Heres the story, I replaced the injectors and IP two days ago. I lined the pump up line to line, and It cranked up no problem. Now it doesn't have any power at all. I can accelerate in any gear to 3000 rpms, then it just stays there until i let off the gas and punch it to the floor, then it will go past 3000. It struggles just to make a hill unloaded. What did I do wrong?? does the gear that the IP connects to move? Like jump a notch while i was installing the pump or does a chain or something keep it from moving without bumping the motor? That is all I can think of. PLEASE, any help would be greatly appreciated. It also has a new filter and Lift pump.:help: :help:

Look right behind the top cover of the pump, you should see a 3/16" allen guide stud and 1/2" nut. If there is a gap between the top of the nut and the head of the guide stud, loosen the nut, and turn the stud in a couple flats and retighten the nut.

This is your Hi Idle adjustment, probably got set too low, if not, then the linkage gap got set too long and the pump needs to be recalibrated.

Check throttle linkage. have someone hold the throttle down while you check for W.O.T. Check fuel pressure next.

Ya'll were both right. there was a gap on the high idle screw and the lift pump was not working. I fixed both of them, the truck is better, but it still seems to me that it isn't up to full strength. TDG, you said that the pump may have to be recalibrated; does it have to come off the truck for that?? or is that the little screw behind the cover on the side of the pump? speaking of that, I tried to turn the IP up like QM said awhile back: 1/2 turn clockwise. the only problem was, it wouldn't turn that much, so I put it back as close as I could to original. should it have forced it a little more or what? It would only go about an 1/8 of a turn, 1/4 at the most. I don't know, could that be the problem?? Please keep the sugg. coming.

Hey I thought I had the right answer, no fair! Sometimes the leaf spring screw will bottom out when turning up the fuel, so turn it 1/4 or 1/2 should do it for fuel. What model pump did you install? Could be the wrong one.

Wrong? Really? I thought that there weren't that many choices for mechanical, but most all would work?

The mechanical turbo pump has larger plungers. It probably needs to be a DB2-4911, but there are a few others that will work. There's quite a few different mechanical pumps out there, some better than others depending on year and application. Some shops have tried to make a stanadard DB2 pump work by screwing the leaf way in, but that won't work, and maybe that might be the case here as well.

The IP that came off was a 4911 and the one I put back on was the same number. So I can just turn the screw until it stops? Because I can't get a 1/2 turn. And could that be the source of my power loss even though the old pump was never turned up??

Perhaps you could have a shop turn up the tranfer pressure and leaf for you, they would be able to say if the pump was giving the right output.

Also, I think the truck runs better if you loosen the three 15mm nuts holding it to the timing cover and push the pump to the driversside a few mm's.

1/2 turn is quite a abit on a 4911 pump, assuming they calibrated it to 68~69cc's, 1/2 turn will be more than enough.

As far as static timing, you should advance the pump to compensate for timing chain wear, definitely with a higher mileage engine, line to line timing will be retarded.