[hmacris]

OK so the car is back on the road, with the new suspension and everything, it feels great!

BUT- its keeps failing emissions here in CT.

Yesterday it tested over for HC an CO but not NOX-

HC was 144 and limit is 100 and CO was .64 and limit is .53.

So i took it out last night, drove the pants off it, put in 2 gallons of premium. Then drove again this morning, fast and hard on the highway, put some octane boost in and then ran hot over to the testing- left it idling while waiting and tested it again.

Today

HC was 134 and CO was still .64.

What to do now?

 

[Gubi]

Any idea how many miles are on the oxygen sensor? In my experience they start reading slow around 60K and can be pretty knackered by 90K.

 

[hmacris]

New O2 sensor with engine rebuild, so less than 6K miles...

 

[Del]

Could be, although my 91S has never failed a smog check (actually, none of my Alfas through the years) even with 150k miles on it and the original O2 sensor (I've now finally put in a new one, just for yucks).

I always throw in a set of new plugs (I always use the best NGK plugs), or at least clean the ones in there, clean the dist, frequently use FI cleaner Techron, and of course dedicated "Italian tuneup's" a couple of times several days before the scheduled check. I've always used premium in the car, since we have hills here in Seattle, and the engine will ping or whatever if not. No knock sensors in that car.

 

[Ted 168]

the dreaded emission test

I know so many people who have trouble passing the emission test, especially the NOX limits. Some are brainstorming about ideas to cheat the system. One idea is to run the car on methanol for the test which will pretty much give zero emission. I think this is workable. ideas?

 

[Del]

Funny, I've never had a problem with any of my many Alfas which have been required to go through a smog check. I know Washington State doesn't have the most stringent requirements, but they are not the easiest either. Usually, the tester shows me the test results that show that, essentially, the car didn't register anything of consequence, he shaking his head, mumbling something about it being one of the cleanest cars he's seen. Just lucky I guess.

 

[hmacris]

Apparently those numbers point to unburned fuel leaving the engine.

Could those cheapo plugs I put in during my rebuild troubleshooting be the case? I have some slightly used NGK Iridiums I could throw back in, maybe get a new air filter too?

Any thoughts? The guys there just said throw some dry gas in there...

 

[ChazzyD]

My car runs beautifully with "cheapo" Champions 415s and passes emissions tests with ease. Define what your "cheapo" plugs are exactly or we are only guessing. I have spent money on expensive plugs in cars before that simply did not work for the car I was working on, you can NOT equate money spent = plugs that will solve your running problems just because they are expensive or fancy (read - heavily marketed). Air filters don't solve E test problems, unless they are really badly clogged up, no matter how much the auto parts store wants to sell you a new one, it likely isn't going to be the real problem.
Charles

 

[Del]

It may be true that some expensive plugs will not work for any given car, but good plugs CAN make the difference. As an example, Bosch Plus 4's won't work in a 164S, but the NGK Iridiums are excellent. I like to think that new good plugs can make the difference between passing and not.

 

[ramzromeo]

I had trouble passing my 91 164L here late last year. I put a new CARB compliant cat in it and it was still high in NOx at the higher run speed of 25 mph on the dyno. I put on new NGX iridiums and ran the tank down to less than 1/4 tank of premium and added a bottle of stabil. The guy tested the car and it passed. Upon looking at the results I noticed that he ran the car at higher RPM (2400 or so) at the 25mph than the previous shops that tested it. The NOx dropped big time. I guess that the previous shops ran my car in second at lower RPM and may have been lugging it under the dyno load. Not really sure but at least I have data now to compare when I go to next years test.
Make sure you are near a gas station or have some fresh premium to fill the tank after the test so that you are not running on the stabil alcohol.

Oh by the way, my engine has about 14K on a rebuild.

Dave