I recently had to take the car in for a smog check. In California, any car from 1976 onward has to go through a smog inspection every other year. There was a time when there oldest-year would roll, but I don't recall what the number of years was. It was a rolling 25 or 30 years. But at some point the state government froze it at 1975/1976. So even though my car is now 35 years old, it still has to pass smog.
Now two years ago I had done this right after finishing the cylinder head gasket job. I took it to a British car specialist, figuring they could shepherd it through (I've done this in the past and it worked great). But it wouldn't pass smog; the catalytic converter was shot. That's the big one that sits right below the exhaust manifold. Getting a new cat was a nightmare, because (not sure if this is Calif or Federal) you can't get a junkyard cat even if it's good, you have to buy a new one. But the California twist is that you have to have a specially-certified welder put it in.
That and a laundry list of other things that were fixed, addressed, tweaked and what-all, and $3,000 later, I passed smog.
It's been 2 years, I've only put a few hundred miles on the car. I haven't fussed with the engine. This thing should sail through smog, right?
There's a saying that the man who tries to save money spends the most, and the lazy man works hardest. I didn't want to drive the car 45 minutes away to the Specialist. So I took it to a local guy 10 minutes away, the guy who smogs my (recent) Buick and it always passes.
I knew it was going pear-shaped when I saw he had never seen a Jaguar before (where I live now, I assume that almost all of his cars are recent-year family cars, SUVs and pick-up trucks). He pulled out books and consulted the computer, and I showed him how to do things like pop the hood and roll the windows down.
I failed smog.
So off to the Specialist afterall. They remembered the car from 2 years ago, and we all thought it would be smooth sailing. They looked at the failed smog report and said the guy didn't know what he was doing because he dinged me for not having a part that the car wasn't designed to have.
Fine. Call me when it passes smog and I'll pick it up.
The first call came to tell me that I'd again failed smog, this time for high 02. Various remedies were tried, but no go.
The next couple calls were more of the same. There was talk about replacing the MAF sensor, which made sense to me since mine is I don't know how many years old (I believe it was replaced once already—I know I have a spare in the garage). But they decided to call a Jaguar specialist. My friends and I were referring to him as Yoda, a master Jaguar mechanic who wandered the deep forest and dispensed advice to those who sought him out. "MAF sensor you will buy," is what I figured. (MAF sensors are several hundred bucks.)
Yoda instead suggested The Capictor Fix on the ECM. I've inked this to the article on Jag-lovers.org, but the jist of it is that if the car is cold, they often run rich; the correction is to splice a 25-mike electrolytic capacitor between terminals 6 and 8 of the Air Flow Meter, with the negative terminal on 6.
Didn't work.
What ultimately happened was this; the smog guy was looking around under the car and pointed out that my car a second catalytic converter, located down the tailpipe behind the muffler. So for the second time in two years, I got to buy another cat converter and have it spliced in.
This, plus the usual assortment of other things that got touched, and two months in the shop (literally) and $2,300 later, I got my smog certificate and (eventually) my license sticker.
I looked through my books and saw no mention of a 2nd cat; and the mechanic was surprised as well. The only thing we can think of is that it was added because it was a California car at a time when everyone was stuggling to meet smog requirements.
On the up-side, the smog statistics are way low now. I can run a hose from the exhaust into the house and use the car as a gas-fired air purifier.*
So far, I haven't been able to see an example of this on the internet (not on a 1984). This website has a photo of it, but it's from a 1987. (The photo is down near the bottom of the stack). I wonder what it's like to have an undercarriage that's that clean. I can't imagine that car logs any running or road time.
* - yes, that's a joke.