GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Diesel Fuel Injection

Print

See 1, 2, 3, 4 and 5

GM diesel engines are equipped with Roosa-Master, CAV-Lucas, or Stanadyne injection pumps. The Roosa-Master and Stanadyne pumps are nearly identical.

IDLE SPEED ADJUSTMENT

A special tachometer with an RPM counter suitable for the 263 V6 and 350 V8 diesels is necessary for this adjustment; a standard tach suitable for gasoline engines will not work.

  1. Place the transmission in Park, block the rear wheels and firmly set the parking brake.
  2.  
  3. If necessary, adjust the throttle linkage as described in Drive Train of this guide.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Fast idle temperature switch-V6 diesel engine

  1. Start the engine and allow it to warm up for 10-15 minutes.
  2.  
  3. Shut off the engine and remove the air cleaner assembly.
  4.  



Click image to see an enlarged view

Fig. Fig. 2: CAV-Lucas Injection pump slow idle screw

  1. Clean off any grime from the timing probe holder on the front cover; also clean off the crankshaft balancer rim.
  2.  
  3. Install the magnetic probed end of the tachometer fully into the timing probe holder. Complete the remaining tachometer connections according to the tach manufacturer's instructions.
  4.  
  5. On V6 diesels equipped with air conditioning, disconnect the A/C compressor clutch lead at the compressor.
  6.  



Click image to see an enlarged view

Fig. Fig. 3: Roosa-Master injection pump slow idle screw

  1. Make sure all electrical accessories are OFF, then disengage the 2 lead connector from the generator.
  2.  

At no time should either the steering wheel or brake pedal be touched.

  1. Start the engine and place the transmission in Drive (after first making sure the parking brake is firmly applied).
  2.  



Click image to see an enlarged view

Fig. Fig. 4: Fast idle temperature switch-V8 diesel engine



Click image to see an enlarged view

Fig. Fig. 5: Fast idle solenoid-V6 diesel engine

  1. Check the slow idle speed reading against the one printed on the underhood emissions sticker. Reset if necessary.
  2.  
  3. Unplug the connector from the fast idle cold advance (engine temperature) switch, and install a jumper wire between the connector terminals.
  4.  

DO NOT allow the jumper to ground.

  1. Check the fast idle speed and reset if necessary according to the specification printed on the underhood emissions sticker.
  2.  
  3. Remove the jumper wire and reconnect the temperature switch.
  4.  
  5. Recheck the slow idle speed and reset if necessary.
  6.  
  7. Shut off the engine.
  8.  
  9. Reconnect the wiring leads at the generator and A/C compressor, as applicable.
  10.  
  11. Disconnect and remove the tachometer.
  12.  
  13. If equipped with Cruise Control, adjust the servo throttle rod to minimum slack, then put the clip in the first free hole closest to the bellcrank or throttle lever.
  14.  
  15. Install the air cleaner assembly.
  16.  

 
label.common.footer.alt.autozoneLogo