Fuel Pin Stuck?
 

I posted a while back about my lousy gas milage and was blaming the tires and went off on a tangent and then kinda backed off of the tire thing being the problem because there just wasn't enough difference in the tire circumference to make that kind of difference in the mileage. The other thing that I did during that same time frame was to install a 3200 rpm spring. After I installed the spring, I took the thing out and checked to see if it would turn 3200 rpm...know what I mean?... Anyway... I saw more power and boost than before and also saw the 3200 rpm's... After that, my gas milage (on the highway, sustained runs) dropped from 22mpg down to about 17mpg. My question to the guys out there that hotrod these things is... can the fuel pin get stuck in the open position and cause the IP to constantly feed fuel as if it has a high amount of boost? Could I have pushed the pin to an area where ther was no wear or something and it just stuck. What is the easiest way to find out? I want to take it apart but I am afraid if I bother it, it wll just pop back and not give any indication of ever being stuck. Can I just plug off line to the diaphram. Is it possible and what are some indications that this has happened? Thanks... Rockfoot

if the pin is worn or stuck you will be able to see a grove when you take it out. its not going to hurt to pull it out and take a look.also what kind of pin do you have? lastly it would be better to find the problem vs. blocking off the boost line from the diafram caus thats what pushes the pin down and if you do that you will have very minamal fuel.

That's kinda what I was getting at... if I block the boost off to the diaphram and I still got smoke on acceleration, wouldn't that indicate that the pin was stuck?... It is a stock pin and never been out of the IP.

you probably didnt get the arm in place when you replaced the spring.The arm the pin coresponds to can get stuck in the wrong position.Did you remove the fuel screw when you took the top off?if not you may have broke the arm inside

I took the fuel pin out and I think it was stuck. I t really didn't want to come out. It had old grease on it and the wear mark was not bad. Looked good. After I cleaned it, I noticed two wear marks on the pin. I think it has been out before and was put back in, in a different place. I put it back like it came out. While I was under there, I noticed that the little vacuum gauge thingy on the air filter had raised up in side the tube, indicating that the air filter might be clogged. It is a K&N filter, so I took it out and cleaned it with the appropriate cleaner from the kit and re-oiled and reinstalled it. The truck runs good but it will be a while untill I see if the mileage has increased. Not sure about the diesels with the turbos but atmospherically aspirated engines use a lot more fuel when they are starving for air.
Did you remove the fuel screw when you took the top off? Yes.. This is the third one that I have done and have not had any problems until this one.