D4-7J4256 All of a sudden after 67 years.

The best way to track down a faulty injector is to swap the suspect around to another cylinder and see if the problem follows. If all are affected that's another story.

Yes, you can clean the orifice of the injector if that is the problem.
Takes a 0.5mm drill (carefully) for the 4-1/4 in. bore engine (D4400)

I got some moisture in the fuel and after six monthes I found out about the moisture and that things grow in the tank. I flushed the tank good and did my dozer work. I took the tank off and dried out and had it steam cleaned. After a couple rinses the tank seems fine but the filters were starting plug also.
Good luck. Clay

What I found dozens of times is if a nozzle goes bad it will drive compression back into the whole fuel system through the bad nozzle and cause all kinds of problems so then the best thing to do is take them all out and have them checked or you can remove the nozzles one at a time and put the fuel line back on them and start the engine and see if you get a spray or just a stream coming out and that would be the bad one.Always keep the nozzles pointed away from you as that is pretty high pressure and can be dangerous.

Changed the filters and had a terrible time bleeding the filter tower-should have filled it b/4 bleeding but I'm old and forgot. Acts like its not getting fuel. Has no power at all then just takes off and runs fine for 10-15 seconds then loses power. Almost like the governor isn't working right? I don't have a parts book but remember posts a while ago talking about a spring that makes the fuel rack move to increase fuel. It has worked fine for 4700 hrs and 67 years.
Any input is appreciated.
Thanks,
BullDozerBob

Still could have some air in the fuel system yet so start at the filter base with the base bleeder and then the top cover bleeder and then go to each inj. pump and bleed them good individually and see if it helps the problem.

Took the cover off below the injection pumps and found #3 stuck in the up position--got it freed and it runs like a dream! There is a little rust on the sliding rods and the round ones --I cleaned them and everything slides well. Where do they get lubrication from? There is a reservoir below this area that I have changed the oil in. Got lucky!
Thanks for the replies.
BullDozerBob

Glad ya found the problem. You'd think things would last more than 67 years, wouldn't ya? 😆

I was getting fuel at the inlet to all the injectors which threw me for a loop--thats why I thought an injector was plugged. SJ nailed it when he said wierd things happen to fuel systems. There are tubes off the top of the injectors--are they some kind of bypass? Anyway after I freed the stuck pump lifter and went to start the diesel it started on two cylinders and I had to bleed more air from all of them and the filter tower b/4 all cylinders fired. I'll see tonight if there is still air in the system when I fire it up. Can I use a litte greese to lube those slides below the injector pumps? I will change the oil in that reservoir below the pumps as well.
Thanks again.
BullDozerBob

I was getting fuel at the inlet to all the injectors which threw me for a loop--thats why I thought an injector was plugged. SJ nailed it when he said wierd things happen to fuel systems. There are tubes off the top of the injectors--are they some kind of bypass? Anyway after I freed the stuck pump lifter and went to start the diesel it started on two cylinders and I had to bleed more air from all of them and the filter tower b/4 all cylinders fired. I'll see tonight if there is still air in the system when I fire it up. Can I use a litte greese to lube those slides below the injector pumps? I will change the oil in that reservoir below the pumps as well.
Thanks again.
BullDozerBob