D4400 fuel system question

Deano,

Try taking the cover off the side of the injector pump. Make sure all of the plungers are moving freely. It sounds to me that two are stuck. Just free them up and give the a shot of oil.-glen

😕 I finally had time today to check the plungers on #2 and #3, I found them to be moving freely so I put the cover back on, took #2 and #3 injectors out and reconnected them to the fuel line and cranked over the engine. Fuel sprayed out in a nice cone pattern on both injectors. I put them back in and started the engine but it still only ran on #1 and #4. I decided to see what would happen if I loosened #1 and #4 line, the engine stayed running on #2 and #3, as soon as I tightened the lines for #1 and #4 they began firing again but #2 and #3 began to miss. I thought that maybe someone had installed 2 of the plungers one tooth off on the rack so I checked all of them and all of the marks line up. Is there something else I should look for?? Thanks for your help. Dean

Swap #1 & #4 injectors with #2 & #3 and see if problem follows the injectors. Even though they showed a good spray they may not be adequate under firing conditions. Would also be a good idea to have the injectors tested if you can locate a facility that can do it.