Tune-Up - v6 Ford Ranger

ENGINE IDENTIFICATION

Engine can be identified by the 8th character of the Vehicle Identification Number (VIN). VIN is located on a plate attached to upper left corner of instrument panel, near windshield.

Note. When ordering engine replacement parts, refer to the label located on engine timing belt cover.

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 Emission Control Label in engine compartment before attempting tune-up. If manual and label differ, always use label specifications.

Do not allow or create a condition of engine misfire in one or more cylinders for an extended time. Damage to converter may occur due to loading converter with unburned air/fuel mixture.

ENGINE COMPRESSION

Test compression with spark plugs removed, engine at normal operating temperature and throttle wide open. Crank engine through at least 5 compression strokes before recording reading.

COMPRESSION SPECIFICATIONS

SPARK PLUGS

SPARK PLUG TYPE

SPARK PLUG SPECIFICATIONS

HIGH TENSION WIRE RESISTANCE

Remove spark plug wires from plugs. Remove distributor cap with wires attached. Check resistance of each wire by connecting one ohmmeter lead to cap terminal and the other lead to spark plug end of wire. If resistance is over 7000 ohms per foot, 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.

HIGH TENSION WIRE RESISTANCE (OHMS)

2.8L

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

2.9L & 3.0L

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

VALVE CLEARANCE

2.8L 2-Bbl. engines are equipped with mechanical lifters. To adjust, set engine to TDC of No. 1 cylinder. Check valve clearance and adjust. Repeat operation for all cylinders in order of engine rotation.

2.9L and 3.0L MPFI engines are equipped with hydraulic valve lifters. Adjust all valves to zero lash.

VALVE CLEARANCE ADJUSTMENT - 2.8L

1. Engine must be cold for correct valve clearance adjustment. Remove valve covers. Turn engine until intake valve of No. 5 cylinder just starts to move into open position. Adjust both valves for No. 1 cylinder. (Scheme 5)
2. Intake valve clearance is correct when.014" (.36 mm) feeler gauge is snug or drags lightly while.015" (.38 mm) gauge is very tight. Exhaust valve clearance is correct when.016" (.41 mm) feeler gauge is snug or drags lightly while.017" (.43 mm) gauge is very tight, refer to VALVE CLEARANCE ADJUSTMENT TABLE. (Scheme 5)
3. To adjust valves in cylinder firing order (1-4-2-5-3-6), rotate engine so that intake valve is just opening on cylinders in order 5-3-6-1-4-2. Adjusting screws are self-locking type. Turn screw clockwise to reduce clearance or counterclockwise to increase clearance. (Scheme 5)
4. Use (1) feeler of each size to adjust clearances rather than stepped "go/no-go" gauge. When checking clearances, feeler gauge must enter gap from leading or trailing side of rocker arm pad. Gauge must be moved to opposite side of pad in motion parallel to centerline of crankshaft. CAUTION: DO NOT use a step-type "go/no-go" feeler gauge. Measuring valve clearance in direction perpendicular to crankshaft will result in poor feel. Valves measured in this incorrect manner will be adjusted too tightly. Damage to valves or valve seats will result.
5. Install valve covers (be sure to use new valve cover gaskets and reinstall cover reinforcement plates). Start engine and check for oil and vacuum leaks.

Valve Clearance Specifications (2.8L). Scheme 5

VALVE CLEARANCE ADJUSTMENT

DISTRIBUTOR

All engines are equipped with the TFI-IV EEC-IV ignition system. No adjustments are required on any of these systems.

2.8L, 2.9L & 3.0L Timing Marks & Firing Order. Scheme 6

IGNITION TIMING

Note. Timing instrument should be connected to No. 1 one spark plug wire using an adapter or clip-on connector. Do not puncture spark plug wire or boot to make connection.

1. Turn off all lights and accessories. Set parking brake and place transmission in Neutral. Ensure A/C and heater are off. Connect timing light and disconnect the single wire in-line spout connector or remove the shorting bar from the double wire spout connector.
2. Start engine and warm to normal operating temperature. Check timing and adjust if necessary. Reconnect spout connector or reinstall shorting bar. Check timing advance to verify distributor is advancing properly. Remove tachometer and shut off engine.

IGNITION TIMING (DEGREES BTDC @ RPM)

IGNITION TIMING (1)

HOT (SLOW) IDLE RPM

Note. All engines are equipped with automatic idle speed control (ISC) and idle adjustment is not a normal tune-up procedure. If idle speed is not correct, perform the following procedures as part of a full EEC-IV diagnosis.

Scheme 7

1. Turn off all lights and accessories. Place transmission in Neutral or Park. Start and warm engine to normal operating temperature. Set parking brake and block wheels.
2. Remove Air Charge Temperature (ACT) sensor and adapter from air cleaner tray, keeping wiring harness connected. Remove air cleaner. Disconnect and plug vacuum line at cold weather duct and valve motor.
3. Turn ignition off. Within 10 seconds, Idle Speed Control (ISC) plunger should move to maximum extension. Disconnect ISC and disconnect and plug EGR vacuum hose. Restart engine and manually open throttle. Set fast idle adjusting screw on highest step of fast idle cam. (Scheme 7) (Scheme 7): 2.8L 2-Bbl. Idle Speed Control Adjustment Motorcraft Model 2150A Feedback Carburetor (This Is Not A Normal Tune-Up Procedure)
4. Adjust fast idle RPM to specification. Open throttle manually to release fast idle cam and allow throttle lever to reset on ISC plunger. Loosen ISC bracket lock screw. Adjust ISC bracket screw to 2000 RPM. Retighten bracket lock screw.
5. Reconnect ISC. RPM will automatically be adjusted to curb idle. At the same time, manually hold throttle above 1000 RPM, push ISC plunger until it fully retracts and release throttle and quickly unplug connection. Adjust anti-dieseling speed throttle stop screw to specification.
6. Reconnect ISC and EGR vacuum hose. Shut engine off. Restart engine and verify curb idle speed.

HOT (SLOW) IDLE RPM SPECIFICATIONS

2.9L MPFI

1. Turn off all lights and accessories. Place transmission in Neutral. Ensure A/C and heater selector is turned off. Bring engine to normal operating temperature and shut off. Disconnect the idle speed control air by-pass power lead.
2. Start engine and operate at 2000 RPM for 2 minutes. Allow engine speed to drop to idle and ensure base idle is within specification. If base idle speed is not to specification, adjust speed at throttle plate stop screw. (Scheme 8)
3. Turn engine off. Restart and ensure base idle speed is correct. Readjust if necessary. Turn engine off and reconnect power lead to ISC air by-pass valve. Ensure throttle plate is not sticking in throttle bore.

2.9L MPFI Base Idle Speed Adjustment (This Is Not A Normal Tune-Up Procedure). Scheme 8

HOT (SLOW) IDLE RPM SPECIFICATIONS

Scheme 9

1. Turn off all lights and accessories. Place transmission in Neutral or Park. Ensure A/C-Heat selector is off. Apply parking brake and block wheels.
2. Bring engine to normal operating temperature and check for vacuum leaks downstream of throttle plates. Disconnect spout line (single line connector), or remove shorting bar (double line connector), and ensure ignition timing is correct. Readjust if necessary.
3. Shut off engine and disconnect air by-pass valve assembly connector. (Scheme 9) Remove PCV entry line at PCV valve. Install Orifice Tool (T86P-9600-A) in PCV entry line. Orifice diameter is 2" (5.0 mm). (Scheme 9): 3.0L MPFI Throttle Plate Stop Screw Adjustment (This Is Not A Normal Tune-Up Procedure) NOTE: If electric cooling fan comes on during idle set, unplug fan motor or wait until fan shuts off before starting procedure.
4. Start engine and let idle in Drive or Neutral. If idle speed is not within specification, adjust throttle plate screw. After idle has been set, shut off engine.
5. Restart engine and check idle speed after 3 to 5 minutes. If not within specification, repeat step 4). After idle speed is within specification, shut off engine, remove orifice tool and reconnect PCV entry line. Reconnect spout line (single line connector), or replace shorting bar (double line connector).
6. Reconnect ISC motor and cooling fan. Verify throttle plate is not stuck in bore and that throttle plate stop screw is setting on rest pad with throttle closed. Restart engine. After 3 to 5 minutes verify that engine RPM is within specification.

HOT (SLOW) IDLE RPM SPECIFICATIONS

IDLE MIXTURE

Note. This procedure is for 2.8L 2-Bbl. engines only. Idle mixture on 2.9L and 3.0L MPFI engines is controlled by EEC-IV computer and no adjustments are is possible. Idle mixture adjustment is not part of a normal tune-up. DO NOT adjust mixture unless carburetor has been disassembled or vehicle fails emissions testing.

MIXTURE SCREW CAP REMOVAL

Note. Before any idle mixture adjustment can be made, idle mixture limiter caps must be removed. If adjustment is required, use the following procedure to remove caps

1. Remove carburetor from vehicle and drain fuel. Turn carburetor over and locate locking tab on each limiter cap. Use a blunt punch and light hammer to tap tab in until locking detent is cleared in locking cup. Remove cap. (Scheme 10) CAUTION: Support area under limiter cap when removing to prevent bending adjustment needle.
2. Repeat step 1) for other limiter cap. Install carburetor. After propane adjustments have been made, install new caps on both adjusting screws. To install caps, position locking tab in line with detent in locking plug and press cap into plug.

Removing Idle Mixture Limiter Caps. Scheme 10

Propane Enrichment Procedure Vehicle Preparation

1. Apply parking brake and block wheels. Check ignition timing. Readjust if necessary. Remove air cleaner assembly. Disconnect wiring harness from carburetor feedback solenoid at rear of carburetor.
2. Remove PCV valve from valve cover and allow it to draw fresh air. Disconnect fuel evaporating purge line at purge solenoid. Install adapter into end of purge line, (from intake manifold spacer). Install Purge Line Tester (T84T-9600-A) into end of purge line still connected to intake manifold spacer.
3. Disconnect ISC motor from wiring harness by connecting tachometer to engine, starting engine and manually holding throttle above 1000 RPM. Push ISC plunger until it fully retracts. After plunger retracts, release throttle and quickly unplug connection.
4. Be sure throttle lever is resting on speed screw and engine is at Anti-Dieseling RPM specification. Install air cleaner assembly, but do not connect flexible fresh air tube to air cleaner duct and valve assembly.
5. Insert propane hose about 3/4 of the way into duct and valve assembly. If necessary, secure hose with tape.

Propane Enrichment Procedure

1. Leave all vacuum signal hoses attached to air cleaner assembly when relocating air cleaner for carburetor adjustments. Air cleaner must be installed and the air charge temperature switch must be connected for engine speed checks. CAUTION: Do not let engine idle for extended periods, as catalyst overheating may cause excessive underbody temperatures.
2. Disconnect crankcase vent hose (filler cap to air cleaner), from air cleaner. Allow hose to vent to underhood air. With transmission in Neutral, run engine at 2500 RPM for 15 seconds before each mixture check.
3. With engine idling at normal operating temperature, gradually open propane tool valve and watch for engine speed gain. When speed gain reaches maximum and begins to drop off, note maximum amount of speed gain. NOTE: Propane cartridge must be in vertical position. If engine speed will not drop off, check bottle gas supply. If necessary, repeat test with new bottle.
4. Compare measured speed gain with specifications. If mixture adjustment is required, limiter caps must first be removed. Refer to MIXTURE SCREW CAP REMOVAL procedure. If adjustment is not required, go to step 7). NOTE: With limiter caps removed, turn both mixture screws clockwise until seated. Turn screws counterclockwise 2 3/4 turns. If mixture adjustment is necessary, adjust according to RESET GAIN RPM specifications.
5. If measured speed gain is greater than specification, turn mixture screws counterclockwise (rich) in equal increments, rechecking until measured speed rise is within RESET GAIN RPM specifications. Then go to step 7).
6. If measured speed gain is less than specification, turn mixture screws clockwise (lean) in equal increments, rechecking until measured speed is within RESET GAIN RPM specifications. CAUTION: When turning mixture screws verify that screws are no less than 2 1/4 turns from fully seated position.
7. Reinstall mixture caps. Reconnect all components, hoses and PCV valve. Reconnect ISC motor. Remove adaptor orifice from fuel purge line and reconnect purge line to purge solenoid. Remove all test equipment. Reinstall air cleaner. Check and adjust curb idle RPM if necessary.

PROPANE MIXTURE ADJUSTMENT (GAIN RPM)

COLD (FAST) IDLE RPM

Note. No fast idle adjustments are possible on 2.9L or 3.0L MPFI engines

Note. Before performing Cold (Fast) Idle RPM adjustment on the 2.8L 2-Bbl. engine, perform the Hot (Slow) Idle RPM adjustments.

2.8L 2-Bbl.

1. Turn off all lights and accessories. Place transmission in Neutral or Park. Disconnect and plug EGR vacuum hose. Start engine.
2. Place fast idle screw on highest step of fast idle cam. Turn fast idle screw and adjust to specification. (Scheme 11) Return engine to idle. Unplug and reconnect EGR vacuum hose. Turn engine off.

FAST IDLE SPEED (RPM)

2.8L 2-Bbl Fast Idle Speed Adjustment. Scheme 11

AUTOMATIC CHOKE

Loosen choke thermostat cover screws and turn cover in direction indicated on cover to specified setting. Tighten screws.

Note. 1986 model 2.8L engines with Motorcraft model 2150A-Feedback carburetors are equipped with tamper resistant automatic choke systems and no on-car adjustments are required. Linkage may be checked and cleaned with a suitable solution to ensure that choke plate and linkage move freely.

AUTOMATIC CHOKE SPECIFICATIONS

Volume Test

1. Remove air cleaner. Slowly disconnect fuel line at filter. Using a suitable container (one pint minimum), place at end of disconnected fuel line. With high tension wire disconnected from coil, crank engine 10 seconds. If fuel flow is within specification, proceed to pressure test. If not, proceed to step 2).
2. If fuel flow is low, repeat test using remote vented can of gasoline. Remove fuel pump inlet hose. Connect a length of fuel line hose to fuel pump inlet and insert other end into remote can of gasoline. If fuel flow is within specification, problem is plugged intake fuel filter or a kinked, leaking or plugged fuel line or hose.
3. On 2.8L 2-Bbl. models, check that push rod length is 6.10"-6.14". (155-156 mm). If short, replace push rod and install fuel pump. If fuel flow is still low, replace fuel pump. On all models, reinstall coil wire and air cleaner.

Pressure Test

Remove air cleaner. Connect suitable pressure tester to end of fuel line. Start engine and let run for at least thirty seconds. Read pressure and if not within specification, replace fuel pump. Reinstall air cleaner.

ELECTRIC FUEL PUMP

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

FUEL PUMP SPECIFICATIONS

All engines are equipped with the TFI-IV EEC-IV ignition system. No adjustments are required on any of these systems.

TOTAL SPARK ADVANCE @ 2500 RPM (°BTDC)

IGNITION COIL RESISTANCE - OHMS @ 75°F (24°C)

EMISSION CONTROL

For information on emission control systems, see EMISSION section.

FUEL SYSTEMS

CARBURETOR & FUEL INJECTION

BATTERY SPECIFICATIONS

BATTERY SPECIFICATIONS

STARTER

Motorcraft positive engagement type.

STARTER SPECIFICATIONS

ALTERNATOR

ALTERNATOR (WITH EXTERNAL VOLTAGE REGULATOR) SPECIFICATIONS

ALTERNATOR (WITH INTERNAL VOLTAGE REGULATOR) SPECIFICATIONS

ALTERNATOR REGULATOR

Two models of Motorcraft electronic voltage regulators are used. No adjustment is required or possible. They are similar in appearance, but different internally and must not be interchanged.

REGULATOR IDENTIFICATION

SERVICE INTERVALS

Note. On some vehicles, the Service Interval Light will come on after 5000-7000 miles. To reset, depress both Trip and Trip Reset buttons. Light will go out and 3 beeps will be heard.

REPLACEMENT INTERVALS

BELT ADJUSTMENT

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

CAPACITIES

FLUID CAPACITIES