Tune-Up - 4-cyl Dodge Caravan I

IDENTIFICATION

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

VEHICLE IDENTIFICATION NUMBER CODE

Note. Information and specifications for the 2.5L were not available at the time of publication.

The 2.2L engine can be identified by a number located on the rear face of engine block, directly below cylinder head. The 2.6L engine can be identified by a number located on the left side of engine block between rear face of the block and the core plug.

Engine identification may also be determined by the 8th digit of the Vehicle Identification Number (VIN). The VIN is located on a Gray plate attached to left corner of instrument panel.

Note. When ordering engine replacement parts, refer to engine serial number. On the 2.2L engines, the serial number is located on rear face of engine block below the cylinder head and on the right front side of the engine block, next to exhaust manifold stud on 2.6L engines.

ENGINE CODES

TUNE-UP NOTES

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

DO NOT create a condition of engine misfire in more than one cylinder for an extended period of time. The total test time must not exceed 10 minutes or damage to the catalytic converter may occur due to loading with unburned air/fuel mixture.

Also on vehicles equipped with catalytic converters, do not add fuel system cleaning agents to fuel tank or carburetor as cleaning agents may damage the catalytic converter.

If it becomes necessary to replace the Spark Control Computer (SCC), do not disassemble computer for any reason. It is not serviceable and must be replaced as an assembly.

ENGINE COMPRESSION

Using a remote starting switch, disconnect coil wire from distributor and secure to a proper ground. Check the compression pressure at cranking speed with engine warm, spark plugs removed and throttle valve wide open. See COMPRESSION SPECIFICATIONS table.

COMPRESSION SPECIFICATIONS

SPARK PLUGS

SPARK PLUG TYPE

SPARK PLUG SPECIFICATIONS

HIGH TENSION WIRE RESISTANCE

Note. Resistance type spark plug wires are identified by the words "Electronic Suppression" printed on cable jacket. Use an ohmmeter to check for open circuits, loose terminals and/or high resistance.

Spark Plug Wires (2.2L)

1. Carefully remove each spark plug wire from spark plugs. Remove coil wire from coil. Use care not to damage wires during removal. Remove distributor cap without removing coil and spark plug wires.
2. Connect one ohmmeter lead to the spark plug end of wire. Connect remaining ohmmeter lead to the electrode inside distributor cap. Note resistance reading. Repeat procedure for remaining spark plug wires and coil wire.
3. If resistance reading is not within specification, remove spark plug wire from distributor cap. See HIGH TENSION WIRE RESISTANCE table. Positive locking terminal must be compressed from the inside of distributor cap before spark plug wire can be removed. CAUTION: DO NOT attempt spark plug wire removal unless positive locking terminal is compressed from the inside of distributor cap. Spark plug wire will be damaged unless proper removal procedure is used.
4. Check spark plug wire resistance with ohmmeter connected to each end of spark plug wire. See HIGH TENSION WIRE RESISTANCE table for proper resistance specification.
5. If resistance reading is not within specification, replace spark plug wire or coil wire. Check ignition coil tower for carbon tracking, cracks or signs of oil leakage.

HIGH TENSION WIRE RESISTANCE

Spark Plug Wires (2.6L)

1. Carefully remove each spark plug wire from the spark plug and distributor cap. Use care not to damage spark plug wire during removal.
2. Check spark plug wires for damaged or corroded terminals. Connect ohmmeter leads to each end of the spark plug wire. Note resistance reading. Repeat procedure for remaining spark plug wires.
3. If resistance reading is not within specification, replace spark plug wire. See HIGH TENSION WIRE RESISTANCE table.

2.2L

E-I-E-I-E-I-E-I (Front-to-rear).

2.6L

1. Right Bank - All exhaust.
2. Left Bank - All intake and jet valves.

The 2.2L engine is equipped with hydraulic lifters requiring no valve adjustment. Valve clearance is at zero lash with the engine at operating temperature.

Scheme 1

Scheme 2

1. On 2.6L engines, perform valve adjustments after overhaul or service procedures. Cylinder head bolts must be tighten with engine hot prior to valve adjustment. On engines equipped with jet valves, jet valve clearance must be adjusted prior to adjusting intake valve clearance.
2. Start and warm engine to operating temperature. Remove cylinder head cover. Tighten cylinder head bolts to 75 ft. lbs. (103 N.m), in the proper sequence. (Scheme 1)
3. Position No. 4 piston at TDC on the compression stroke. Using a feeler gauge, check exhaust valve clearance. If adjustment is needed, loosen lock nut and turn adjusting screw until proper clearance is reached. See VALVE CLEARANCE SPECIFICATIONS table.
4. Tighten lock nut while holding adjusting screw. Loosen intake valve lock nut, back off adjusting screw 2 or more turns. Loosen lock nut on jet valve adjusting screw.
5. Back off jet valve adjusting screw and place a.010" (.25 mm) feeler gauge between top of jet valve stem and screw. Rotate adjusting screw clockwise until it just contacts feeler gauge. (Scheme 2) NOTE: Since jet valve spring is weak in tensile strength, use special care not to force jet valve inward. Be particularly careful if adjusting screw is hard to turn.
6. While holding adjusting screw, tighten lock nut. Recheck clearance. Adjust intake valve. Complete procedure by rotating engine to position piston at TDC for each remaining cylinder, then adjust jet, intake and exhaust valves.
7. Before installing cylinder head cover, ensure sealant is applied to the top of the semi-circular packing. Install cylinder head cover and tighten mounting bolts to 55 INCH lbs. (6 N.m).

2.6L W/O Jet Valves

1. On 2.6L engines, perform valve adjustments after overhaul or service procedures. Cylinder head bolts must be tighten with engine hot prior to valve adjustment.
2. Start and warm engine to operating temperature. Remove cylinder head cover. Tighten cylinder head bolts to 75 ft. lbs. (103 N.m) in the proper sequence. (Scheme 1)
3. Position piston on TDC. Loosen valve adjuster lock nut. Using feeler gauge, measure clearance between adjusting screw and valve stem. Adjust valve clearance to specification. See VALVE CLEARANCE SPECIFICATIONS table.
4. Once proper clearance is obtained, tighten adjusting screw lock nut while holding adjusting screw.

VALVE CLEARANCE SPECIFICATIONS (1)

DISTRIBUTOR

The 2.2L engine is equipped with the Chrysler Motors Hall Effect Electronic Spark Advance (ESA) Ignition system. The 2.6L engine is equipped with the Mitsubishi Electronic Ignition System (EIS).

The only adjustments that can be made to either system are initial ignition timing and spark plug gap.

2.2L Firing Order & Timing Marks. Scheme 3

2.6L Firing Order & Timing Marks. Scheme 4

2.2L & 2.6L

1. Connect power timing light to No. 1 cylinder. If a magnetic probe timing light is used, refer to equipment manufacturer's instruction for proper hookup. Use a 10 degree offset when required.
2. Connect tachometer to engine. Turn off all lights and accessories. Warm engine to normal operating temperature. With engine off fast idle, momentarily open throttle and release to ensure linkage does not bind and idle speed screw is against the stop.
3. On 2.2L engines equipped with carburetor switch, connect jumper wire between carburetor switch and ground. Disconnect and plug vacuum hose at Spark Control Computer vacuum transducer.
4. On 2.2L Caravan, Voyager and Mini Ram Van, disconnect and plug vacuum hose at Spark Control Computer. Disconnect carburetor 6-way electrical connector, remove Violet/Purple wire and reconnect connector.
5. On 2.6L engines, disconnect and plug vacuum hose at distributor. Some models may contain 2 vacuum hoses at the distributor which must be disconnected.
6. Ensure engine is operating at or below curb idle RPM. If not, adjust curb idle screw. See HOT (SLOW) IDLE RPM in this article.
7. On 2.2L engines, aim power timing light at timing hole in bell housing. On 2.6L engines, aim power timing light at front crankshaft pulley or read magnetic timing unit.
8. If timing is not within plus or minus 2 degrees of specification, loosen distributor hold-down bolt and rotate distributor until specified timing is reached. See IGNITION TIMING SPECIFICATIONS table.
9. Recheck timing after distributor hold-down bolt has been tightened. When timing is acceptable, recheck curb idle RPM. If adjustment is necessary, readjust RPM and recheck timing. Unplug and reconnect vacuum hoses and reconnect electrical wire for 6-way connector (if necessary). If curb idle RPM is not within 50 RPM, readjust curb idle RPM.

IGNITION TIMING SPECIFICATIONS (1)

ELECTRONIC SPARK ADVANCE (ESA) CHECK

1. Ensure ignition initial timing is correct. Operate engine to obtain normal operating temperature. Check that temperature sensor is connected and operating properly.
2. Remove and plug vacuum hose at vacuum transducer. Connect an auxiliary vacuum supply to vacuum transducer. Apply 16 in. Hg of vacuum to vacuum transducer.
3. Raise engine speed to 2000 RPM, wait one minute and note timing specification. Advance specifications are in addition to initial timing. See ELECTRONIC SPARK ADVANCE SPECIFICATIONS table.
4. If specified readings are not obtained, see DISTRIBUTORS & IGNITION SYSTEMS for further test procedures. Computer may require replacement if proper specifications are not obtained.

ELECTRONIC SPARK ADVANCE SPECIFICATIONS (1) (DEGREES BTDC @ 2000 RPM)

HOT (SLOW) IDLE RPM

Note. 2.2L engines with A/C are equipped with a solenoid kicker. It is not necessary to adjust A/C idle speed but kicker operation should be checked.

A/C Solenoid Kicker Test (2.2L)

1. Operate engine at normal operating temperature. Position temperature control lever to the coldest position and turn on A/C. Solenoid kicker plunger should move in and out as A/C compressor clutch cycles.
2. Air cleaner may require removal to inspect plunger operation. If plunger does not operate, inspect solenoid kicker system for vacuum leaks in hoses. Check operation of vacuum solenoid. Replace solenoid kicker if no problems are found and solenoid kicker still does not operate.

CURB IDLE RPM

Note. Ensure ignition timing is correct before adjusting idle speed.

1. Turn off all lights and accessories. Apply parking brake and place transaxle in Neutral. Connect tachometer to engine. Start engine and operate on lowest speed step of fast idle cam. Engine must be at normal operating temperature. Return to idle, then shut off engine.
2. Unplug connector at radiator fan and install a jumper wire so fan operates continuously. Disconnect PCV valve from crankcase vent module and allow valve to draw in underhood air.
3. On all models, disconnect and plug vacuum hose from the solenoid kicker. Start engine and allow to idle for at least 2 minutes. Note curb idle speed.
4. Check idle speed against specification listed. See 2.2L IDLE SPEED SPECIFICATION table. Adjust idle speed to specified RPM using idle speed screw on top of solenoid kicker. (Scheme 5) 2.2L IDLE SPEED SPECIFICATION Engine (RPM) M/T Engine (RPM) A/T 850 900
5. Reconnect PCV valve and solenoid kicker vacuum hose. Normal idle speed may change slightly from the idle set RPM. DO NOT readjust idle speed. Remove jumper wire from radiator fan connector. Turn off engine and remove tachometer.

Scheme 5

Scheme 6

1. Ensure engine timing is correctly set. Apply parking brake and place transaxle in Neutral. Disconnect radiator cooling fan. Connect tachometer to engine.
2. On all models except A/C equipped models, operate engine until normal operating temperature is reached. Open throttle and let engine run at 2500 RPM for 10 seconds, then return to idle.
3. After 2 minutes at idle, note idle speed. See 2.6L IDLE SPEED SPECIFICATION table. If idle speed is not to specification, adjust idle speed screw. (Scheme 6)
4. On models with A/C, start engine and operate at 2500 RPM for 10 seconds. Return to idle and allow engine to idle for 2 minutes. NOTE: The A/C compressor clutch cycles on and off. Ensure clutch is engaged while adjusting idle-up adjusting screw.
5. Turn A/C on and set to coldest temperature. With compressor running, adjust engine to 900 RPM by turning idle-up screw. (Scheme 7)
6. On both A/C and non-A/C equipped engines, turn engine off, reconnect cooling fan and disconnect tachometer.

Scheme 7

2.6L IDLE SPEED SPECIFICATION

1. Shut off engine. Rotate throttle stop screw counterclockwise until it is clear of throttle lever.
2. Rotate throttle stop screw clockwise until it just contacts the throttle lever. Rotate throttle stop screw an additional 1/4 turn.

1. Ensure that ignition timing is adjusted to specification. Place transaxle in Neutral and apply parking brake. Operate engine to obtain operating temperature. Ensure that all accessories are off.
2. Ground the idle stop carburetor switch with a jumper wire. Remove the Red wire from 6-way connector on the carburetor side of connector.
3. If necessary, adjust throttle stop screw to obtain proper engine speed. (Scheme 5) Engine speed should be adjusted to 700 RPM for all models. Reconnect wire at connector and remove jumper wire.

IDLE MIXTURE

Note. Idle mixture adjustment is not part of a regular tune-up. DO NOT adjust mixture unless carburetor has been disassembled or vehicle fails emissions testing.

Mixture Screw Plug Removal - 2.2L

1. Remove air cleaner crossover. Remove canister purge and PCV vacuum hoses. Locate and center punch a mark 1/4" (6.35 mm) from the end of mixture screw housing. (Scheme 8)
2. Drill through outer section of housing using a 3/16" drill bit. Mixture screw plug should drop out. If not, use a small drift punch to remove plug. DO NOT allow drift to contact mixture screw.
3. Reinstall vacuum hoses and air cleaner crossover. Perform necessary adjustments and install new mixture screw plug.

Scheme 8

1. Remove impact plate (if equipped). (Scheme 9) Remove vacuum connector from high altitude compensator (HAC) fitting on carburetor (if equipped).
2. Use an 8" long by 1/4" diameter drill bit for drilling procedure. Drill out mixture screw plug. Drill bit must be held at the 11 o'clock position. (Scheme 10)

Scheme 9

Scheme 10

Note. The propane enrichment procedure should only be used when idle defect still exists after normal diagnosis. Check ignition timing, idle speed, vacuum hoses and wiring before performing this procedure.

Propane Enrichment Procedure (2.2L)

1. Apply parking brake and place transaxle in Neutral. Turn off all lights and accessories. Connect tachometer to engine. Remove mixture screw plug. Operate engine at normal operating temperature at least 5 minutes to fully stabilize engine idle RPM.
2. Disconnect cooling fan. Install jumper wire to obtain continuous operation of the cooling fan. Remove PCV valve from crankcase and allow to draw underhood air. Disconnect and plug EGR vacuum hose.
3. Disconnect and plug vacuum hose to the solenoid kicker. Disconnect and plug vacuum hose located on the 3-way connector for the air cleaner heated door air sensor. Install propane supply hose in place of the removed vacuum hose. WARNING: Ensure propane bottle valves are closed, bottle is upright and located in a safe place to prevent personal injury.
4. Open propane bottle main valve. With air cleaner installed, slowly open propane metering valve until maximum engine RPM is reached. Carefully adjust metering valve to obtain maximum steady RPM. NOTE: Carefully adjust metering valve. Excessive propane will cause engine speed to decrease.
5. Excessively rich idle mixture will also decrease engine RPM with any amount of propane. Rotate idle mixture screw inward approximately 1/2 turn and repeat step 4).
6. Adjust idle speed screw on top of solenoid kicker to specified RPM with propane valves opened. See 2.2L PROPANE ENRICHMENT IDLE SPEED table. Adjust propane metering valve to obtain highest engine RPM.
7. If maximum RPM has changed, readjust idle speed to specification. Turn off propane main valve and allow engine speed to stabilize. With air cleaner installed, use an Allen wrench to slowly adjust idle mixture screw to specified idle set RPM. (Scheme 8)
8. Allow engine to stabilize between adjustments. Turn on propane main valve. Adjust metering valve to obtain the highest RPM. If highest engine speed is more than 25 RPM of specified propane RPM, repeat steps 6) and 7) until proper propane idle RPM is obtained.
9. Turn off propane bottle valves. Remove supply hose and reinstall vacuum hose connection. Remove test equipment and fan jumper wire. Reconnect vacuum lines and install new mixture screw plug. Install impact plate (if equipped).

Note. Curb idle speed may differ from the idle set RPM. This is normal and curb idle speed should not be readjusted.

2.2L PROPANE ENRICHMENT IDLE SPEED

Note. Use idle RPM specification listed on the Emissions Control Label.

Propane Enrichment Procedure (2.6L)

1. Apply parking brake and place transaxle in Neutral. Turn off all lights and accessories. Connect tachometer to engine. Warm engine to normal operating temperature. Disconnect radiator fan.
2. Operate engine to obtain normal operating temperature. Allow engine to idle at least 2 minutes to fully stabilize engine idle RPM. Detach fresh air duct from air cleaner. WARNING: Ensure propane bottle valves are closed, bottle is upright and located in a safe place to prevent personal injury.
3. Install propane supply hose approximately 4" into air cleaner snorkel. Open propane main valve. Slowly open propane metering valve until highest engine RPM is reached. NOTE: Carefully adjust metering valve. Excessive propane will cause engine speed to decrease.
4. Excessively rich idle mixture will also decrease engine RPM with any amount of propane. Rotate idle mixture screw inward approximately 1/2 turn and repeat step 3).
5. While propane is flowing, adjust idle speed screw to specified propane RPM. See Emissions Label for proper specification. Adjust propane metering valve to obtain highest engine RPM.
6. If maximum RPM has changed, readjust idle speed screw to obtain the specified RPM. With propane main valve turned off, allow engine speed to stabilize.
7. Slowly adjust mixture screw to obtain proper idle RPM. Allow the engine idle speed to stabilize between adjustments. Open propane main valve.
8. Adjust metering valve to obtain highest engine RPM. If highest speed exceeds idle speed more than 25 RPM, repeat steps 3) through 8). Turn off propane valves. Remove propane hose and reinstall air duct to air cleaner. Install new mixture screw plug. Reconnect cooling fan and remove tachometer.

Scheme 11

1. Ensure ignition timing is correct. Apply parking brake and place transaxle in Neutral. Turn off all lights and accessories. Connect tachometer to engine. Warm engine on slowest step of fast idle cam. Return to curb idle and stop engine.
2. Remove connector from radiator fan and connect jumper wire so fan will operate continuously. Remove PCV valve from crankcase vent module and allow valve to draw underhood air. Remove and plug vacuum hose at solenoid kicker.
3. Disconnect and plug EGR vacuum hose. Start engine and slightly open throttle. Place fast idle adjusting screw on slowest step of fast idle cam. (Scheme 11) Allow engine speed to stabilize.
4. With choke fully open, adjust fast idle speed to specified RPM using fast idle adjusting screw. See 2.2L FAST IDLE SPEED table. Return to engine to curb idle. Position adjusting screw on slowest step of fast idle cam and note fast idle RPM. FAST IDLE SPEED Application Man. Trans. Engine RPM Auto. Trans. Engine RPM 2.2L (1) 1700 1850 (1) On Dakota models adjust to 1750 RPM.
5. Readjust fast idle speed if not within specification. Turn off engine and remove tachometer. Reconnect EGR hose, PCV valve and solenoid kicker. Remove jumper wire and reconnect radiator fan.

1. Ensure ignition timing is correct. Apply parking brake and place transaxle in Neutral. Shut off lights and accessories. Install tachometer on engine.
2. Disconnect and plug vacuum advance hose at distributor. Some distributors may have 2 vacuum hoses which must be disconnected and plugged. Operate engine until radiator fan operates.
3. Once radiator fan turns off, disconnect radiator fan. Open throttle slightly and install Cam Follower Spacer (C-4812) on the cam follower pin. (Scheme 12)
4. Release throttle lever and adjust fast idle speed to specification listed on the Emissions Label in the engine compartment. (Scheme 7) Turn off engine. Remove cam follower spacer and tachometer. Reconnect radiator fan. Install vacuum advance hose.

Scheme 12

AUTOMATIC CHOKE

All models are equipped with nonadjustable choke covers.

CHOKE VALVE SHAFT

1. To prevent choke from sticking due to gum deposits on shaft, spray Mopar Combustion Chamber Conditioner (4318001) onto choke shaft where it passes through air horn. NOTE: Service choke valve shaft, fast idle cam and pivot pin every 30,000 miles or every 12 months, whichever comes first.
2. Move choke blade back and forth to distribute solvent. Apply solvent to fast idle cam and pivot pin to remove dirt, oil and other deposits which may cause sticking or erratic motion.

1. With ignition off, connect a jumper wire between battery positive terminal and choke heater connection. Remove air cleaner and note choke plate. Choke plate should fully open within 5 minutes when vehicle is located inside service garage.
2. Electrical current is supplied to the choke through the oil pressure switch. A minimum oil pressure of 4 psi (.28 kg/cm 2 ) is required to close the contacts in the oil pressure switch and supply voltage to the choke heater.

Note. The choke housing is attached to carburetor with tamper-proof screws. Thermostat setting is not adjustable.

FUEL PUMP

The mechanical fuel pump is driven by an eccentric cam on accessory drive shaft. Incorporated in the fuel pump is an integral vapor separator to aid hot weather performance.

VACUUM TEST

Disconnect inlet and outlet fuel lines from fuel pump. Install vacuum gauge to inlet fitting. Crank engine for 10 seconds and note vacuum reading. Replace fuel pump if vacuum reading does not develop a minimum of 10 in. Hg of vacuum.

PRESSURE TEST

Connect a 0-15 minimum range pressure gauge to the fuel pump outlet fitting. Using starter motor, turn engine over several times and observe gauge. Replace fuel pump if pressure specified in the FUEL PUMP SPECIFICATIONS table is not obtained.

FUEL PUMP SPECIFICATIONS

All 2.2L engines are equipped with Chrysler Motors Hall Effect Electronic Spark Advance (ESA) Ignition systems. All 2.6L engines are equipped with Mitsubishi Electronic Ignition systems.

The only adjustments that can be made to either system are initial ignition timing and spark plug gap.

TOTAL SPARK ADVANCE SPECIFICATIONS

IGNITION COIL

IGNITION COIL RESISTANCE (OHMS @ 70-80°F (21-27°C))

EMISSION CONTROL

For information on emission control systems, see EMISSION section.

FUEL SYSTEMS

CARBURETOR APPLICATION

BATTERY

BATTERY SPECIFICATIONS

STARTER

The 2.2L engine uses a Bosch double gear reduction starter. The 2.6L engine uses a Mitsubishi double gear reduction starter.

Note. When performing cranking amperage draw test, ensure engine is at operating temperature. Extremely heavy oil or tight engine will increase starter amperage draw. Standard cranking amperage draw is 150-210 amps.

STARTER SPECIFICATIONS

ALTERNATOR

ALTERNATOR SPECIFICATIONS (WITH EXTERNAL VOLTAGE REGULATOR)

ALTERNATOR SPECIFICATIONS (WITH INTERNAL VOLTAGE REGULATOR)

ALTERNATOR REGULATOR

Alternators with external regulator are equipped with Chrysler Motors Electronic Voltage Regulator.

REGULATOR OPERATING VOLTAGE

SERVICE INTERVALS

REPLACEMENT & SERVICE INTERVALS (1)

BELT ADJUSTMENT

BELT ADJUSTMENT (1)

CAPACITIES

FLUID CAPACITIES

SYSTEM REFRIGERANT CAPACITIES