1994 PCED OBDI-A
SECTION 20A: Diesel Diagnosis—7.3L IDI Engine
Setting Injection Timing—Dynamic Timing
 

Note: When checking or setting dynamic injection timing on the 7.3L naturally-aspirated diesel or IDI turbo diesel engine it is mandatory that the engine be stabilized at normal operating temperature of 89°C-100°C (192°F-212°F). This temperature is needed to ensure proper fuel ignition in the precombustion chambers.

  1. Bring engine up to normal operating temperature.

Note: To prevent incorrect readings, make sure that vibration damper is clean and free of foreign debris and rust scale. If required, sand the area to remove rust and apply a light coat of paint to the area.

  1. Stop engine and install Dynamic Timing Meter, Rotunda 078-00200 or equivalent, by placing magnetic pickup in timing pointer probe hole (Figure 14 or 15). Insert pickup until it almost touches vibration damper.
  1. Attach clamp from Timing Meter Adapter Rotunda 078-00201 or equivalent to the line pressure sensor on No. 1 injector nozzle (F-Series) or No. 4 injector nozzle (E-Series) and connect to timing meter (Figure 16).




Figure 14: Magnetic Pickup—Dynamic Timing, 7.3L IDI Turbo Diesel Engine




Figure 15: Magnetic Pickup—Dynamic Timing, 7.3L Naturally-Aspirated Diesel Engine




Figure 16: Luminosity Probe—Dynamic Timing

Note: Make sure that all wire leads are located away from the front accessory drive belts.

  1. Connect dynamic timing meter to battery and dial in minus 20 degrees offset on meter. Disconnect cold start advance solenoid connector from solenoid terminal (Figure 11).

Note: Activating cold start advance solenoid can result in engine speed increase. Adjust throttle control to attain 2000 rpm, if required.

  1. With transmission in NEUTRAL and rear wheels raised off the ground, start engine. Using Throttle Control Tool D83T-9000-E or equivalent, set engine speed to 2000 rpm with no accessory load. Observe injection timing on dynamic timing meter. Injection timing should be 8.5 degrees BTDC at 2000 rpm.
  1. Apply battery voltage to cold start advance solenoid terminal to activate it.
  1. Check timing at 2000 rpm. The timing should be advanced at least 1 degree before the timing obtained in Step 5. If the advance is less than 1 degree, replace fuel injection pump top cover assembly.
  1. If dynamic timing is not within ±2 degrees of specification, adjustment of pump timing is necessary.
  1. Turn engine off. Note timing mark alignment. Remove fast idle bracket and solenoid from injection pump. Break torque (keeping nuts snug) on nuts attaching injection pump to pump mounting adapter with Injection Pump Mounting Wrench T83T-9000-B (Figure 2).
  1. Install Injection Pump Rotating Tool, T83T-9000-C (Figure 4), on front of pump. Rotate clockwise (when viewed from front of engine) to retard, and counterclockwise to advance timing, by lightly tapping tool with a rubber mallet. Two degrees of dynamic timing is approximately 0.75mm (0.030 inch) of timing mark movement.
  1. Remove rotating tool and tighten nuts to specification. Start engine and recheck timing.
  1. Repeat Steps 9, 10 and 11 as necessary, to set timing to ± 1 degree of specification.
  1. Turn engine off. Remove dynamic timing components. Install fast idle bracket and solenoid and tighten bolts to specification.