quinnfiske

I got my car to pass in Wisconsin (IM240 dyno test, probably like NY) by replacing the O2 sensor and adjusting the CO level at the AFM. I think someone adjusted it at a prior time with an inaccurate sensor and the new one screwed up the mixture.

Chris White

Keep in mind that the O2 sensor is measuring the average of the 4 cylinders - if you have a partialy blocked injector the DME will add fuel to all cylinders to bring the average mixture back to normal - then you will have 3 rich and 1 lean cylinder - the gas analyser will see this, the O2 snesor will not.

markdk

Putnam County (the first county north of Westchester) is the first county where emissions isn't required. But as a prior post says, where the car is registered is what dictates (I know this from first hand experience).

Techno Duck

I called the guy who did the inspection and he said the car was run about 30 minutes prior to the actual test. I have no real reason to doubt him.

Just checked the CO adjustment on the AFM. Its definetley been adjusted at some point because the plug is missing. So i am going to install a new O2 sensor and attempt to adjust it back to normal specs. I am going to try and take the car to my friends shop which has a emissions machine so i can utilize the 3-gas sensor to get it set right as per the directions in the factory manual. I thought that CO adjustment was only for idle.. does that affect the #'s across the board at partial and wide open throttle?

Lets see, possible mal-adjusted AFM, possible bad injector and bad FPR...i think this is a sign to upgrade to the Vitesse MAF, 55# injectors and 3.0 bar FPR... .

rlm328

When I originally tried to have my car inspected the readings were through the roof. I bought some of the fuel additives they have at Autozone, O"reilly's, etc, for older cars to help clean up the injectors and all the other stuff. It cut my emmissions about in half. But having said that it sounds like you have something mis adjusted. I don't know about NY but in Texas, once your car goes into the computer your doomed as far as the type of test you have to take.

Cory9584

Maybe because your using stock chips on a modified car? Otherwise find somebody to pay off

quinnfiske

While the AFM adjustment is for idle, it adds air to the system at all air flow rates so it has some effect at larger throttle openings. I was failing by a slim margin, so maybe it would not have an effect for gross failures. It did the trick for me however.

Make sure the car is warm. Letting it cool for 30 min for the test is not good. Take it out and drive briskly for a while to heat up the catalyst and test it immediately.

Papamurphdog

You need a CAT dude. I added a Fabspeed race cat and it went from off the charts to barley regestering in all categories; and I still run it a bit rich! Buy a cat, run it hard to heat it up and you'll pass inspection.

Techno Duck

The car has a cat on it.. and having a cat or not will not change my CO and HC #'s, only NOx.

marky522

Incorrect, you dont rely on the CAT to get your numbers down, it can only do so much, I have heard of the 944 series passing without a cat. And he is running rich, because the HC and CO are both high, that suggests that all the 02 is being used up and there isnt enough 02 to create C02.

See above, you shouldnt have to rely on your CAT to pass.





These are 3 way CAT's so they reduce HC, CO and NOx. High NOx suggests that the combustion chanber temps are getting higher than they should, which actually contradicts your car being rich, cause a rich micture should burn cooler.

Mark

Papamurphdog

Yes, the CAT is a 3 way. Also correct that LEAN is actually more of a problem in emissions than rich. Assuming the car is tuned, can be slightly to the rich side, it should pass if cat is working. Otherwise I would go for the CAT (and perhaps the O2 sensor just for yucks) and see what happens. I moved from NJ to GA and both my "86T and '90 944 cab, were not even close to passing; numbers off the charts. Put the fabspeed CAT on the ''86 and it barely registered and emissions at all, while still fairly rich. The '90 got the Random Tech CAT and I disovered that it was actually too lean. Adjusted the mixture two clicks rich and it not only ran better but it also barley registered any emissions at all. This is not conjecture, its what I did to pass. The '86 had no cat and was not close to passing in NJ or GA. With no cat I'd be afraid to tune it to pass and then track the car. I bet no way it pases with no cat in NY, NJ or GA. My two cents...

Papamurphdog

BTW, the old cat on the '90 was proven worn out from age. I went 3" on the '86 and ditched the cat long ago, but a "friend" helped me get a sticker. No such luck in GA. $10,000 fine to the shop if they issue a sticker without the paperwork.

Scootin159

If the car's gotta pass the sniffer test in NY, it's hard to get a 'friend' to pass it. Stickers are issued to the licensed mechanic, not the shop, so he is personally responsible for what happens to them. On top of that, the sniffers are plugged right into the DMV's computer system... so theoretically they can look up the exact test results by scanning the barcode on the sticker.

Of course... how would they know if an new Honda Civic was sitting on the dyno when the test was run....

Techno Duck

There is a camera that is watching the dyno..thats how they know. I dont think anyone actually checks it though. What they usually wont see is the car with the sniffer in the tail pipe behind it or the dyno being unloaded prior to testing.

Picked up a new universal 3-wire O2 sensor this morning.. going to install it either today or tomorrow. Ill then adjust the CO screw on the AFM using a voltmeter. Monday i just need to decide to have it retested or have it 'retested' if you get my drift. Sometime next week when a few checks clear ill also be ordering a MAF to replace all the AFM nonsense...

Techno Duck

Did some testing on my AFM and i have a feeling the CO adjustment is way outta whack. I am curious, what AFR should i get if i disconnect the O2 sensor when the car is running.. does around 11.5 AFR sound right?