Repair Pontiac Mid-size 1974-1983 Repair Guide

Injection Pump

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Offset on diesel fuel pump driven gear

  1. Remove the air cleaner.
  2.  
  3. Remove the filters and pipes from the valve covers and air crossover.
  4.  
  5. Remove the air crossover and cap and intake manifold with screened covers (tool J-26996-1).
  6.  
  7. Disconnect the throttle rod and return spring.
  8.  
  9. Remove the bellcrank.
  10.  
  11. Remove the throttle and transmission cables from the intake manifold brackets.
  12.  
  13. Disconnect the fuel lines from the filter and remove the filter.
  14.  
  15. Disconnect the fuel inlet line at the pump.
  16.  
  17. Remove the rear A/C compressor brace and remove the fuel line.
  18.  
  19. Disconnect the fuel return line from the injection pump.
  20.  
  21. Remove the clamps and pull the fuel return lines from each injection nozzle.
  22.  
  23. Using two wrenches, disconnect the high pressure lines at the nozzles.
  24.  
  25. Remove the three injection pump retaining nuts with tool J-26987 or its equivalent.
  26.  
  27. Remove the pump and cap all lines and nozzles.
  28.  

To install:

  1. Remove the protective caps.
  2.  
  3. Line up the offset tang on the pump driveshaft with the pump driven gear and install the pump.
  4.  
  5. Install, but do not tighten the pump retaining nuts.
  6.  
  7. Connect the high pressure lines at the nozzles.
  8.  
  9. Using two wrenches, tighten the high pressure line nuts to 25 ft. lbs.
  10.  
  11. Connect the fuel return lines to the nozzles and pump.
  12.  
  13. Align the timing mark on the injection pump with the line on the timing mark adaptor and tighten the mounting nuts to 35 ft. lbs.
  14.  

A 3 / 4 in. open end wrench on the boss at the front of the injection pump will aid in rotating the pump to align the marks.

  1. Adjust the throttle rod:
  2.  
    1. remove the clip from the cruise control rod and remove the rod from the bellcrank.
    2.  
    3. loosen the locknut on the throttle rod a few turns, then shorten the rod several turns.
    4.  
    5. rotate the bellcrank to the full throttle stop, then lengthen the throttle rod until the injection pump lever contacts the injection pump full throttle stop, then release the bellcrank.
    6.  
    7. tighten the throttle rod locknut.
    8.  

  3. Install the fuel inlet line between the transfer pump and the filter.
  4.  
  5. Install the rear A/C compressor brace.
  6.  
  7. Install the bellcrank and clip.
  8.  
  9. Connect the throttle rod and return spring.
  10.  
  11. Adjust the transmission cable:
  12.  
    1. push the snap-lock to the disengaged position.
    2.  
    3. rotate the injection pump lever to the full throttle stop and hold it there.
    4.  
    5. push in the snap-lock until it is flush.
    6.  
    7. release the injection pump lever.
    8.  

  13. Start the engine and check for fuel leaks.
  14.  
  15. Remove the screened covers and install the air crossover.
  16.  
  17. Install the tubes in the air flow control valve in the air crossover and install the ventilation filters in the valve covers.
  18.  
  19. Install the air cleaner.
  20.  
  21. Start the engine and allow it to run for two minutes. Stop the engine, let it stand for two minutes, then restart. This permits the air to bleed off within the pump.
  22.  

ADJUSTMENTS



Slow Idle Speed


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Fig. Fig. 2 Diesel injection pump slow idle adjustment screw location

  1. Run the engine to normal operating temperature.
  2.  
  3. Insert the probe of a magnetic pickup tachometer into the timing indicator hole.
  4.  
  5. Set the parking brake and block the drive wheels.
  6.  
  7. Place the transmission in Drive and turn the A/C Off.
  8.  
  9. Turn the slow idle screw on the injection pump to obtain the idle specification on the emission control label.
  10.  

Fast Idle Solenoid
  1. Set the parking brake and block the drive wheels.
  2.  
  3. Run the engine to normal operating temperature.
  4.  
  5. Place the transmission in Drive, disconnect the compressor clutch wire and turn the A/C On. On cars without A/C, disconnect the solenoid wire, and connect jumper wires to the solenoid terminals. Ground one of the wires and connect the other to a 12 volt power source to activate the solenoid.
  6.  
  7. Adjust the fast idle solenoid plunger to obtain 650 rpm.
  8.  

Cruise Control Servo Relay Rod
  1. Turn the engine off.
  2.  
  3. Adjust the rod to minimum slack, then put the clip in the first free hole closest to the bellcrank, but within the servo bail.
  4.  

Injection Timing


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Fig. Fig. 3 Diesel timing marks and injection pump lines

For the engine to be properly timed, the lines on the top of the injection pump adapter and the flange of the injection pump must be aligned.

  1. The engine must be off for resetting the timing.
  2.  
  3. Loosen the three pump retaining nuts with tool J-26987, an injection pump intake manifold wrench, or its equivalent.
  4.  
  5. Align the timing marks and tighten the pump retaining nuts to 35 ft. lbs.
  6.  

The use of a 3 / 4 in. open end wrench on the boss at the front of the pump will aid in rotating the pump to align the marks.

  1. Adjust the throttle rod. (See Step 22 of the Injection Pump removal and installation procedure.)
  2.  

 
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