Lessons Learned on the Injection Pump Rebuild

Nozzle Masters in Orlando, Florida, rebuilt the pump in two days and charged $424. It took another 2-1/2 hours to reinstall the pump, prime the fuel system, and start the engine. In addition to the DIY dollar savings I appreciate how much I learned about the 4BT's entire fuel system—including how to bleed it.

Lessons Learned 

Removing and reinstalling the fuel injection pump is well within the reach of the do-it-yourselfer. The order of removal is: (1) the seven fuel lines; (2) the wire attached to the cutoff solenoid; (3) the throttle bracket; (4) the pump support bracket; (5) the three bolts holding the pump to the engine; and (6) the nut and lock washer holding the pump to the gear. It's not necessary to completely remove from the engine the seven rigid fuel lines which connect to the fuel pump. They do have to be given a little play though. For the four rear-facing injector lines this is accomplished by removing the lines' two retaining clamps (mounted on top of the engine).

The fuel line from the filter attaches to the pump in two locations. Simply removing this line's tee fitting will free the pump. Finally, the fuel return line is small enough to be pushed clear after it's unscrewed. After each fuel line was unscrewed from the injection pump its end was sealed, from foreign matter intrusion, with blue tape.

 After removing the big plastic cap from the front of the engine, which gives access to the nut and lock washer holding the shaft to the gear, stuff a rag inside the opening to catch any falling nuts or lock washers. Think of this as cheap insurance because if a part does drop inside the engine it'll be a lot of work to get it out. The only special tool needed was a gear puller. I used one but I'll bet tapping on the injector pump's shaft with a brass mallet would be just as effective.

 During removal there's no need to lock the pump's drive shaft, as both the Cummins and Lucas manuals call for.  Just make sure the engine is not rotated while the injection pump is off or the timing can be  messed up.  The Cummins has a top dead center (TDC) locking pin located just inboard of the injection pump.  I rotated the engine to TDC and pushed the pin in before removing the pump.  The pin was left in place until after the pump was reinstalled.  Don't forget to withdraw the pin before starting the engine.

 With the engine at TDC for cylinder #1 the manual lift pump works, i.e. the engine's lift pump lobe is disengaged.

 Bleeding the engine was done by: (1) hand pumping the lift pump; (2) opening the two bolts on the high pressure side, with the engine cranking, until the escaping fuel had no air in it; and, then (3) loosening the fuel line connection at the injector for cylinders 1 & 4. It took about 15 seconds of cranking until the engine started.

 The Nozzle Master tech said he likes to advance the pump's timing a little. For the Cummins this is done by rotating the injection pump clockwise (while facing towards the bow). I did not try this but rather used the existing factory timing marks.