Mazda 323/626/929/GLC/MX-6/RX-7 1978-1989

Fuel Injection Pump

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REMOVAL & INSTALLATION



You will need a suitable puller and two M8 x 1.2 x 45mm bolts to remove the injection pump drive pulley.

  1. Disconnect or remove the following items:
    1. Battery negative cable.
    2.  
    3. Throttle cable.
    4.  
    5. Cruise control cable (if the car has cruise control).
    6.  
    7. Cold start device control cable.
    8.  
    9. Fuel cut valve and pickup coil connectors.
    10.  
    11. High pressure injection lines (remove and cap openings).
    12.  
    13. Remaining fuel and vacuum hoses.
    14.  
    15. Rear timing belt cover.
    16.  

  2.  
  3. Rotate the crankshaft to align the matchmarks of the fuel injection pump pulley with the adjacent mark on the rear seal plate. (The similar mark on the rear camshaft pulley should also align with the nearby mark on the rear seal plate.)
  4.  
  5. Mark the rear timing belt for direction of rotation. Loosen the rear tensioner lockbolt, then use a screwdriver to turn the tensioner clockwise and loosen it; hold the tensioner in this position. Tighten the lockbolt to retain the tensioner in the fully released position, then remove the timing belt from the pulleys.
  6.  
  7. Install the two bolts through the holes in the injection pump drive pulley and thread them into the seal plate behind it. Remove the locknut and washer from the center of the pulley. Remove the bolts. Then, use a puller to remove the pulley from the injection pump shaft, being careful not to lose the Woodruff key.
  8.  
  9. Use a drift to precisely mark the relationship between the rear flange of the injection pump and the seal plate. This will avoid the need to re-time the injection pump if you are planning to service and reuse the present unit.
  10.  
  11. Have an assistant support the injection pump. Use a socket and long extension to remove the injection pump attaching bolt and nuts. Remove the pump.
  12.  

To install:
  1. Position the pump on the mounting flange, then install the attaching bolt and nuts just until they touch the rear of the pump flange. Turn the pump carefully to precisely align the matchmarks made earlier. When these marks are precisely aligned, torque the nuts to 14-18 ft. lbs. (19-24 Nm). and the bolt to 24-34 ft. lbs. (33-46 Nm).
  2.  
  3. Install the Woodruff key onto the pump driveshaft, and lightly tap it with a lightweight hammer to make sure it is fully seated in the groove. Then, slide the pulley over it and onto the shaft.
  4.  
  5. Align the matchmarks on the pulley and seal plate, then install the two bolts used to keep the pulley from turning during removal. Install the locknut and torque it to 44-50 ft. lbs. (60-68 Nm).
  6.  


WARNING
Once the locknut is properly tightened, be sure to remove the bolts which were used to lock the pulley in position.

  1. Install and adjust the timing belt as described in Engine & Engine Overhaul . Unless a new belt is being installed, make sure the belt will be turning in the same direction.
  2.  
  3. Install the items which were disconnected or removed in Step 1, in reverse order of disassembly.
  4.  
  5. Operate the pump on top of the fuel filter by repeatedly depressing the large knob until it can no longer be readily moved. This will bleed the system.
  6.  
  7. If you installed a new injection pump, properly set the pump injection timing.
  8.  

INJECTION TIMING



See Figures 1, 2, 3 and 4

To perform this procedure, you must have a special dial indicator and mounting jig designed for this particular job. The Mazda part number is 49-9140-074; you may want to shop around to get the equivalent tool from the least expensive source.

  1. Run the engine until it reaches normal operating temperature. Remove the high pressure injection lines as described earlier, leaving the pump fittings uncapped.
  2.  
  3. Remove the service hole cover from the top of the flywheel housing, then rotate the engine to align the TDC (thicker) mark on the flywheel with the indicator pin inside the hole.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Turn the crankshaft to align the TDC timing mark on the flywheel with the indicator pin



Click image to see an enlarged view

Fig. Fig. 2: Mount the measuring jig into the plug hole on the hydraulic head of the pump

  1. Remove the delivery valve assembly from the top injection pump fitting, as shown in the illustration. The valve is removed by placing a socket wrench on the flats (the injection line cap screws onto the outer valve). Make sure you keep all valve parts together, in order, and in a clean environment. Supply a new gasket and discard the old one. Remove the hydraulic head plug from the front surface of the injection pump.
  2.  
  3. Mount the measuring jig and dial indicator into the plug hole on the hydraulic head of the pump. The tip of the dial gauge should contact the plunger end of the pump, with the gauge indicating approximately 0.08 in. (2.0mm).
  4.  
  5. Turn the flywheel counterclockwise (in reverse of normal rotation) until the crankshaft pulley timing mark moves from TDC to about 30-50° BTDC and the dial indicator stops moving. Then, zero the indicator. Turn the crankshaft slightly to the right and left to make sure its motion does not affect the indicator. If it does, the timing must be advanced further before zeroing the indicator.
  6.  
  7. Now, turn the flywheel clockwise to set the timing mark to TDC. Read the dial indicator. The reading should be 0.0392-0.0408 in. (0.98-1.02mm). If not, loosen the pump nuts/bolt and turn the pump until the figure is correct. Turn the pump clockwise if the figure is too high (timing is advanced), or counterclockwise if it is too low (retarded). Retorque the nuts to 14-18 ft. lbs. (19-24 Nm) and the bolt to 24-34 ft. lbs. (33-46 Nm). Remove the timing device, then install the delivery valve with a new gasket and torque it to 36 ft. lbs. (49 Nm).
  8.  
  9. Connect the injection lines, then bleed the system by repeatedly depressing the large knob on top of the fuel filter until it can no longer be readily moved.
  10.  



Click image to see an enlarged view

Fig. Fig. 3: Turn the flywheel 30-50 degrees counterclockwise before zeroing the dial gauge



Click image to see an enlarged view

Fig. Fig. 4: After setting the timing, install and torque the delivery valve to specifications

BLEEDING THE SYSTEM



See Figure 5

If the engine runs out of fuel during operation and air enters the injection system, or whenever the injection pump is removed, the system must be air-bled in the following manner:

  1. Bleed air from the fuel filter's vent plug.
  2.  
  3. Pump the head of the fuel filter repeatedly until it becomes hard (about 15 times).
  4.  



Click image to see an enlarged view

Fig. Fig. 5: Bleed air by repeatedly depressing the large knob on top of the fuel filter

 
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