Dynamic Timing
Correct timing specifications vary with cetane value of fuel. Before performing timing test, determine cetane value as follows:
- Obtain a small fuel sample from injection system. Temperature of fuel must be 75-95°F (24-35°C) to obtain accurate results.
- Fill hydrometer container included with Dynamic Timing Meter (078-00200) with fuel until hydrometer floats. Spin container gently to break surface tension of fuel.
- Read number at lowest point of fuel level in hydrometer. Compare reading to DIESEL FUEL CETANE VALUES chart to determine cetane value.DIESEL FUEL CETANE VALUES
Hydrometer Reading Cetane Value .837 50 .846 47 .849 46 .858 43 .862 42 .876 38 - Start and warm engine to normal operating temperature. Coolant temperature MUST be 192-212°F (89-100°C) to obtain correct dynamic timing. Stop engine and connect dynamic timing meter clamps to battery.
- Rotate offset angle control knob clockwise until it stops. Reading on degree scale should be MINUS (-)170 degrees or greater. Rotate offset control knob counterclockwise until it stops. Reading on degree scale should be zero degrees or a positive number.
- If readings are incorrect, have dynamic timing meter calibrated at an authorized service center. If readings are correct, stop engine and install magnetic pick-up probe of dynamic timing meter into timing pointer probe hole. See Fig 1.
- Set dynamic timing meter to MINUS (-)20 degrees. Remove No. 1 cylinder glow plug. Make sure that sight glass in luminosity probe is clean. Install luminosity probe in place of glow plug and tighten to 12 ft. lbs. (16 N.m). See Fig 1. Connect photocell over luminosity probe and connect to timing meter.
- Disconnect cold start advance solenoid connector from terminal. Raise and support rear wheels. Place transmission in Neutral and start engine. Using Throttle Controller (014-00302), set engine speed at 1400 RPM with no accessory load. Read injection timing on meter.
- If injection timing is not within 2 degrees of value indicated in DYNAMIC INJECTION TIMING SPECIFICATIONS chart, timing must be adjusted. If timing is incorrect, stop engine and loosen pump retaining nuts (keeping nuts snug).
- Using injection pump rotator, rotate pump clockwise to retard timing or counterclockwise to advance timing (as viewed from front of engine). Tap rotator with rubber mallet as needed to rotate pump.
- Moving timing mark .030" (.75 mm) is equal to 2 degrees of timing. Retighten nuts. Recheck timing using meter. Repeat step 10) as needed to obtain correct timing. Remove timing meter and other test equipment. Reinstall glow plug using anti-seize compound on threads.
DYNAMIC INJECTION TIMING SPECIFICATIONS
| Fuel Cetane Value | (1) Degrees ATDC | ||
|---|---|---|---|
| 38-42 | 3.5 | ||
| 43-46 | 2.5 | ||
| 47 or Greater | 1.5 | ||
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NOTE:
Also refer to Ford TSB 88-6-23 dated March 16, 1988 for additional information.