Tune-Up - v8 Ford Thunderbird IX

VEHICLE IDENTIFICATION NUMBER CODE

Engine can be identified by the eighth character of the Vehicle Identification Number (VIN). This number is stamped on a plate located on top left corner of instrument panel.

VIN ENGINE CODES

TUNE-UP NOTES

Note. When performing tune-up procedures described in this article, the following notes and precautions must be followed

Due to late changes and corrections, always refer to Engine Tune-Up Decal in engine compartment, before attempting tune-up. In the event manual specifications and decal specifications are different, always use the specifications on the Engine Tune-Up Decal.

If the Dura Spark 2-piece distributor cap must be removed, first remove top portion, then rotor, and then bottom portion. If any spark plug wire is disconnected with this system, the connection must first be coated with silicone grease before reconnection.

When connecting a tachometer to Dura Spark ignition coil, install the alligator clip on tachometer into "DEC" (TACH TESTING) cavity of coil.

Do not allow or create a condition of engine misfire in more than one cylinder for more than 30 seconds. Damage to converter may result due to loading converter with unburned air/fuel mixture.

ENGINE COMPRESSION

Test compression with all spark plugs removed and engine at normal operating temperature. Crank engine through at least 5 compression strokes before recording reading. Maximum variation between cylinders should not exceed 25 percent.

SPARK PLUGS

SPARK PLUG TYPE

SPARK PLUG INSTALLATION

HIGH TENSION WIRE RESISTANCE

1. Loosen wires from spark plugs by twisting spark plug boot carefully to loosen seal on plug. Remove wires by pulling on plug boot. Remove distributor cap from distributor, leaving wires connected to cap. NOTE: DO NOT disconnect wires from distributor cap unless replacement is necessary.
2. Using an ohmmeter, check resistance of each wire by connecting one ohmmeter lead to spark plug terminal and other lead to distributor cap insert. If any wire has more than 5000 ohms resistance per inch, remove wire from cap and recheck. If resistance still exceeds 5000 ohms per inch, replace wire.

Note. Whenever a high tension wire is disconnected, the interior of spark plug terminal boot must be coated with silicone grease before reconnection.

IGNITION TIMING

Note. Timing instrument should be connected to number one spark plug using adapter or snap-on connector. Do not puncture spark plug wire or boot to make connection. On 5.0L CFI engines with TFI-IV, ignition timing is controlled by the EEC-IV computer and is not adjustable.

Carbureted Models

1. Place transmission in "P" (auto. trans.) or Neutral (man. trans.). Turn air conditioner and heater off. Disconnect and plug vacuum lines at distributor. Connect timing light and tachometer to engine.
2. On 5.8L, disconnect 2-wire connector from ignition module and install a jumper wire between the 2 pins (Yellow and Black wires).
3. On all models, start engine and warm to normal operating temperature. With engine at timing RPM, adjust initial ignition timing. Remove jumper wire. Reconnect all connectors and vacuum hoses. Remove all test equipment.

IGNITION TIMING SPECIFICATIONS

Check fuel pump volume and pressure with pump on engine, engine at idle RPM, and engine warmed to normal operating temperature.

Fuel Injected Models

Disconnect return line at throttle body and connect hose to container. Connect pressure gauge at diagnostic fitting on throttle body. Disconnect wiring connector at fuel tank and apply 12 volts to pump with jumper wire.

FUEL PUMP SPECIFICATIONS

VALVE CLEARANCE

VALVE CLEARANCE ADJUSTMENT

VALVE ARRANGEMENT

1. Right Bank - I-E-I-E-I-E-I-E (Front-to-rear).
2. Left Bank - E-I-E-I-E-I-E-I (Front-to-rear).

DISTRIBUTOR

Models not equipped with MCU or EEC-IV use Dura Spark II ignition systems. MCU models use ECU. EEC-IV models use TFI-IV. No adjustment is required on any system.

5.0L CFI Firing Order & Timing Marks. Scheme 15

5.0L H.O. & 5.8L Firing Order & Timing Marks. Scheme 16

HOT (SLOW) IDLE RPM (CARBURETED)

Note. Relocate air cleaner while making adjustments, but leave all hoses connected. Install air cleaner while making speed checks. Do not apply foot brake on hydro-boost systems as engine RPM will be affected during speed checks.

5.0L 4-Bbl.

1. Place transmission in Neutral. Start engine and warm to normal operating temperature. Place A/C heater selector in "OFF" position.
2. Disconnect and plug vacuum hose at throttle kicker. Adjust curb idle using curb idle speed adjusting screw on throttle lever. (Scheme 17)
3. Increase engine speed momentarily. Let engine return to idle and recheck curb idle speed. Remove plug and connect vacuum hose to throttle kicker.

5.0L 4-Bbl. Curb Idle Adjusting Screw Location. Scheme 17

5.8L 2-Bbl.

1. Start engine and warm to normal operating temperature. Place transmission in "D". Place A/C heater selector in "OFF" position. Disconnect and plug vacuum hose at throttle kicker. Adjust curb idle using curb idle speed adjusting screw on throttle lever. (Scheme 18)
2. Place transmission in Neutral. Increase engine speed momentarily. Let engine return to idle and recheck curb idle speed. Apply a slight pressure on top of nylon nut located on accelerator pump to take up linkage clearance.
3. Turn nylon nut on accelerator pump rod clockwise until a.005-.015" (.13-.38 mm) clearance is obtained between top of accelerator pump and pump lever. Turn accelerator pump rod 1 turn counterclockwise to set lever lash preload.
4. Connect a vacuum pump to VOTM and apply a minimum of 10 in. Hg to VOTM. Check/adjust VOTM idle speed. If adjustment is required, turn saddle bracket adjustment screw. Remove plug and connect vacuum hose to throttle kicker.

5.8L 2-Bbl. Curb Idle Adjusting Screw Location. Scheme 18

HOT (SLOW) IDLE RPM (FUEL INJECTED)

1. Place transmission in "P" (auto. trans.) or Neutral (man. trans.) and set parking brake firmly. Start engine and warm to normal operating temperature. Place A/C heater selector in "OFF" position.
2. On Capri and Mustang, run engine at 2000 RPM for more than 10 seconds in Neutral. Allow engine to return to idle and stabilize for 10 seconds. Place transmission in "R". Adjust curb idle using saddle bracket adjusting screw. If RPM is too low, turn screw clockwise. If too high, turn screw counterclockwise. Repeat steps 1) and 2) until correct RPM is obtained.
3. On all other models, turn engine off. Restart engine and run at 2000 RPM for 60 seconds. Allow engine to return to idle and stabilize for 15 seconds. Place transmission in "R". Adjust curb idle using saddle bracket adjusting screw. (Scheme 19)
4. If RPM is too low, turn engine off and turn screw 1 full turn clockwise. If too high, turn screw counterclockwise. Repeat steps 1) and 3) until correct RPM is obtained.

5.0L CFI Curb Idle Adjustment (Adjust Curb Idle Using Saddle Bracket Adjusting Screw). Scheme 19

CURB IDLE SPEED (RPM)

IDLE MIXTURE ADJUSTMENT

Note. No idle mixture adjustment is possible on vehicles with CFI or MCU. If engine performance is unsatisfactory, EEC or MCU service is required.

Idle Mixture Plug Removal

Remove carburetor from vehicle. Drain fuel bowl. Drill a 3/32" hole in mixture screw plug. Use a screw extractor to remove plug. Install carburetor and make adjustments. After adjustment, install new mixture plug.

Propane Enrichment Procedure

1. Apply parking brake and block wheels. Disconnect automatic brake release, if equipped, and plug vacuum connection. Connect tachometer and timing light to engine.
2. Ensure hot idle compensator is closed (if equipped). Disconnect fresh air duct from air cleaner, and insert propane hose 3/4 way into air cleaner duct. NOTE: Leave all vacuum lines attached to air cleaner. Air cleaner may be positioned aside for adjustments, but must be in place during speed checks.
3. Revise air injection dump valves as follows: If valve has 2 vacuum fittings, disconnect and plug hoses. If only 1 vacuum fitting, disconnect and plug hose, then run a vacuum hose from fitting to manifold vacuum.
4. Check and adjust curb idle and engine timing. Remove PCV valve from grommet and allow to draw fresh air. Run engine briefly at 2500 RPM. NOTE: Propane bottle must be in a vertical position.
5. With engine idling and transmission in "D" (auto. trans.) or Neutral (man. trans.), slowly open propane valve and watch for RPM gain. When RPM begins to drop off, note maximum speed gain. If gain is within "RPM Gain", do not adjust.
6. If not within "RPM Gain", remove carburetor and mixture screw plug. Install carburetor and run engine until warm, then accelerate briefly to 2500 RPM. Proceed with adjustment.
7. If measured speed gain was too high, turn mixture screw counterclockwise (rich) slightly, then repeat propane procedure until gain matches "Reset RPM". NOTE: After turning mixture screw, allow 15 seconds for idle to stabilize before turning screw again.
8. If measured speed gain was too low, turn mixture screw clockwise (lean) slightly, then repeat propane procedure until gain matches "Reset RPM".
9. Reconnect PCV valve and other disconnected hoses. Readjust idle speed if necessary. Remove test equipment.

PROPANE ADJUSTMENT SPECIFICATIONS

Scheme 20

Scheme 21

1. Place transmission in Neutral. Start engine and warm to normal operating temperature. Disconnect and plug vacuum hose at EGR valve. Place fast idle screw on second step of fast idle cam and adjust fast idle RPM. (Scheme 20)and (Scheme 21). (Scheme 20): 5.0L 4-Bbl. Fast Idle Adjusting Screw Location (Scheme 21): 5.8L 2-Bbl. Fast Idle Adjusting Screw Location
2. Increase engine speed momentarily. After engine has returned to idle, again place fast idle screw on specified step of fast idle cam. Recheck fast idle RPM. Reconnect vacuum line to EGR valve and remove test equipment.

1. Place transmission in "P" (auto. trans.) or Neutral (man. trans.). Start engine and warm to normal operating temperature. Disconnect and plug vacuum hose at EGR valve. Disconnect and plug vacuum hose at fast idle pulldown motor. Stop engine on all vehicles, except Capri and Mustang.
2. Set fast idle lever on highest step of fast idle cam. Start engine and check idle speed within 20-60 seconds after engine is started. Adjust if necessary. If time is exceeded, stop engine and repeat procedure. Connect vacuum line at EGR valve and fast idle pulldown motor. Remove test equipment.

5.0L CFI Fast Idle Adjusting Screw Location. Scheme 22

FAST IDLE SPEED

AUTOMATIC CHOKE

No choke adjustment is possible due to riveted, tamper proof choke assembly.

Depending on engine calibration, vehicles are equipped with Dura-Spark II, MCU or TFI ignition system.

IGNITION COIL RESISTANCE (OHMS)

PICKUP COIL RESISTANCE (OHMS)

FUEL SYSTEM

CARBURETORS

FUEL INJECTION

ELECTRICAL SYSTEM

BATTERY SPECIFICATIONS

STARTER

Motorcraft positive engagement type.

STARTER SPECIFICATIONS

ALTERNATOR

Motorcraft external regulator alternator.

ALTERNATOR SPECIFICATIONS

ALTERNATOR REGULATOR

Motorcraft Solid State Electronic Regulator, calibrated and preset by manufacturer. No adjustment is required or possible on this unit.

SERVICE INTERVALS

REPLACEMENT INTERVALS

BELT ADJUSTMENT

BELT ADJUSTMENT TENSION IN LBS. (KG) USING STRAND TENSION GAUGE

COOLING SYSTEM CAPACITIES

COOLING SYSTEM CAPACITIES

ENGINE OIL & FUEL CAPACITIES

ENGINE OIL & FUEL CAPACITIES

TRANSMISSION & DIFFERENTIAL CAPACITIES

TRANSMISSION & DIFFERENTIAL CAPACITIES