I have the 1988 EVTM, which describes the thermactor system in the same way for the 4.9, 5.0, 5.8 and 7.5 engines. The air pump should feed the bypass valve, which either vents it or sends it to the diverter valve, which sends it to the heads/exhaust manifold or cat. But on my 7.5, I have two lines coming out of my air pump. One feeds the cat all the time, no valve. The other goes to a bypass valve which either dumps the air or sends it to a different place in the cat. There is no diverter valve nor a solenoid for one. My exhaust manifolds... and I know they have been removed by some previous owner... only have a fitting for the EGR, which is in place. This setup actually matches up to what I have on my vacuum diagram on my air box. Has anyone else noticed this?

 

So what is the problem:


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No problem at all, just the EVTM has it wrong so I appreciate that diagram. I was thinking someone may have swapped in some heads from an earlier year or something and took the thermactor system with it. Thanks.