I took off the black air intake to look inside where the butterfly is on the intake of the motor. When I opened the butterfly, I was a bit shocked. I seen oil inside of the intake. There was a little right behind the butterfly and some straight back behind the butterfly. There is a hole there that has a tube attached to it. It leads to the PCV valve. Could this be defective.

 

Hey Chuck

Dont get to excited yet. I believe its a mfg. coating on the TB, to catch dust or ?

I read somewhere about coatings on TB and not to clean it off.
Maybe someone here can answer better.

Good luck OT

 

The coating in the throttle body is called DAG, and it is there to be able to hold a very low airflow at idle without having to have the throttle plate closed so far in the bore diameter, (less likely to stick in the bore that way). DO NOT remove it or your idle airflow will be above design specification.

 

"georgekillian"

Was going to buy 3" paddle sander to mod intake size of TB. Part of this mod requires washing out the TB afterwards. What is DAG? If I need to replace it, what should I use and where specifically, would you recommend applying it, ie before/after butterfly, at pivoy points, etc ...

 

Will you be modifying the TB into the area with the coating? The coating is only important where the throttle plate and bore of the casting interface with each other.

DAG is a moly coating that is applied and then heated to cure. I don't believe you can re-apply it and get the same resultant idle settings. I would believe you could modify the manifold side of the Throttle Body as long as you did not disturb the coating AT THE DIAMETRICAL AREA THE THROTTLE PLATE AND THE CASTING MEET EACH OTHER.

 

I don't think everyone understands what I ment. There is actually motor oil in the throttle body. I seen the little sticker saying not to clean with cleaner. I have motor oil getting into the intake which I belive is coming from the PCV valve which leads to the back side of the throttle body. Could it be that my PCV valve is allowing to much oil to go through the system. That might explain my pinging problem. How often do you replace the PCV valve? I can feel a good amount of vacum being sucked into the valve.

 

It's normal. What it is is oil vapors from the valve cover without the PCV (vacuum). All modern vehicles need the intake system cleaned out due to this. this requires removal of the intake. 60,000 miles is usually the number used, but can be extended with normal engine oil change intervals. On my 93, it only had a 3 inch tube so I put a filter inline. It's also why running injector cleaner in the gas is so important every 5,000 miles.

 

georgekillian,

https://www.f150online.com/f150board...ML/002707.html

Has the TB mod. It's the forth post down from Neal. I haven't taken off the TB, so I'm not sure if a simple wash to clear out the sanding dust will effect the DAG material. Based on what you've said, I'll play it safe and tape off the butterfly area if it look like it'll be an issue.

 

I believe I would skip cleaning it with a "solvent" and simply use a clean/new shop towel and compressed air to remove debris from the sanding. Good luck ! !