Time for a smog check

[Steve87GN]

Well, after a couple years in retirement, I brought the mean "little" one back to the streets . Before the month is out, I need to get a smog check. She's never failed a check before, but I'm wondering what things I can do to make sure she passes with flying colors this time. Here's what I've done so far...

New vacuum block and gasket (old one actually broke on removal, go figure; part needed for vacuum brake conversion)
New K&N stock air filter
New Bosch platinum spark plugs (O.E. heat range, etc.)

...,still need to do...

Oil change (going to Royal Purple w/ K&N oil filter)
Fuel filter (picked up a Fram unit at Kragen, should be good, right?)
New wastegate solenoid filter

...and am wondering about...

New oxygen sensor - how long would it take the ECM to recal. to the new sensor, since it would more-than-likely be more responsive than the current one I would imagine?
Convert to heated oxygen sensor - would this cause me to fail the visual on a CA smog check?
Anything else I'm missing or could do?

Thanks as always

[tom h]

from description posted on your website My 1987 Buick Grand National ,
the valve cover breathers will definitely fail visual in CA ... you need to revert to stock setup, to pass.

and by "K&N stock air filter", do you mean a K&N replacement in the stock air box? -- which should not be a problem. If it's the large, external K&N cone filter, it will likely fail visual unless K&N has a Calif CARB exemption or "exective order" (I think).

[SouthernCal GN]

Correct on the EO #: when the tech lifts the hood, anything not factory that does not have a CARB EO# (air filter, breathers, AFPR, electronics, etc) is grounds for failure. As these cars are 20 years old, you may get lucky and get a clueless tech that will just glance under the hood.....

On the test itself, I just passed the WA State emissions test- used a TT emissions chip, and turned the fuel pressure way down. Passed without a problem....

[Steve87GN]

Originally Posted by tom h

from description posted on your website My 1987 Buick Grand National ,
the valve cover breathers will definitely fail visual in CA ... you need to revert to stock setup, to pass.

and by "K&N stock air filter", do you mean a K&N replacement in the stock air box? -- which should not be a problem. If it's the large, external K&N cone filter, it will likely fail visual unless K&N has a Calif CARB exemption or "exective order" (I think).

Already have the stock covers on, but thanks for pointing that out . Also, it is a the K&N replacement filter in the stock airbox, so I don't imagine that would be a problem.

Originally Posted by SouthernCal GN

Correct on the EO #: when the tech lifts the hood, anything not factory that does not have a CARB EO# (air filter, breathers, AFPR, electronics, etc) is grounds for failure. As these cars are 20 years old, you may get lucky and get a clueless tech that will just glance under the hood.....

On the test itself, I just passed the WA State emissions test- used a TT emissions chip, and turned the fuel pressure way down. Passed without a problem....

I actually have yet to really see a smog tech that knows what these cars are to begin with. I actually had one ask me, point blank, "Is that supercharger legal?" lol

The only thing I'd be really concerned with is if I put the heated 02 conversion kit on from Kirban.

[SouthernCal GN]

Shouldn't be a problem...the heated O2 mounts in the stock location, and uses weatherpak connectors.......looks factory.

[Steve87GN]

That's what I was thinking. Would swapping the O2 at this point hurt my chances of passing till the ECM recalibrates? Should I wait on touching the O2, conversion or not?

[SouthernCal GN]

Here's what I would do: make your changes, then take the car on a drive long eough to get the convertor nice and hot. The car's calibrations should be just fine.

FWIW, when I did my check, I made the changes right in the parking lot. See this thread:

TT Emissions chip

Note how the HC and the CO dropped like a stone....

Stay away from the plat plugs....many have had problems with them. Stick with AC. Make sure all your vac lines are OK.

Which chip are you running, and have you done any mods?

[Steve87GN]

My dad says the local dealership installed a GNX chip after having problems with the car dying. I'm not sure about that, but it wouldn't surprise me if its stock. Its relatively stock as it sits.

[SouthernCal GN]

Get the numbers off of the injectors and the chip and post them. That'll help identify what you have.

Hhow does the car run?

[Steve87GN]

She runs like a champ, esp. after taking off ths Slugmaster. Hardly any irregular idle on cold start, fires up every time, runs strong. I'm not anticipating any problems, just want to make sure she's it tip-top shape, know what I mean?

[Steve87GN]

Ok, I'm going in for my smog check probably on Fri. I'd like to replace the O2, but am not sure which one to get. AC Delco lists 2 different ones, AFS20 and AFS21 (which is the same sensor that my 93 Z28 uses). Which one should I pick up? Or does it really matter?

I'll check the #'s on the injectors and PCM tomorrow and get back to you guys. Thanks again for all your help

[SouthernCal GN]

Just go to your local GM dealer, and get the factory O2 sensor (purple wire) Don't remember the part #, but it works just fine....

[tom h]

My information is that the stock 87 GN O2 sensor is:

GM # 25162693

also goes by AFS-20 and AC-Delco # 213-503

[Steve87GN]

Very good, thanks Tom. There's a local AC-Delco shop nearby, I'll swing by there and grab one

[Steve87GN]

Well, took her in today. After some garbage about having to take it to a test-only station instead of any smog station like the paper says, got her tested. Here's the results...

Speed - 15 MPH / 25 MPH
CO2 - 14.7 / 14.7
O2 - 0.2 / 0.1
HC Max - 110 / 85
HC Mes - 4 / 50
CO Max - 0.71 / 0.59
CO Mes - 0.00 / 0.04
NO Max - 772 / 711
NO Mes - 124 / 208

Needless to say, she passed . And pretty well I think. Anything I need to be aware of from these results? Or am I lookin' good? Thanks guys.