I have been having problems with my truck passing NYS emissions for for several years now since it was required. Changed the oil, fuel filter, made sure air cleaner and pre-heater were clean, replaced the overflow valve and the lift pump. Even had the injectors out twice and had them tested.
I was ready to have the injector pump replaced when I started reading this forum about AFC and the fuel plate. I was looking at AFC and noticed the break off screw had been already removed and replaced with a bolt. The plate had been ground down and the AFC appeared to be missing some components.
Here are some pics.

 

That would do it. Might be able to find an AFC foot for sale on here, or might have to go to a Bosch shop.

 

too bad your from down state, were exempt from emissions here in wny...

 

What does the AFC foot do? Or what is it suppose to be doing? And why remove it? And as far as finding one on this forum is it as simple as just asking who has one they would sell?

 

Hey Tom...why is it that the same state can have different rules? Maybe its the county that I'm in(Suffolk).

 

controls fueling , if afc arm is removed it lets the gov arm travel to the fuel plate as soon as the throttle is pressed - dumping mass amount of fuel under not boost conditions

 

Yup, your county. more people down there, they have to keep the air cean for you. Up here all our polution goes your way

 

here is a good picture

 

I dont know but im glad im from upstate... That stuff is a real PITA

 

I was trying to copy any paste that same photo to use as an example but couldn't use it. But I do see the "foot" that's missing on mine.
I did figure out how to access to classifieds on the web site to find a replacement.

 

Just found out the vacuum line to the AFC wasn't even connected. I found the
end of the hose connected to the manifold was barely hanging onto to the fitting. Somehow the hose melted at the fitting and sealed itself at the manifold sealing the hose so I had no leak. And there was no vacuum to the AFC at all.

 

The foot is the large silver colour piece in the picture, has the blue paint on it. That advances forward based on the spring rate and boost pressure fed to the housing. That 'vacuum' line is the manifold pressure signal line. Very little vacuum there (thats why our trucks have vacuum pumps), it transmits the pressure from the manifold to the AFC to increase fueling based on boost pressure.

Why remove them? It gives you absolute control over the fueling, save for the governor. That means you can be at full rack travel at idle if you so choose, which will equate to massive amounts of smoke and very little power. Get the AFC back in and you can tune it so its as clean as you like it. I wouldn't bother with the plate, as that won't help you pass emissions if its just a snap test.

 

Tate...so I should leave the plate out. But from looking at the AFC photo I would need the foot in place. Then I can tune it with the star wheel....correct?

 

Correct

 

So I take it you thought that all 12 valves were that fast?