GM Full-Size Trucks 1980-1987 Repair Guide

Injection Pump Fuel Lines

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See Figures 1 and 2

REMOVAL & INSTALLATION



350 Engine

All lines may be removed without removing injection pump.

  1. Disconnect the batteries.
  2.  
  3. Remove the air cleaner.
  4.  
  5. Remove filters and pipes from the valve covers and air crossover.
  6.  
  7. Remove the air crossover and cap the intake manifold to prevent dirt from entering the intake.
  8.  
  9. Remove the injection pump line clamps. Cap all open lines, nozzles, and pump fittings.
  10.  

To install:
  1. Install the injection pump line. If several lines are being replaced it is best to start with the bottom lines. Torque the pump end of the line to 35 ft. lbs. (47 Nm) and the nozzle end to 25 ft. lbs. (34 Nm). Use a back up wrench on the nozzle upper hex to prevent damage.
  2.  
  3. Install the injection pump line clamps.
  4.  
  5. Remove the caps installed on the intake and then install the air crossover.
  6.  
  7. Reconnect filters and pipes from the valve covers and air crossover.
  8.  
  9. Reconnect the batteries.
  10.  
  11. Start the engine and check for fuel leaks.
  12.  
  13. Shut off engine and then install the air cleaner.
  14.  

379 Engine

When the fuel lines are to be removed, clean all the fuel line fittings thoroughly before loosening. Immediately cap the lines, nozzles and pump fittings to prevent system contamination.

  1. Disconnect both batteries.
  2.  
  3. Disconnect the air cleaner bracket at the valve cover.
  4.  
  5. Remove the crankcase ventilator bracket and move it aside.
  6.  
  7. Disconnect the secondary filter lines.
  8.  
  9. Remove the secondary filter adapter.
  10.  
  11. Loosen the vacuum pump hold-down clamp and rotate the pump in order to gain access to the intake manifold bolt. Remove the intake manifold bolts. The injection line clips are retained by the same bolts.
  12.  
  13. Remove the intake manifold. Install a protective cover (GM part #J-29664-1 or equivalent) so no foreign material falls into the engine.
  14.  
  15. Remove the injection line clips at the loom brackets.
  16.  
  17. Remove the injection lines at the nozzles and cover the nozzles with protective caps.
  18.  
  19. Remove the injection lines at the pump and tag the lines for later installation.
  20.  
  21. Remove the fuel line from the injection pump.
  22.  
  23. Install all components in the reverse order of removal. Follow the illustrations for injection line connection.
  24.  



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Fig. Fig. 1: Fuel line connections, 379 diesel



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Fig. Fig. 2: Torque specifications and fuel line routing, 379 diesel

 
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