Anyone have a 78/79 and live somewhere where emissions are enforced? My 78 f100 351m passes the idle test but it's doesn't pass the stupid visual inspection. The paper says air injection system not present. The smog pump is on the truck. I know I'm missing a lot of stuff. Can someone post pictures of their emission controls setup.

 

Air pump turns ambient air into Secondary Air which is either dumped on the ground or sent to a valve which routes it to the head(s) or to the exhaust system. It is all controlled by vacuum and engine (coolant) temperature.

If that air pump/Thermactor system is like what Fox Body 5.0s have, then you have the pump, the hose from the pump output to the Bypass Valve, then a hose from the Bypass which leads to the Diverter Valve. There are two hoses out of the Diverter in addition to the one going in. The Diverter Valve routes the air to either the backs of the heads (Upstream) where it gets injected into the exhaust ports, or farther back into the exhaust piping (Downstream).
The Bypass Valve either sends the Secondary Air to the Diverter Valve, or dumps it to the atmosphere. Some Fords used a combination Bypass and Diverter valve.

So if you know about electronics, then think of the entire Thermactor system as a relay. The above-described Secondary Air part of the system is your Secondary Circuit.

The 'Primary circuit' would be the control side of the system, and that circuit uses vacuum.
Typically, the vacuum is sourced at the manifold, and then routed to a Temperature Controlled Vacuum Switch, which threads into the intake manifold, into a water jacket. The TCVS senses the coolant temp, and at a certain temperature, it switches vacuum between its two 'outlets,' the 'inlet' being where it's plumbed to manifold vacuum. There might be two different TCVS's controlling the system.
There might be a 'schematic' for the entire vacuum system and Secondary Air circuits on the V.E.C.I. label, where it gives you the plug gap and idle setting info - or did these trucks not yet have those?

Do you have the metal tube which bolts to the rear of your heads? It should have a big check valve on the end so it won't leak exhaust, or someone might've capped it off if they left the air tube in place.


So it looks like the hose just needs to be connected to the pump.
And that appears to be a Bypass Valve connecting the hoses. Maybe your truck doesn't use a Diverter Valve, and only sends Secondary Air to the exhaust or the atmosphere. Follow that hose back, and see where it goes. If you have a nice new exhaust, chances are it isn't connected, but if it is, and there's not exhaust coming out, then that tells you that that big check valve is still doing its job.

Once you've got that part of the system connected like it's 'sposed to be, then you just need to connect some vacuum hose and apply a vacuum to that Bypass Valve while the engine is idling. You should be able to hear a subtle difference if the valve holds vacuum and switches properly. You might see the dirt on the ground under the truck get blowed around, when it dumps air.
Some Bypass Valves default to dump, with no vacuum, while others are configured to dump when vacuum is applied.
If you still have your original intake manifold, then the TCVS may well still be there, and ready to be plumbed with vacuum.

So your priority would be to find out what exactly the truck came with, as far as the Thermactor system is configured, or at least what Big Brother is wanting to see on there at a minimum...
Can you take a pic of the top and passenger side of the engine with the air filter assembly removed?


Chances are that you're really not missing all that much of the system, and that you need only some vacuum lines, that hose reconnected to the pump, and worst case scenario, a bung welded to the appropriate spot in your exhaust, to connect to the system. I guess they could tell you that you need Secondary Air going to your exhaust ports, and that you could have heads which are not set up for those. That would be bad.
Oh, and another way Secondary Air gets distributed directly to the exhaust port area is when you see brake-line sized metal tubing going to the exhaust manifolds at each cylinder, but I don't think Ford used that method much after the '60s-early '70s.

Someone should be along with some better, more specific, info, but for now, you at least have a description of what you are/could be facing.