out with some brake clean and see if that helps, at worst it wont hurt anything.

its a standard UEGO, its never worked at all, so for the longest time I was just convinced that I installed it wrong, but after what people are saying here, some more research I did, and personal experience, I've realized that its just junk, ill probably have it switched out for a different brand and/or model.