Are Emissions Inspections in the US ever a moving target for car owners?

Many jurisdictions in the US require regular emissions inspections for vehicles registered there. I’ve been under the impression that the inspection is supposed to verify that the current emissions match either the maximum permitted under emissions law in the year the car was built (which might be no standard at all/unlimited emissions if the car is a Ford Model T or something that old), or the emissions that the car was designed to meet when it was made (which might be below the maximum permitted for cars in general). That is, emissions failures indicate that something is broken or horribly out of tune on your car that used to work, rather than indicating that it’s time to upgrade or enhance your car.

I understand that there is pressure on manufacturers to produce less-polluting NEW cars, but that is not what I’m talking about here.

Is this true? Are emissions inspections ever a moving target for people who own older cars? E.g.:

J. Random Oldcarowner: “I need a Safety and Emissions inspection done on my 1989 Lincoln Town Car.”
<inspection ensues>
Mechanic: “Your car failed.”
J. Random Oldcarowner: “Can you repair it so it passes?”
Mechanic: “The car isn’t broken - there’s nothing to fix. The thing is is that the state recently lowered permitted carbon monoxide levels to half of what this car was designed for. Even if this thing were brand spanking new, just off the lot with 50 miles on it, it would still fail.”
J. Random Oldcarowner: “What can I do?”
Mechanic: “Not a whole lot, unfortunately. You could contact the local mod scene and see if they know someone who can stick a new Honda Civic engine or something in it, but I don’t know if anyone’s done that and then successfully passed and there are no warranties on such work because of how experimental it is. Good luck. Oh, here’s a card for the local scrap dealer.”

This is purely anecdotal but I will give it a shot.

About a month ago a 1976 Ford Truck came to our shop and the owner wanted his vehicle to pass the California SMOG test. Apparently it belonged to his father who recently died and he had plenty of cash to burn so my boss took the job. My boss is the one who mainly worked on it but he assigned me to replace the headers on the truck so they will accept what he called a “smog pipe”. The point of the smog pipe was to allow an air pump to pump fresh air to the exhaust so any excess fuel that made it past the engine would be lit up before it hit the catalytic converter. You never want raw fuel getting to your catalytic converter, it will damage it. Anyway after all was said and done he ran the vehicle on the dynomometer and it barely passed the SMOG test by the rust of its bumper. So it is possible although costly.

Here in NC these cars/trucks don’t have to pass the emissions inspection:

Vehicles 35 years old, or older
Model 1995 vehicles, or older
Diesel-operated vehicles
Vehicles licensed under the farmer rate

Because they use the OBD system and those cars do not have that system.

My understanding is that vehicles need to pass the emission requirements for the model year of the car. The standards do not change for any given vehicle.

Every car I’ve owned passed the tests with significant margin when new and continued to pass for as long as I’ve owned them, provided they were in repair. I keep cars for 10 to 15 years.

Federal requirements apply only to the manufacturer (I assume requirements in effect at the time of the manufacture are what’s relevant). State emissions are, as far as I know, based on the car model year. Regulators don’t really want conversations like the hypothetical one in the OP to happen (at least not for consumer items like cars).

But of course, older cars are more likely to have something that’s broken or failing, so it’s not surprising that older cars need more repairs to meet emissions tests.

Is that “smog pipe” something that would be necessary even on a new truck of that vintage? Or is it instead a cheap alternative to a much more substantial repair? I.e. the truck in new condition would pass, but to be restored to such a condition you’d have to rebuild or replace the engine ($$$$) or install a “smog pipe” ($$$).

Like others have said, it’s mostly based on the model year of the car; a 1976 Chevy wouldn’t have much at all in the way of emissions controls (a PCV valve is about it) but nor would it be expected to meet very stringent requirements either.

This all depends on the state though, and states like California have long had more stringent requirements than the rest; what a 1976 truck in California might have to pass would probably pass for a 1986 truck in say… Alabama. For a long time there, car makers had the California emissions version, and the other 49 version. Don’t know if they still do.

I’m betting the #2 post left out a couple details. I’m betting it should have read more or less like this:

“Recently somebody brought us a 1976 car. It was originally a non-California-legal car when manufactured. The customer now wanted to register & use the car in California. So he needed it to pass the California smog check applicable to 1976 California-legal cars. We installed some aftermarket parts to upgrade the smog system from 1976 49-state standards to 1976 CA standards. It worked.”

The point being that back in those days California had its own separate more stringent smog standards. And so the manufacturers made 2 kinds of cars, so called 49-state cars, and California cars. Since California was about 25% of the new car market it was worth it to them to go to the extra trouble. As well, Congress liked it because then CA was leading the “green” charge and they could take car industry lobbyist cash to avoid passing the regs, knowing they could upgrade the 49 states later to what CA had already proved was possible.
I know this was true in 1976. I was there then & ran a car shop. I beleive that some time in the mid-late 1980s the Feds caught up to CA and manufactuerer tailpipe emmissions limits are now the same in all 50 states. Although as said above, ongoing inspection requirements vary from state to state & sometimes by location within a state. OTOH, I’m pretty sure there is some Federal regs which withold highways funds from states which don’t do some level of inspections in urban areas. I don’t know the details

I should have mentioned that the truck had a carburetor and vehicles with carburetors typically run rich just to be on the safe side. You would rather be a little too rich than too lean. For that reason, almost all the oxygen that entered the engine through the intake system will be used up and the raw fuel may make contact with the catalytic converter. You need to burn that fuel for 2 reasons. The first is so you do not damage your catalytic converter and second to heat up your exhaust gasses when the engine is cold. A catalytic converter does not work when cold so that added air makes the catalytic converter heat up faster.

The secondary air injection system is literally an air pump that pumps air into the headers of the engine via the “smog pipe”. The smog pipe is just a pipe with 3 fittings that thread into 3 holes in the new header. This was necessary since the vehicle originally did not have a catalytic converter. I do not know if that is how it came from the factory but that is how it drove to our shop.

Modern cars typically do not need air injection systems. Many cars have heated catalytic converters and fuel injection allows more precise air fuel ratios. There are exceptions. My father owned a 2004 Mazda RX-8 which has a Wankel Engine and that needed an air injection system since by necessity it had to run richer air fuel ratios. This was in NY BTW.

Don’t forget, some states, (at least we do here in Washington), have a maximum amount that an owner is required to spend in order to fix the problem. If spending that amount doesn’t bring the vehicle into compliance, the owner gets a variance that allows driving the car even though it doesn’t meet standards. IIRC, here ths amount is $150. We get so many of these at our shop that it would almost seem to negate the purpose of emmissions testing. Essentially this is just an extra tax on non-compliant cars.

Also, the State of Washington just last week sent out a notice to auto repair shops that because the modern cars are so good at emmisions control, they are going to phase out the testing, and it will be completely gone by 2020.

They probably could have waited a year and skipped all that work and expense. Right now, 1975 and older gasoline-powered vehicles are exempt in California.

Former California smog tech here. (and still working in the industry)
Have the goal posts moved? Well the answer is yes and no.
Back in the 1980s in California’s non-attainment areas (the parts of the state with the worst air quality) were subject to a bi-annual smog check.
The smog test consisted of:
A visual inspection (pass/missing/modified/disconnected)
A functional test of the timing, fill pipe restricter, and EGR system
a tail pipe test at idle and 2500 RPM. The tail pipe test had a max CO reading of 1%. Off the top of my head I don’t recall the limit for hydrocarbons, and NOX was not measured, as we were not doing loaded mode testing.

Now there is still a visual, still a functional test, which has added a test of the evap system (often very hard for an older car to pass due to cracked hoses, etc), and the tail pipe test is done on a dyno. This puts a stress on the entire system. Everything has to work, or it will fail.
Back when I was testing in the 80s and early 90s, I almost never got a fail on a Volvo. The factory spec for CO if front of the cat was 0.6% and the limit was 1.0%. I had cars that I knew for a honest fact had hollowed out cats and they would pass the test at 0.6% CO. Now those cars would fail big time.
Also now with loaded mode testing, they test for NOX which can only be done on a dyno. We never looked for it back then because cars don’t produce NOX except under load. Many of the older car failures are from excessive NOX.
BTW I think that California may have cranked down the limits for CO and HC since I was testing, but I would have to consult a colleague that is still testing to be sure.

In Minnesota, cars more than 10 years old were exempt from the emissions testing. Most states have something like this, though the years vary. I think California’s 25 years is the longest.

But Minnesota dropped the testing a few years ago, because it wasn’t accomplishing much. About 99% of the vehicles tested passed on the first test, with no adjustments needed. They were running within the limits. The Legislature dropped the program, since so few polluting cars were found for the expense of the program.