I am wanting to see if the divertor valve in the air injection system is working,it has two vacumn lines going to it and I presume one controlls the air going to the back of the heads and the other to the convertor. I do not have a shop manual but I need to know the operation of the divertor valve and what each vacumn line controlls,I read somewhere that when the motor is cold the air is injected in the back of the heads to tell the computor the motor is too lean so it will give a richer fuel mixture when cold. When cold my truck stumbles a little and acts like its running too lean but when warm it runs fine so I need to know how to see if the divertor valve is operating correctly if thats how its supposed to work. Jeff

 

I can't help you specifically on the air-injection system, but I can point you toward www.fordfuelinjection.com They explain how the computer works during warm-up, but basically it doesn't use much info from the various sensors, but works off of pre-programmed fuel/air parameters until the HEGO sensor is hot enough (~600F) to work properly. At that point, the computer goes into closed-loop mode and uses various inputs to determine proper operation and fuel/air mixtures.

Jason

 

Haynes prints a Techbook #10210 Automotive Emissions Control available at Advanced or Autozone for about $16 that describes in Chapter 4 how the diverter and switching valves, check valve, bypass valve and the air control solenoids work. A book worth having.