Robot Head

From the Lost America photostream on Flickr:

Smogging

Unfortunately, in 2004 California repealed the law that let old cars roll off the smog testing regimen once they got to be 30 years old or so, ending with the 1975 model year ... just in time for me to acquire a pair of 1976 F10s that are increasingly hard to make pass.  Sigh. Just one more year and I would have lucked out ... as smog test guys are always happy to remind me.

So, what does an F10 have in the way of smog gear? Basically, not a lot, especially on the 49-state leaded gas car. There's an air pump to reduce HC, a PCV valve, a very basic carbon canister setup for evaporative emissions, and an EGR valve to lower NOX to something reasonable. The California car adds a 2-way catalytic converter to reduce HC and CO. As near as I can tell the cat must do next to nothing, as the HC and CO standards are the same and both cars blow the same numbers. Maybe it's gone bad.

When the Sportwagon arrived I trucked on over to the gas station a short distance away that I usually get cars smogged at, where it promptly failed for NOX (alarmingly high numbers across the board), the evaporative system, and of course the gas cap. I should have known the ancient Stant locking cap wouldn't hold for the pressure test; the hatchback had the same problem. A quick trip to Kragen and the old cap went into the trash, replaced with a cheap new non-locking cap.

The NOX and the evap issues were a bigger deal. I might have tackled the NOX myself, as the only system in play was EGR, but I had neither the time nor experience to mess with the fuel system. Also, I wasn't sure what it would take to get the car to pass and didn't want to get in an endless cycle of paying for a test, failing, tweaking, etc.

This kind of thing is why California has the Gold Shield shop program -- designated repair places that can basically keep working on your car until it passes.  Lozano Auto Service in Sunnyvale was recommended by a couple of people, and I dropped the Sportwagon off along with the service manual for what turned out to be a week's stay.

When it arrived, they did an initial smog test, and the numbers were even worse than at the first place:

Clearly, the EGR system was completely non-functional. According to the shop owner, they first checked the valve to make sure it wasn't sticking, something I'd already done. It's easy to just reach down underneath the valve and actuate it with your finger. Next up was vacum to the valve. That's supplied by a simple thermal switch that opens once the engine warms up. They pulled off the hoses and found that the switch was plugged with a small piece 0f red plastic "like off a can of WD-40." Oregon must have had nothing more than a simple visual inspection, if that. I wonder if the past owner's meticulous logbooks make any mention of that!

After removing the plastic, the thermal switch was found to be dead. One replacement later and we had a working EGR system again. And it still failed.

Head-scratching time. They removed the EGR valve and cleaned all passages to eliminate any restrictions. It still failed.

Finally, they did a top engine clean using Seafoam to try to knock the compression down a bit by removing carbon. The car passed! But only by the skin of its teeth.

Why such a big problem with such a simple system? I suspect a few things were at work. First and foremost, with no 3-way cat, a wimpy EGR system, and relatively high compression for 1976, NOX was probably never that low even factory new. Second, the Sportwagon was tuned for leaded gas, which is nominally more like mid-grade 89 octane unleaded than the cheap 87 I had in the tank. Higher octane, lower NOX since the combustion is cooler. Finally, I would be surprised if one can of Seafoam completely decarbonized the head.

Next time I'll make sure the tank is full of premium, or even racing gas if necessary, and hope for the best.