Failed Smog in MA

[Monza_dh]

My '88 stock 3.2 with 98K Just failed my smog test. I've searched and it seems most posts are in Ca which has a slightly different test. Mine passed the HC and NOx but failed the CO. The numbers aren't bad:

HC: .92 Limit: 2.00
CO: 32.03 Limit: 30.00
NOx:.18 Limit: 3.00
CO2: 377 N/A

I just had a major engine overhaul including valves and put in new plugs etc as well. My CAT is original as is my DME and exhaust.

I've read many posts and before I buy a new sensor or CAT I am wondering what other options I have?

I ran it about 1/2 hr before the test which may be the problem.

This is one post:
"A high CO level can result from a bad fuel pressure regulator, a bad air flow meter or air mass sensor, a bad performance chip, a bad temperature sensor, or a bad O2 (oxygen) sensor"


Any other thoughts? Run it for more and try again? I have 60 days to go again.

thanks

[Jeff]

Dave, I'm not sure how they test in MA (whether it is just idle or a full dyno test), but you can lean out your idle using a 3mm allen wrench on the port on the bottom of your Air Flow Meter. Counter clockwise leans it.
Definately get the car hot. The hotter the better, and leave it running until it is your turn. If the cat is the original one that may be your culprit. The same could be said for your O2 sensor.
I have heard that if you unplug the electrical input to one of the fuel injectors that cylinder will act as an air pump and add "fresh" air to the mix helping you pass.
If you use any of the above methods to manipulate your output, return it to normal ASAP.
You aren't off by much. Do you know anyone with an extra cat in your area? Will the state let you test multiple times for free?

[klaucke]

It is a dyno test normally. I would add some gas dryer (it has lots of ethanol) which burns very cleanly. Get the car nice and warm before the test. Also, see if you can convince the station attendent to do a two-speed idle test instead of putting it on the dyno-- no load on the engine can really make a difference. It can be very hard for some testers to keep the car within the specified speeds while driving a 5 speed, last time the attendent even ground some gears on my car.

Also, as Jeff suggested you can lean it out a tad on the DME. You get the retest for free, but if you fail that you have to pay again, but once you finally pass the sticker is from the month you first failed, so it's worth it to just get this stuff out of the way.

[petrolblue83911]

-Where in MA are you?

Not that I'm into violating any laws, but I know a few stations that should be able to get you a sticker... One is in Weston, the other is in Framingham.

-If you want names PM me

-Adam

[PSJoyce]

Not really wanting to hijack this thread…

The quality of work done during the Mass inspections does seem to vary. I sold my 1988 911 after the gas station that had been inspecting my cars left big scratches on the sides of my 911 from the straps that held it onto the then brand new dyno system. (Traded the 911 for an A4 quattro that couldn’t be put up on the dyno).

This time, with the new car, I checked with my mechanic for an inspection station that “wouldn’t destroy the car”. He understood, and sent me to another shop, likely a competitor of his, where the tech knew how to work a manual transmission. This time, things went just fine.

Not sure if a database would be overkill, but even based on my limited experience, there are places I’d go for an inspection, and places I wouldn’t.

Paul

[Monza_dh]

Thanks guys. I know the station owner pretty well and we talked about a few options when I take it back. He was tied up at the time so one of his emplyees did the test. I'll talkt to him about the idle test and leaning it out a bit.

I also read that if you tell the guy to stay in 2nd you may have a better chance. I plan to get it real hot and try again in a few.

Its a real pain but no rush since I have 60 days and the winter is coming.

Adam, I'll PM you since I may need an "in" the next time around!

Thanks for all the input!

[anh911]

best, simplest first step, assuming that everything is in good order, would be to change the setting at the dme. you're not that far off and given the new rebuild it might be needed anyway.

[HarryD]

This chart shows how your mixture affects the different polluntants



If you lean the car out a bit,you will raise you NOx and HCs a bit but your CO will drop into range. Hopefully the trade off will work for you.

[anh911]

Just found the link to the details on the "fuel quality switch" in the dme.

http://www.911chips.com/fuelsys.html