GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Fuel Injection Pump and Lines

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REMOVAL & INSTALLATION



See Figures 1, 2 and 3

The V6 and V8 diesel injection system may use either a CAV injection pump, or a Roosa-Master/Stanadyne pump.

  1. Disconnect the negative battery cable, then remove the air cleaner assembly.
  2.  
  3. Remove the filters and pipes from the valve covers and air crossover.
  4.  
  5. Remove the air crossover, then cap the intake manifold with screen 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, then remove the filter from the vehicle.
  14.  
  15. Disconnect the fuel inlet line from the pump.
  16.  
  17. Remove the rear A/C compressor brace and the fuel line.
  18.  
  19. Disconnect the fuel return line from the injection pump.
  20.  



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Fig. Fig. 1: V8 diesel fuel injection system circuit



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Fig. Fig. 2: Offset on diesel injection pump driven gear

  1. Remove the clamps and pull the fuel return line from each injection nozzle.
  2.  
  3. Using two wrenches to prevent damage to the fittings, disconnect the high pressure line from the nozzles.
  4.  
  5. Remove the three injection pump retaining nuts with tool J-26987 or its equivalent.
  6.  
  7. Remove the pump. then cap all lines and nozzles in order to prevent system contamination.
  8.  

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.  



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Fig. Fig. 3: Timing marks and injection pump lines-V8 diesel engine

  1. Install, but do not tighten the pump retaining nuts.
  2.  
  3. Connect the high pressure lines to the nozzles.
  4.  
  5. Using two wrenches, torque the high pressure line nuts to 25 ft. lbs. (34 Nm).
  6.  
  7. Connect the fuel return lines to the nozzles and pump.
  8.  
  9. Align the timing mark on the injection pump with the line on the timing mark adaptor and torque the mounting nuts to 35 ft. lbs. (47 Nm).
  10.  

A3/4in. 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:
    1. Remove the clip from the Cruise Control rod and 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.  

  2.  
  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. To adjust the transmission cable:
    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 the snap-lock until it is flush.
    6.  
    7. Release the injection pump lever.
    8.  

  12.  
  13. Connect the negative battery cable, then start the engine and check for fuel leaks.
  14.  
  15. Shut the engine OFF , then 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 filter in the valve covers.
  18.  
  19. Install the air cleaner assembly.
  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.  

SLOW IDLE SPEED ADJUSTMENT



See Figures 4 and 5

  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.  



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Fig. Fig. 4: Diesel injection pump slow idle screw-Roosa Master/Stanodyne



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Fig. Fig. 5: Slow idle screw-CAV diesel injection pump

FAST IDLE SOLENOID ADJUSTMENT



See Figure 6

Through 1979
  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.
  6.  
  7. If equipped with A/C disconnect the compressor clutch wire and turn the A/C on. Then 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 in order to activate the solenoid.
  8.  
  9. Adjust the fast idle solenoid plunger to obtain 650 rpm.
  10.  



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Fig. Fig. 6: The fast idle solenoid is mounted on the side of the injection pump

1980 and Later
  1. With the ignition OFF, disconnect the single green wire from the fast idle relay located on the front of the firewall.
  2.  
  3. Set the parking brake and block the drive wheels.
  4.  
  5. Start the engine and adjust the solenoid (energized) to the specifications on the underhood emission control label.
  6.  
  7. Turn the ignition switch OFF and reconnect the green wire.
  8.  

Cruise Control SERVO RELAY ROD ADJUSTMENT

  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.  

 
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