rack question ffuel press

Try running the engine and see if it runs wide open ok at full throttle and if not then you,ll need to check into it deeper. You didn,t say what serial number you have but the small capsule type nozzles like in the 4U & 5U are 700 psi breaking pressure for a new nozzle and used ones can go down to 550 or 575 psi and still work.I don,t have the specs for the big nozzles (injectors) used in the earlier engines but someone here I,m sure does.

the rack needs the extra space. When you set to full idle and then load the engine the rpm drops the gov acts to move the fuel rack to increase the fule delivery to attempt to maintain the rpm

1931tim - You need to state your tractor S/N so we know what kind of fuel system we are talking.

You really need the fuel injection valve, proper test apparatus, to test break pressure accurately. You do a leak-down test as well as check break pressure and spray pattern.
You can check spray pattern with the injectors removed from the head, reconnected, and pointing out from the engine, on the tractor .. but you need the proper injector tester to do the pressure and leak-down tests.

The break pressure for all 3¾" (D3400) and 4¼" (D4400 & D4600) bore Cat engines, with the early-style, flat-seat fuel injection valves, is 1500 psi.

The break pressure for the later capsule-style injection nozzle (4" bore, D311 engine), is between 300 and 800 psi. If it breaks below 300 psi, the capsule style injection nozzle needs to be discarded,and replaced with a new one. There are no adjustments or repairs than can be made to capsule-style injection nozzles.

In addition .. the leak-down test for capsule style nozzles, states that you hold the pressure at 300 psi, and if the pressure drops more than 100 psi in 30 secs, the nozzle must be discarded.

my serial is 5u4883 I can take them to my local shop but they had no info on them thank you. the rack if I move it clear forward it springs back to center. It moves very easy and smooth, the local shop had it apart and cleaned and resealed it and checked it as far as they could but they had no specs or test setup for it.

It sounds like you are putting the local shop's kids through college.

Theses old machines are pretty tough and forgiving. I have found that usually it is something really simple (and cheap) wrong with my machine when it won't run. I for sure could afford this hobby if I had to run to the local shop for repairs.

I've read a lot of posts on here in the past that make it sound like people have a heck of a time bleeding their fuel system, but I really haven't ever had a hard time with either of my machine's fuel. I've taken all four injector pumps off, adjusted the lifter settings, reinstalled the pumps and just cracked the lines until I had fuel flowing out them all. Tightened them and fired up the machine. Once when I first started messing with these old things I removed the nozzles, swung the injector lines out from the diesel and then tightened them back to the nozzles, the nozzles just spitting fuel out over the tracks, so I could see them working while I spun the diesel with the pony.

Could you have gotten some trash in the hole where the transfer pump mates with the diesel when you were installing the pump? The O-ring get knocked out of place and blocking some of the hole? When you open the upper bleed (the wheel on the upper front of the filter housing), does fuel pump out of the drain line under the transfer pump? You should get good flow out of the bleed line. If no, then either the pump is crap, the pump outlet is blocked or something else is restricting fuel from the pump. If you get good drain, and you can crack the injector lines and get flow, then maybe setup the nozzles outside of the head so you can watch them spit fuel and see what it does. Just turn the machine over a few times and you'll see if the injectors are passing fuel. Might sound nutty, but you will see if fuel is coming out of the injectors and nozzles.

when i got this thing it was in pieces the pump was apart ,the gov., head , pony, thats why i took it over to them. Plus it was a freebee. I put new inj on it and i do have fuel comming out of both bleeds there is fuel pulsing out of inj. lines and press is mid red on pony. I don't know of any where i'm chasing air yet. I have some spare inj. I will spin a line around and watch the spray. I have never had this kind of problem getting any modern stuff running. thats why I am asking to make sure i am not missing anything. far from the new inj.systems running in the 50,000psi injection range

Don't mis-read my post. I wasn't trying to condemn you. I just never take something to a shop. Part of my enjoyment (I must have issues) is fixing these old things on my own. But, then of course you get into the cost of tools required for everything and maybe I would save money going to a shop sometimes.

So, everything must be in time, because you stated someplace that it ran after lots of grease on the pump gears, but then started missing, right? I just don't know. All I can say is divide and conquer. You have to start determining what is good, then move to the unknowns and keep ruling stuff out. You have flow, you have pressure on the gauge. Does the gauge actually read correctly? What can you trust and what do you not trust regarding all the parts of the fuel system? I can't remember everything you have done. Just make sure-
Flow from tank good.
transfer pump pumping.
Transfer pump bypass not failing.
Fuel flowing into filter housing.
Filters are good and clean.
Fuel flowing to the injector pumps.
Injector pump lifter adjustment correct.
Rack opening.
Fuel passing through injectors.

Heck, what else is there? One thing for sure, you'll be the fuel system authority when you get it running.

With the capsule type injecton valves you can't test the spray pattern outside the engine unless you have an extra pre chamber to clamp them in, the fuel will not seal unless it is clamped down in the pre chambler. The instructions showing this are for the early style flat face valves.

Tom