HELP - FAILED CA SMOG "TEST ONLY"

[PENNEYTOM]

ook my car in today for it's biennual inspection and it failed. It passed on everything except the CO% - reading too rich for them:

Maximum allowed at the 15 MPH read is 1.36, mine was 2.34
Maximum allowed at the 25 MPH read is 1.16, mine was 1.78

The tester just said to lean up the carb, as the car passed well within range on everything as else (HC, NO%) as well as passed the visual and functional stuff. Here is where the stupid question comes in, to lean up, do I turn the mixture counter clockwise or clockwise? Could "over leaning", other than cause the car to run crappy, cause a test failure? I recall leaning up another car years ago to pass the smog test, but that was before the new CA test.

Absent doing it myself, I'm faced with taking it to a mechanic that does not know Fiats OR get real creative with Photo Shop and create a couple of CA temporary pink window stickers. Thanks for any help.

Tom

[scarlson]

Turning the idle mixture screw clockwise leans the mixture out.

What carb do you have? The starting point for the stock 32 ADFA (pre 78 1800) is two turns out. I'm not sure if the ADHA(79 2000) is different but is not likely. Turn the screw all the way in counting how many turns. It should be within a half turn of the starting point if everything is working ok. Let us know what you find.

If you lean it out too far, the hydrocarbon emissions will go up due to incomplete combustion. That and the car will run horrible

[So Cal Mark]

leaning the idle mixture won't really help with the readings at speed. It is possible to get a lean misfire with high hc readings. Make sure your air pump is working and that the air injection rail isn't plugged with carbon. If that system is working, you're going to need smaller jets

[PENNEYTOM]

Thanks. The car is a 76 with the carb you described. I had replaced the air pump recently and checked the injection rail - it did not appear to be clogged or anything- in fact it looked pretty clean. It took about two and a half turns from where it was set to get the it where the car was skipping and idling poorly (too lean) then I backed it off just to a point where the idle speed increased and smoothed out, which was about 1 turn from the too lean part. Not sure if this will help it pass, but it starts and idles smooth at this setting. Not sure if I should try it this way for the freebie retest. Is there someone in the San Gabriel CA area knowledgable with getting these things to pass?

[jimincalif]

Our moderator So Cal Mark is in Upland, just down the 10 a bit from San Gabriel.

[So Cal Mark]

I'm not very far from SGV. Leaning the idle mix may decrease CO .1 if you're lucky at 15mph and less at 25mph

[PENNEYTOM]

Mark- thanks. The readings were worse at the 15 MPH, but not as bad as the 25 MPH. I'll probably take a chance and go for the retest. For info, the other readings were for the HC, MAx allowed at 15 mph 214, mine was 70, for the 25 mph, max allowed is 181, mine was 54, for the NO%, max at 15 mph 1364, mine was 216 and max 1224 at 25 mph, mine was 244. Anything else you can think of I can try before I take it in again?

[So Cal Mark]

those readings are pretty good. I'd look down the top of the carb at the air jets. If the secondary is larger than the primary, swap them for the test. Otherwise you'll need to change the low speed jet to a smaller size

[PENNEYTOM]

Mark - The jets on both appear to be the same, but hard to tell as not sure how much of a difference can be seen, so I changed out anyway and adjusted the mixture and idle. If new smaller jets are needed where can I get them and what size or diameter? Of course, after running the car today, I shut off the engine, and now electrical completely dead. Is this the thrill of Italian car ownership?

[So Cal Mark]

the air jets should have a number stamped on the top that you can read just by looking down the carb. If they are the same, you'll need either a larger air jet or smaller low speed jet. As for sizes, you will have to determine what is in there now

[PENNEYTOM]

Mark and anyone else who can help-

The air jets are marked 180 (primary) , 170 secondary) and the main jets in the fuel bowl - 125 (primary) 140 (secondary)- the car failed on both CO% at 15 mph and 25 mph (but not as high)

You mentioned swapping the air jets or re-jetting to a smaller low speed jet - Now dumb question #2 - which or where is the low speed jet?

[So Cal Mark]

the low speed jet is on the end of the idle cutoff solenoid. Use 1 size smaller than what you have in there now or use either a 190 or 200 air jet

[PENNEYTOM]

Thanks- now any source recommendations for where to get the jets?

[So Cal Mark]

Redline is on the westside, Pierce Manifolds is on the web

[Fonz]

I was under the impression that cars 30 years plus were smog exempt.