1981 Spider California Catalytic Converter

[Calman]

My car has a v hard time passing California SMOG with it exceeding the the NOX reading. The current cat Converter is a 2015 as part of a full beautiful exhaust system from Allison's Automotive (which has since closed). I've had trouble passing SMOG ever since.

Any recommendations for which California legal Cat converter to fit for my 1981 Spider? It doesn't have to be the 4-bolt flange version.

Thx!

[18Fiatsandcounting]

High quality catalytic converters are getting ridiculously expensive, especially in California with all the converter thefts. See:
https://autoricambi.us/1966-1985-fiat-1 ... est-pipes/

You could take it to a muffler shop for suggestions, but one tip about getting the car to pass smog is that the converter has to be totally hot. It usually doesn't work to take it to a smog shop, have it sit for 2 hours before they test it, and then the smog techs only warm it up with 5 minutes of idling before testing, which isn't nearly enough. Ideally, you would do the smog test right after 30 minutes out on the freeway at highway speeds. In practice, depending on which smog shop you use, that may be hard to do.

Most fuel injected Fiats don't have a problem with passing the NOx test. Did Allison do any other modifications other than the exhaust? Anything that might make the engine run too hot (which would increase NOx emissions), like running lean?

-Bryan

[toyfiats]

Just to be clear, you didn't have any issue passing before Allison installed the new exhaust and converter? Was the exhaust all they did, or was there other engine work done at the same time? The FI cars with a new converter are ridiculously clean running, so it doesn't make sense that the converter (if indeed new) would be the source of your current problem.

There's unfortunately plenty of other threads on the dearth of Fiat-friendly mechanics, but that rather than a muffler shop might be your better option to get the root problem.

EDIT: Sorry, just reread Bryan's response and he asked the same thing I did.

[Calman]

Thank you! I agree, the car engine needs to be warmed up before testing and this was not always done at testing.

The high NOX started even before the new Allsion exhaust and CAT converter and got steadily worse after it. The car had a valve job done and new cylinder head gasket but it still had trouble passing SMOG

I did find that one of the valves was out of spec and needed a shim to get it within spec (in Dec2021). I haven't tried to SMOG it since so maybe it'll do better now (I can try SMOG testing it after a tune up and before installing a new CAT.)

When say "FI CAT"- what do you mean - is this a brand or ?

[18Fiatsandcounting]

When say "FI CAT"- what do you mean - is this a brand or ?

FI is just shorthand for Fuel Injection, and CAT is shorthand for catalytic converter. California started requiring catalytic converters on all cars sold in CA starting in 1975, and it was required on the "49 state" cars starting in 1979. FI came out in 1980 on California cars and was across the US in 1981.

If you're in silicon valley, you're close enough to where I live (Livermore) that you could pop by some time and I'd take a look at the engine. I can't do smog tests, but I can look things over and see if there's a potential issue.

-Bryan

[toyfiats]

Unlikely this would be the cause if it was having trouble both before and after the recent exhaust work, but check out Bryan's comments in this thread as well. viewtopic.php?p=298057.

Also, over on mirafiori if you search on "nox" you'll get all sort of threads to wade through if you have a spare afternoon or evening. Interestingly enough this thread points to a new cat (specifically a 3-way cat) as the answer to at leas this owner's problems.

https://mirafiori.com/forum/viewtopic.php?p=143696

I will say my own Spider is extremely clean running after a new cat (as a replacement for the original one from 1981), but again, if you have a new cat already that shouldn't be your problem (but never rule it out).

[Calman]

Thanks all- super helpful tips! The car is currently being tuned up at a mechanic so I'll let you know the outcome

Thanks again!

Jay

[18Fiatsandcounting]

Just curious, could you share who your mechanic is? On behalf of Fiat friends, I've made numerous calls in the Bay Area to find a mechanic to work on the "original" Fiat spiders, and I've completely struck out. As in, Can't Find Anyone. Natta, Zero, Zilch.

-Bryan

[Calman]

I have used two Mechanics locally in the California Bay area:
1) Rich at Continental Motors in Sunnyvale +1 408 733 1360. Rich has serviced my car since I bought it in 2002

2) Chris Obert in Santa Cruz 831-423-0218 who I have used less frequently- he has great attention to detail but has a long waiting list

Feel free to text first and then call me at 408 425 6051 if you'd like to talk about it

Jay