ENGINE COMPRESSION
Check engine compression with engine at normal operating temperature, all spark plugs removed (on dual plugs, remove exhaust side only), and throttle wide open. Ensure crankcase is full and oil is of correct viscosity. With compression gauge installed, use remote starter to crank engine.
Crank engine at least 5 revolutions, 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. No cylinder compression reading should be less than 100 psi (7 kg/cm 2 ).
| Application | Compression Ratio |
|---|---|
| 5.0L | 9.0:1 |
| 5.8L | 8.8:1 |
COMPRESSION RATIO SPECIFICATIONS
VALVE CLEARANCE
Note. All models are equipped with hydraulic valve lifters; valve adjustment is not required. If incorrect valve clearance is suspected, collapse lifter before checking clearance.
| Application | In. (mm) | |
|---|---|---|
| 5.0L | ||
| Allowable | .071-.171 (1.80-4.34) | |
| Desired | .091-.151 (2.31-3.84) | |
| 5.8L | ||
| Allowable | .092-.192 (2.34-4.88) | |
| Desired | .112-.172 (2.84-.4.37) | |
COLLAPSED VALVE LIFTER CLEARANCE
HIGH TENSION WIRE RESISTANCE
| Application | Ohms |
|---|---|
| Bronco | 7000 Per Foot |
HIGH TENSION WIRE RESISTANCE
SPARK PLUGS
| Application | Motorcraft No. |
|---|---|
| 5.0L | ASF-42C |
| 5.8L | ASF-32C |
SPARK PLUG TYPE
| Application | (1) Gap In. (mm) | Torque Ft. Lbs. (N.m) |
|---|---|---|
| 5.0L | 0.052-0.056 (1.3-1.4) | 7-15 (9-20) |
| 5.8L | 0.042-0.046 (1.07-1.17) | 7-15 (9-20) |
| (1) If Vehicle Emissions Information decal contradicts spark plug gap specification in table, use information on decal. | ||
| (1) | If Vehicle Emissions Information decal contradicts spark plug gap specification in table, use information on decal. |
SPARK PLUG SPECIFICATIONS
FIRING ORDER & TIMING MARKS
Note. For firing order and timing marks (Scheme 2)- (Scheme 4).
Firing Order & Timing Mark ID (4.9L). Scheme 2
Identifying Firing Order & Timing Marks (5.0L & 7.5L). Scheme 3
Identifying Firing Order & Timing Marks (5.8L). Scheme 4
IGNITION TIMING
| Application | Degrees BTDC |
|---|---|
| Bronco | (1) 10 |
| (1) With SPOUT in-line connector unplugged. | |
| (1) | With SPOUT in-line connector unplugged. |
BASE IGNITION TIMING
FUEL PUMP
Note. Fuel pump performance is a measurement of fuel pressure and volume availability, not regulated fuel pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.
| Application | Specification |
|---|---|
| Pressure | (1) |
| Volume | (2) |
| (1) For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. (2) Volume is 1 Pt. (.5L) in 30 Seconds. | |
| (1) | For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. |
| (2) | Volume is 1 Pt. (.5L) in 30 Seconds. |
FUEL PUMP PERFORMANCE
IDLE SPEED & MIXTURE
Note. Idle mixture is not adjustable. If idle mixture is incorrect, see TESTS W/CODES - EEC-IV article in the ENGINE PERFORMANCE section.
| Application | RPM |
|---|---|
| Bronco | (1) |
| (1) Idle speed is computer controlled and is not adjustable. | |
| (1) | Idle speed is computer controlled and is not adjustable. |
IDLE RPM SPECIFICATION
THROTTLE POSITION (TP) SENSOR
| Application | Idle | Wide Open Throttle |
|---|---|---|
| Bronco | 0.34 | 4.84 |
| (1) Minimum idle and maximum wide open throttle specifications are given. | ||
| (1) | Minimum idle and maximum wide open throttle specifications are given. |
TP SENSOR VOLTAGE SPECIFICATIONS (1)