670 Diesel miss

[Joe Pro]

My 670 super diesel has never ran quite right. It runs decent at higher rpm's but has varrying speed at lower rps's. I have replaced the filters many times and put a pickup tube in the fuel tank. I have bleed the system many times also. When I first start it, it surges a bit. It seems that number one and two cylinders are colder to the touch than the back two.

When bleeding the injectors, when I crack number 4 at an idle the engine will die and it will not when the fromt three are cracked. I'm not sure if it is an energy cell issue, injector issue or pump issue? I'm not new to this just don't want to over think it. It seems to surge a bit more than miss but also runs rough at slower speeds, I can watch the tac bounce under 1000 rpm's.
 

[Dieseltech]

You may have injection pump trouble, weight retainer ring may be breaking up inside causing erratic governor control. Just fixed an M-602 pump that had the same problem with surging. If not repaired and retainer pins break off it will take out the head assembly and break the drive shaft, a LOT more costly to fix.
 

[Heath72]

Had the same problem with a 4020 once. It fluttered alot between 1000 and 1200 RPM's, but ran fine at higher speed. They went through the pump, and the problem was the retainer ring went bad. It ran like a new one $600 later!
 

[mikey h.]

you may very well have retainer ring problems in the pump with erratic governor action at idle speed, but do not over look the injector tips they open relativly low around 1850 p.s.i. with a solid core and atomization coning out from the tip for proper pre cup operation.