well right now my 12 valve is a stocker.i know if i go big fuel i need more air or i can get myself into some trouble.im lookin for performance but i am really trying to get this truck to blow lots of smoke.i was told by an injection pump guy that the pumps on the 1st gens are set to the max when they were put in the trucks.my truck tag says that the manufacture date of this rig was07-91 so its a later 91.please help.

 

oh yeah i almost forgot to answer one of your questions. it is an intercooled cummins.the truck is super cherry.the only thing i need is a front bumper.i got it from some 20 year old kid whos dad was the origional owner and the kid drove it for six months said it was slow and needed somethin faster so i picked this thing up for only 2500 buks.91 d250 4x4 with the intercooled 12 valve automatic.pretty darn good i think.

 

2500 dollars, damn good deal. The fuel pumps aren't maxed out from the factory. There is an article in the 1st gens section here that has all the details and instructions of turning them up. I'm gettin ready to turn mine up just as soon as I get some gauges. Pyrometer is definitely a necessity.

 

thats a clean 89 bud i sure would like to know how to turn this pump up.now does this pump have a fuel plate or just that bully dog 40 horse fuel pin

 

how do i get to where it tells you how to turn up the pump. im new to this site

 

I don't know about that, I havent dug into mine yet. I've never really worked on diesels, just drove'em. Go to the thread under this one entitled, "turnin up a '93." Should be the same thing as yours, or http://www.genosgarage.com has directions and details on it too. Check those out, should be very helpful. I helped a friend of mine turn his up a couple of weeks ago. Not hard at all, just write down what u do, how many turns, etc. so you can turn it back if need be.

 

Did u figure it out, you can navigate the site easiest at the top of the page. That's how I get back to different sections.

 

yeah i figured it out but am confused on the pump.the screw i turned up is dead center on top of pump with 13mm jamm nut and torx bit in center, i turned it clockwise till the jamm nut would almost not go back on but didnt get any smoke.there is a black piece just in front of that is plummed to manifold is that what i need to pull of with 2 screws.there is a flathead down inside there but i didnt mess with that

 

Don't mess with that, I don't know what it does, if anything. The smoke screw is located on top of the diaphragm cover underneath a thin piece of of metal countersunk into the cover, directly in the center from what I can tell. Underneath of the diaphragm cover is the fuel pin and the AFC star wheel adjustment. Be careful taking that apart, like I said, I havent done mine yet because I haven't got the gauges. Then, if u read the article, the other adjustment screw is on the back of the pump. I read the article several times, print it out if you can and take it outside with you. It will all make sense if you look at side by side. Hope this helps you out.

 

I just played with my smoke screw a little bit? Does anybody know how far u can turn it before you mess something up. I've had some response from it, defintely more low end power. I figured that one was safe to mess with because it really shouldn't affect egt's, but, how far can u go?