ENGINE COMPRESSION
Warm engine to normal operating temperature. Check compression at cranking speed with throttle wide open and all spark plugs removed. On engines equipped with dual plug cylinders, remove exhaust side only. Ensure crankcase is at correct level and oil is correct viscosity. With compression gauge installed, use remote starter to crank engine.
Crank engine 5 revolutions (minimum) and record highest reading. Repeat procedure for all cylinders using approximately same number of revolutions. Lowest compression reading should not be less than 75 percent of highest compression reading. Cylinder compression readings should not be less than 100 psi (7 kg/cm 2 ).
| Application | Compression Ratio |
|---|---|
| 4.6L | 9.0:1 |
| 5.0L Except MA (1) | 8.9:1 |
| 5.0L MA (1) | 9.0:1 |
| (1) MA engine is a High Output engine with Mass Airflow Meter. | |
| (1) | MA engine is a High Output engine with Mass Airflow Meter. |
COMPRESSION RATIO SPECIFICATIONS
VALVE CLEARANCE
Note. Hydraulic valve lifters are used and valve adjustment is not required. If incorrect valve clearance is suspected, lifter must be collapsed before clearance can be checked.
| Application | In. (mm) | |
|---|---|---|
| 4.6L | .017-.033 (.45-.85) | |
| 5.0L | ||
| Allowable | .098-.198 (2.49-5.03) | |
| Preferred | .123-.146 (3.12-3.71) | |
COLLAPSED VALVE LIFTER CLEARANCE
IGNITION COIL
| Application | Primary (Ohms) | Secondary (Ohms) |
|---|---|---|
| DIS | (1) | (1) |
| EDIS | (1) | (1) |
| TFI-IV | .8-1.6 | 8000-11,500 |
| (1) Resistance values are not available. For testing, see IGNITION SYSTEMS in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. | ||
| (1) | Resistance values are not available. For testing, see IGNITION SYSTEMS in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. |
IGNITION COIL RESISTANCE
HIGH TENSION WIRE RESISTANCE
| Application (1) | Ohms |
|---|---|
| All Models | 7000 Per Foot |
| (1) DIS & EDIS systems are 30,000 ohms total per wire. | |
| (1) | DIS & EDIS systems are 30,000 ohms total per wire. |
HIGH TENSION WIRE RESISTANCE
SPARK PLUGS
| Application | Motorcraft No. |
|---|---|
| 4.6L | AGSF-32C |
| 5.0L | ASF-42C |
SPARK PLUG TYPES
IGNITION TIMING
| Application | Degrees BTDC @ RPM |
|---|---|
| 4.6L & 5.0L (1) | 10 @ 575-725 |
| (1) On 4.6L, ignition timing is not adjustable. | |
| (1) | On 4.6L, ignition timing is not adjustable. |
BASE IGNITION TIMING
FUEL PUMP
Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.
Note. Fuel pump performance is a measurement of fuel pressure and volume availability, not regulated fuel pressure.
| Application | Specification |
|---|---|
| Pressure | (1) |
| Volume | 1.5 pts. (0.7L) In 30 Seconds |
| (1) For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. | |
| (1) | For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. |
FUEL PUMP PERFORMANCE
IDLE SPEED & MIXTURE
Note. Idle mixture is not adjustable. If idle mixture is incorrect, see appropriate G - TESTS W/ CODES article in the ENGINE PERFORMANCE Section.
| Model | RPM |
|---|---|
| 4.6L | 640 |
| 5.0L | 625-725 |
IDLE SPEED SPECIFICATIONS
THROTTLE POSITION SENSOR/SWITCH
| Throttle Angle | (1) Volts |
|---|---|
| 0° | .50 |
| 10° | .97 |
| 20° | 1.44 |
| 30° | 1.90 |
| 40° | 2.37 |
| 50° | 2.84 |
| 60° | 3.31 |
| 70° | 3.78 |
| 80° | 4.24 |
| (1) Values may vary by 15 percent. | |
| (1) | Values may vary by 15 percent. |
TPS VOLTAGE SPECIFICATIONS