2.6l Carburetor Cec Diagnosis — Dodge Aries I (1981-1989)

DESCRIPTION

The computerized engine control system is used on California and Federal 2.6L engines equipped with Mikuni 2-barrel carburetors. The carburetor has 3 air/fuel solenoids and a throttle opener to control air/fuel mixture for all operating conditions. The electronic control unit (ECU) monitors several sensors and switches on the engine to adjust fuel flow to maintain a 14:1 air/fuel ratio.

When certain operating conditions are met, the ECU goes into closed loop mode. The ECU monitors throttle position (except idle), idle position, engine speed, coolant temperature, intake air temperature and exhaust oxygen content. The ECU uses this information to control carburetor solenoid duty cycle, throttle opener, deceleration spark control and air conditioner control.

ELECTRONIC CONTROL UNIT (ECU)

The ECU, located in the passenger compartment, is connected to the remainder of the system by 13-wire and 7-wire connectors. The ECU receives input signals from sensors and switches, and sends output signals to the engine controls. These output signals are used by ECU to control air/fuel ratio, secondary air, deceleration spark and throttle opener system.

Enrichment Solenoid

When high fuel operation such as uphill acceleration, or warm-up operation is required, the ECU opens enrichment solenoid. This solenoid provides additional fuel to the main fuel system. ECU operates this solenoid at a preset duty cycle. (Scheme 60)

Deceleration Solenoid

When ignition switch is in "OFF" position, deceleration solenoid valve is closed to prevent engine dieseling. The solenoid will also close under certain deceleration conditions to reduce HC emissions and to improve fuel economy. (Scheme 60)

Enrichment and Fuel Shut-Off (Deceleration) Solenoid. Scheme 60

Scheme 60: Enrichment and Fuel Shut-Off (Deceleration) Solenoid

Jet Mixture Solenoid

The jet mixture solenoid supplies fuel to the jet mixture portion of the carburetor. The ECU controls this solenoid in response to signals from oxygen sensor. (Scheme 61)

When oxygen sensor detects a lean condition, ECU increases the jet mixture solenoid duty cycles to enrich the mixture. When the oxygen sensor detects a rich mixture, ECU decreases the jet mixture solenoid duty cycles to lean out the mixture.

Jet Mixture Solenoid. Scheme 61

Scheme 61: Jet Mixture Solenoid

Coolant Temperature Sensor

The coolant temperature sensor is located on the intake manifold. This sensor provides ECU with engine operating temperature information, necessary to control fuel delivery and secondary air management.

Engine Speed Sensor

The ECU receives engine speed information from the ignition coil. This information is used to control air/fuel ratio, secondary air, deceleration spark and throttle opener controls.

Idle Position Switch

This switch is mounted on the carburetor. When the throttle blade is at the closed or idle position, this switch is "ON". ECU uses this information to control air/fuel ratio and secondary air control, as well as to adjust idle speed.

Intake Temperature Switch

This switch is located in the air cleaner. This sensor provides ECU with intake air temperature information. ECU uses this information to control air/fuel ratio.

Oxygen Sensor

This sensor is located on the exhaust manifold. This sensor measures the oxygen content of the exhaust gases, and signals the ECU. ECU uses this information to control air/fuel ratio during closed loop operation.

Throttle Position Sensor (TPS)

The TPS, a potentiometer mounted on carburetor, provides ECU with carburetor throttle angle position. ECU uses information to control air/fuel ratio and secondary air control.

Chrysler Corp. 2.6L ECU Wiring Diagram. Scheme 62

Scheme 62: Chrysler Corp. 2.6L ECU Wiring Diagram

BASIC TESTING INFORMATION

Complete No Start (NS), Cold Driveability (COLD DR) and Warm Driveability (WARM DR) Tests in the order shown. Cold Driveability Tests (COLD DR) must begin with engine cold, while Warm Driveability Tests (WARM DR) must begin with engine warm.

NO START TESTS INFORMATION

Because of a limited amount of space for titles, NO START tests will be referred to as NS. This allows for a more complete description of the test to be displayed on the menu.

NS1 - IGNITION SYSTEM TESTS

Remove spark plug wire from plug. Hold wire terminal 1/4" from good ground, and crank engine. If good spark occurs, proceed to «NS2 - FUEL SYSTEM TESTS»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__ns2-fuel-system-tests) . If no spark or weak spark occurs, remove ignition coil wire from distributor. Hold coil wire terminal 1/4" from good ground, and crank engine. If good spark occurs, problem is in distributor rotor, cap or spark plug wires.
If no spark occurred, remove coil wire from coil. Connect ohmmeter leads to both ends of coil wire. Resistance should read 250-600 ohms per inch (3000-7000 ohms per foot). If not, replace coil wire. If resistance was okay, connect voltmeter positive lead to coil positive terminal. Attach negative lead securely to a good ground. Turn ignition switch to "RUN" position. Voltage should be within 1 volt of battery voltage. If not, repair wire to ignition switch.
If voltage was correct in step 2), move voltmeter positive lead to the coil negative terminal. Voltmeter should again indicate within 1 volt of battery voltage. If voltage is correct, proceed to step 6).
If voltage was not correct in step 3), turn ignition switch off. Remove 2 wires from coil negative terminal. With negative lead still grounded, again connect voltmeter positive lead to coil negative terminal. Turn ignition switch to "RUN" position. Voltmeter should read within 1 volt of battery voltage. If so, proceed to next step; if not, replace ignition coil.

NS2 - FUEL SYSTEM TESTS

Remove air cleaner cover. Move throttle linkage by hand several times. Check for fuel spraying from accelerator pump nozzle. If no fuel is spraying, proceed to step 2). If fuel is spraying, check for fuel-fouled spark plugs. If wet with fuel, clean and reinstall. If spark plugs are dry, CHECK TIMING for 0-16°. If okay, check valve timing. If not, set timing to 10° during cranking. If engine starts, reset timing to specifications. If engine does not start, check valve timing.
Remove fuel hose from carburetor. Place hose in a clear container. Have assistant crank engine. A pulsating stream of fuel should flow into container. If so, repair inlet circuit of carburetor. If fuel flow was not satisfactory, remove hose at fuel filter that leads to fuel pump. Connect a vacuum gauge to disconnected hose. Have an assistant crank engine for 10 seconds. Vacuum should increase from 0 in. Hg during cranking. If not, replace fuel pump.
If vacuum was okay in step 2), remove vacuum gauge from hose. Reconnect hose to fuel filter. Remove fuel inlet hose at fuel filter. Connect vacuum gauge to inlet nipple of filter. Again, have an assistant crank engine for 10 seconds. Vacuum should increase from 0 in. Hg during cranking.
If so, vacuum is okay. Check for plugged fuel lines back to tank. Also check fuel tank venting and in-tank filter. If vacuum was not okay in step 3), replace fuel filter.
Turn ignition switch off. Reconnect Black/Yellow wire to coil negative terminal. Connect voltmeter positive lead to coil negative terminal. Turn ignition switch to "RUN" position. Voltmeter should read within 1 volt of battery voltage. If so, but engine will not start, replace ignitor assembly inside distributor. If voltage is not satisfactory, replace ECU.
If reading in step 3) was within 1 volt of battery voltage, disconnect voltmeter and turn ignition switch off. Connect ohmmeter leads to coil positive and negative terminals. Primary resistance should measure less than 1.2 ohms. If not, replace ignition coil.
If primary resistance was correct, remove secondary wire from coil. Connect ohmmeter leads to coil negative terminal and secondary terminal. Secondary resistance should measure 8,000-11,000 ohms. If not, replace ignition coil. If secondary resistance was correct, proceed to step 8).
Remove distributor cap and rotor. Connect ohmmeter leads to pick-up coil terminals. Pick-up coil resistance should be 900-1200 ohms. If not, replace pick-up coil.
If pick-up coil resistance was satisfactory, remove Light Blue and Black/White igniter wires from ignition coil. Connect ohmmeter leads, in turn, to both ends of each wire. Continuity should exist. If no continuity is indicated, repair open circuit of harness. If continuity exists, but engine still will not start, replace igniter in distributor.

COLD DRIVEABILITY TEST INFORMATION

Because of a limited amount of space for titles, COLD DRIVEABILITY tests will be referred to as COLD DR. This allows for a more complete description of the test to be displayed on the menu screen.

Note. The following tests must begin with engine cold. Conduct tests in order given. Check first that all electrical, fuel and hose connections are properly made.

COLD DR1 - CHOKE POSITION

Remove air intake housing. If choke plate is fully or almost fully closed, proceed to next test. If not, check for sticking linkage or repair carburetor.

Scheme 63

Scheme 63: COLD DR2 - HEATED AIR INTAKE

Remove outside air duct from air cleaner. Remove vacuum hose from heated air door diaphragm. Connect an auxiliary vacuum supply to the diaphragm, and apply 10 in. Hg vacuum. Check position of heated air door in air cleaner snorkel. Vacuum should hold and heated air door should close to outside air. (Scheme 63): Heated Air Door Diaphragm
If vacuum does not hold, repair or replace parts as required. If results in step 1) were satisfactory, remove air intake housing. Remove both vacuum hoses from heater air intake sensor.
Connect auxiliary vacuum supply to one nipple of sensor, and plug the other. Apply 10 in. Hg vacuum. Vacuum should hold at temperatures of 85°F or less. If not, replace heated air intake sensor. If okay, proceed to next test.

Scheme 64

Scheme 64: COLD DR3 - COOLANT SENSOR

Connect voltmeter negative lead to a good ground. Attach positive lead to cavity No. 12 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Voltmeter should read 3-5.5 volts with engine cold; 1-2 volts at room temperature and 0-1 volt with engine warm. (Scheme 64): 13-Wire ECU Connector
If okay, go to «COLD DR4 - AIR INTAKE TEMPERATURE SENSOR»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage was incorrect in step 1), turn ignition switch off. Disconnect connector from coolant sensor. Connect ohmmeter leads to sensor terminals. Resistance should be 3,000-17,000 ohms with engine cold; 1000-3000 ohms at room temperature; and 100-1000 ohms with engine warm. If not, replace sensor.
If resistance is okay, disconnect 13-wire connector from ECU. Connect ohmmeter leads to cavity Nos. 2 and 12. Resistance should be as indicated in step 2). If resistance is okay, replace ECU. If resistance is not okay, repair open wires from coolant sensor to ECU.

Scheme 65

Scheme 65: COLD DR4 - AIR INTAKE TEMPERATURE SENSOR

Scheme 66

Connect voltmeter negative lead to ground. Connect voltmeter positive lead to cavity No. 4 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Voltmeter should read 3-5.5 volts with engine cold; 1-2 volts at room temperature and 0-1 volt with engine warm. (Scheme 65): 13-Wire ECU Connector (Scheme 66): Ohmmeter
If okay, proceed to «COLD DR5 - THROTTLE POSITION SENSOR»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If not okay, connect an ohmmeter between terminals of sensor connector. Ohmmeter should read 6000 or more ohms with engine cold, 1300-2500 ohms at room temperature, and 100-1300 ohms with engine warm. If resistance is as specified, proceed to step 3). If resistance is not to specification, replace air intake temperature sensor.
Reconnect air temperature sensor connector. Disconnect 13-wire ECU connector. Connect ohmmeter leads to cavity Nos. No. 2 and 4. Ohmmeter should read as in step 2). If resistance is correct, replace ECU. If resistance is incorrect, repair open or shorted wires from air intake temperature sensor to ECU.

Scheme 67

Scheme 67: COLD DR5 - THROTTLE POSITION SENSOR

Connect voltmeter negative lead to a good ground, and attach its positive lead to cavity No. 13 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Check voltage with the throttle closed and open. Voltage should be 0-1 volts with throttle closed; 3-5.5 volts with throttle wide open.
If voltage is as specified, go to «COLD DR6 - THERMO VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr6-thermo-valve). If voltage is not to specifications, turn ignition switch off and disconnect 4-wire carburetor connector. Connect ohmmeter leads to Orange and Light Green/Red wires. Resistance should be 3500-6500 ohms with throttle closed and 100-1000 ohms with throttle wide open. If not, replace throttle position sensor. (Scheme 67): 13-Wire Connector
If resistance was okay, connect ohmmeter leads to cavity Nos. 3 and 13 of 13-wire connector. Resistance should be 3500-6500 ohms with throttle closed and 100-1000 ohms with throttle wide open. If okay, replace ECU. If not okay, repair open wires to throttle sensor.

COLD DR6 - THERMO VALVE

Disconnect vacuum hose connector from thermo valve. Connect an auxiliary vacuum supply to each nipple of thermo valve. Attempt to apply vacuum. Vacuum should not hold at any nipple with coolant below 150°F. If it does not hold, go to COLD DR7 - CHOKE POSITION FAST IDLE SPEED. If vacuum holds, replace thermo valve.

COLD DR7 - CHOKE POSITION FAST IDLE SPEED

Remove air intake housing. Connect tachometer to engine. Note position of choke plate opening. Start engine and observe choke plate opening. Opening should be greater after engine is started and engine speed should be higher than curb idle speed. If both requirements are met, proceed to next test; if not, repair carburetor as required.

COLD DR8 - FOULED SPARK PLUGS

Start engine. If engine runs smoothly, go to «COLD DR9 - SECONDARY IGNITION SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr9-secondary-ignition-system) test below. If not, turn engine off and remove spark plugs.
If plugs are wet with fuel (not just black in color), clean and reinstall. Check for gas in crankcase and change oil if required. If plugs are not wet with fuel, proceed to next test.

COLD DR9 - SECONDARY IGNITION SYSTEM

Connect oscilloscope to engine. Start engine and follow manufacturer's test pattern analysis. If pattern is okay, proceed to COLD DR10 - JET MIXTURE VALVE CIRCUIT test below. If scope pattern is not correct, repair secondary ignition system.

Scheme 68

Scheme 68: COLD DR10 - JET MIXTURE VALVE CIRCUIT

Connect voltmeter negative lead to ground. Connect voltmeter positive lead to cavity No. 1 of ECU 7-wire connector. Start engine. At temperatures below 126°F, voltmeter should indicate a steady voltage of less than 1 volt below battery voltage. (Scheme 68): ECU 7-Wire Connector
If voltage is within 1 volt of battery voltage, replace ECU. If voltage is 0-1 volt, disconnect 7-wire ECU connector. If voltage is now within 1 volt of battery voltage, replace ECU. If still 0-1 volt, go to «COLD DR12 - JET MIXTURE VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage was okay in step 1), proceed to «COLD DR11 - ENRICHMENT VALVE CIRCUIT»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis) below.

Scheme 69

Scheme 69: COLD DR11 - ENRICHMENT VALVE CIRCUIT

With engine running, connect voltmeter positive lead to cavity No. 5 of ECU 7-wire connector. Attach negative lead to ground. At temperatures below 126°F, voltmeter should read a steady voltage of less than 1 volt below battery voltage. (Scheme 69): ECU 7-Wire Connector
If voltage is within 1 volt of battery voltage, replace ECU. If voltage is 0-1 volt, disconnect 7-wire connector. If voltage is now within 1 volt of battery voltage, replace ECU. If still 0-1 volt, proceed to «COLD DR13 - ENRICHMENT VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage was okay in step 1), proceed to «COLD DR14 - BOWL VENT SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr14-bowl-vent-system).

Scheme 70

Scheme 70: COLD DR12 - JET MIXTURE VALVE

Turn ignition switch off. Disconnect carburetor 6-wire connector. Connect ohmmeter leads to Dark Green and Red/White wires leading to jet mixture valve. Ohmmeter should show continuity. If not, replace jet mixture valve. (Scheme 70): Carburetor 6-Wire Connector
If continuity is shown, connect voltmeter negative lead to a good ground. Connect positive lead to Dark Blue wire of carburetor harness connector. Turn ignition switch to "RUN" position. Voltage should read within 1 volt of battery voltage. If 0 volts are indicated, repair open Dark Blue wire to ignition switch. If voltage was okay, repair wire from cavity No. 1 of ECU 7-wire connector for an open or shorted condition.

Carburetor 6-Wire Connector. Scheme 71

Scheme 71: Carburetor 6-Wire Connector

Scheme 72

Scheme 72: COLD DR13 - ENRICHMENT VALVE

Scheme 73

Turn ignition switch off. Disconnect carburetor 6-wire connector. Connect ohmmeter leads to Dark Blue and Yellow/Orange wires leading to enrichment valve. Ohmmeter should show continuity. (Scheme 72): Carburetor 6-Wire Connector
If no continuity is indicated, replace enrichment valve. If continuity is indicated, connect voltmeter negative lead to ground. Connect positive lead to Dark Blue wire of carburetor harness connector. Turn ignition switch to the "RUN" position. (Scheme 73): Carburetor 6-Wire Harness Connector
Voltmeter should indicate within 1 volt of battery voltage. If no voltage is indicated, repair open Dark Blue wire to ignition switch. If voltage is okay, repair wire for cavity No. 5 of ECU 7-wire connector for open or shorted condition.

COLD DR14 - BOWL VENT SYSTEM

Remove bowl vent hose from carburetor and from canister. Blow lightly into hose. Air should pass through hose. If air does not pass, clear hose or replace external bowl vent valve.
If air passes through hose, start engine and blow lightly into hose. Air should not pass through hose. If air passes through hose, check and repair, as necessary, the electrical circuit to bowl vent valve. If okay, replace external bowl vent valve.
If air did not pass through hose in step 2), proceed to Cold DR15 below.

COLD DR15 - BASIC IGNITION TIMING

Connect tachometer and power timing light to engine. Disconnect and plug vacuum hose at distributor. Warm engine to normal operating temperature. Check that idle speed is 700-900 RPM. Adjust if necessary.
Ignition timing should be within 2° of specification shown on emission label. If so, proceed to Cold DR16 below. If timing is not within proper range, adjust as necessary.

COLD DR16 - MECHANICAL ADVANCE

If basic ignition timing was okay, raise engine speed to 3800 RPM. Timing should be 11-19° BTDC (preferably 15° BTDC) on vehicles with distributor No. MD067134 ; 15-23° BTDC on vehicles with distributor No. XD094020 .
If not within specified range, remove distributor and check mechanical advance weights and springs. Repair as necessary. If okay, proceed to «COLD DR17 - VACUUM ADVANCE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr17-vacuum-advance) .

COLD DR17 - VACUUM ADVANCE

Return engine to idle speed. Connect an auxiliary vacuum supply to distributor and apply 12 in. Hg vacuum. Timing should be 33-41° BTDC.
If timing is not to specifications, replace vacuum advance diaphragm. If timing is okay, proceed to «COLD DR18»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr18-propane-rpm) below.

COLD DR18 - PROPANE RPM

Turn off all lights and accessories. Connect a tachometer to engine. Disconnect radiator cooling fan, and warm engine to normal operating temperature. Turn ignition switch off. Disconnect the battery negative cable for 3 seconds and then reconnect it. Disconnect the oxygen sensor connector, and restart the engine.
Run engine for more than 2 minutes. Remove fresh air duct from air cleaner. Insert propane hose 4 inches into the air cleaner snorkel. Open propane main valve. Meter propane until maximum RPM is reached.
Engine speed should increase by 40-90 RPM. If such increase occurs, proceed to «COLD DR19»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__cold-dr19-fast-idle-rpm) below. If engine speed does not increase properly, adjust by propane assisted idle set procedures.

COLD DR19 - FAST IDLE RPM

Turn off all lights and accessories. Connect tachometer to engine and disconnect radiator cooling fan. Warm engine to normal operating temperature and continue running it for 2 more minutes.
Remove propane supply hose from air cleaner snorkel. Reconnect fresh air duct to air cleaner. Reconnect oxygen sensor system. Raise engine speed to 2500 RPM for 10 seconds and permit it to return to idle speed. Disconnect and plug vacuum hose at distributor.
Open throttle slightly and install special adjustment tool C-4812 . Wait 15 seconds for engine to stabilize. Fast idle speed should be within 850-1050 RPM. If not okay, adjust as necessary.

Note. By now you have determined all engine control systems are operating properly. Check engine vacuum, valve timing, and compression. Check cooling, exhaust, and PCV systems. Check fuel pump pressure volume, torque converter stall speed, power brake booster. Also check fuel for contamination and check carburetor.

WARM DRIVEABILITY TEST INFORMATION

Because of a limited amount of space for titles, WARM DRIVEABILITY tests will be referred to as WARM DR. This allows for a more complete description of the test to be displayed on the menu screen.

Note. The following tests must begin with a warm engine. Conduct tests in order shown.

Scheme 74

Scheme 74: WARM DR1 - CARBURETOR SWITCH

Connect voltmeter negative lead to ground. Connect positive lead to cavity No. 5 of ECU 13-wire connector. Turn ignition switch to "RUN" position, and open and close the throttle. (Scheme 74): ECU 13-Wire Connector
When the throttle is at wide open, voltmeter should indicate 9-11 volts. When closed, it should read 0-1 volt. If okay, go to «WARM DR2 - COOLANT SENSOR»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If 9-11 volts when throttle is closed, proceed to step 4).
If in step 2) no voltage was indicated, disconnect the carburetor switch connector. Voltmeter should read 9-11 volts. If so, replace carburetor switch. If 0-1 volt are indicated, check wire from carburetor switch to the ECU for a short to ground. If none is found, replace ECU.
Disconnect carburetor switch connector and ground it with a jumper wire. Voltmeter should read 0-1 volt. If so, replace carburetor switch. If 9-11 volts are indicated, repair open wire from switch to ECU.

Scheme 75

Scheme 75: WARM DR2 - COOLANT SENSOR

Connect voltmeter negative lead to a good ground. Attach positive lead to cavity No. 12 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Voltmeter should read 0-1 volt. (Scheme 75): 13-Wire ECU Connector
If okay, go to «WARM DR3 - AIR INTAKE TEMPERATURE SENSOR»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage was incorrect in step 1), turn ignition switch off. Disconnect coolant sensor connector. Connect ohmmeter between sensor terminals. Ohmmeter should indicate 100-1000 ohms. If not, replace coolant sensor.
If resistance was okay in step 2), reconnect connector to sensor. Disconnect 13-wire connector from ECU. Connect ohmmeter leads to cavity Nos. 2 and 12. Resistance should be 100-1000 ohms. If resistance is okay, replace ECU.
If no resistance was found in step 3), repair open wires from coolant sensor to ECU.

Scheme 76

Scheme 76: WARM DR3 - AIR INTAKE TEMPERATURE SENSOR

Scheme 77

Connect voltmeter negative lead to ground. Connect voltmeter positive lead to cavity No. 4 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Voltmeter should read 1-2 volts. (Scheme 76): 13-Wire ECU Connector
If correct, go to «WARM DR4 - THROTTLE POSITION SENSOR»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage was not okay, disconnect connector from air intake temperature sensor. Connect ohmmeter leads to terminals of sensor connector. Ohmmeter should read 100-1300 ohms. If resistance is incorrect, replace air intake temperature sensor. If resistance was okay, turn ignition switch off. Reconnect sensor connector. Disconnect 13-wire connector. Connect ohmmeter leads to cavity Nos. 2 and 4. (Scheme 77): Ohmmeter
Ohmmeter should read 100-1300 ohms. If resistance is correct, replace ECU. If resistance is incorrect, repair open or shorted wires from sensor to ECU.

Scheme 78

Scheme 78: WARM DR4 - THROTTLE POSITION SENSOR

Scheme 79

Connect voltmeter negative lead to a good ground, and attach its positive lead to cavity No. 13 of 13-wire ECU connector. Turn ignition switch to "RUN" position. Check voltage with throttle closed and open. Voltage should be 0-1 volt with throttle closed; 3-5.5 volts with throttle wide open. (Scheme 78): 13-Wire ECU Connector
If voltage reading is within specifications, proceed to «WARM DR5 - FUEL CUT-OFF SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage is not correct, disconnect 4-wire carburetor connector. Be sure ignition switch is off. Connect ohmmeter leads to Orange and Light Green/Red wires of carburetor connector. Measure resistance with throttle closed and wide open. With throttle closed, reading should be 3500-6500 ohms. With throttle wide open, reading should be 100-1000 ohms. (Scheme 79): Carburetor 4-Wire Connector
If resistance is incorrect, replace throttle position sensor. If reading is okay, check that ignition switch is still off. Reconnect carburetor 4-wire connector. Disconnect 13-wire connector from ECU. Connect ohmmeter leads to cavity Nos. 3 and 13.
Resistance should be the same as shown in step 2). If resistance is okay, replace ECU. If no resistance, repair open wires from throttle sensor to ECU.

Scheme 80

Scheme 80: WARM DR5 - FUEL CUT-OFF SYSTEM

With fuel cut-off (deceleration) solenoid connector connected, place ignition switch in "RUN" position. Connect voltmeter positive lead to solenoid connector. Attach negative lead to ground. Voltmeter should read within 1 volt of battery voltage. If not, repair open wire to ignition switch.
If voltage was okay, make sure solenoid ground wire is connected to carburetor. If so, replace fuel cut-off solenoid. Disconnect carburetor 6-wire connector. Make and break the connection several times. Listen for clicking of solenoid. It should occur every time connection is made and broken.
If solenoid clicks, proceed to «WARM DR6 - CHOKE POSITION»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr6-choke-position). 6. If solenoid does not click, turn ignition switch off. Reconnect carburetor 6-wire connector. Disconnect ECU 7-wire connector. Connect a jumper wire to ECU mounting stud. Turn ignition switch to "RUN" position. Connect other end of jumper wire to cavity No. 2 of 7-wire connector. Make and break this connection several times.
Solenoid should click each time connection is made and broken. If not, proceed to step 6). If so, check ECU. Connect voltmeter positive lead to cavity No. 7 or 8 of ECU 3-wire connector. Connect negative lead to cavity No. 6 of the same connector. Voltmeter should read within 1 volt of battery voltage. If so, replace ECU.
If 0-1 volt is indicated, move voltmeter negative lead to a good ground. If voltmeter now reads within 1 volt of battery voltage, repair open ECU ground wires. If voltmeter still reads 0-1 volt, repair open ignition feed wires to ECU.
With ignition switch in the "RUN" position and ECU 7-wire connector disconnected, disconnect jumper wire. Connect voltmeter negative lead to ground. Connect positive lead to cavity No. 2 of ECU 7-wire connector. Voltmeter should read within 1 volt of battery voltage. If so, replace fuel cut-off solenoid (deceleration solenoid valve).
If 0-1 volt was indicated, turn ignition switch off. Disconnect carburetor 6-wire connector. Connect ohmmeter leads to Dark Blue and Red fuel cut-off wires in the carburetor 6-wire connector. Some resistance should be indicated. (Scheme 80): Carburetor 6-Wire Connector
If so, check for ignition voltage to solenoid. If there is voltage, then repair open wire to cavity No. 2 of ECU 7-wire connector. If no resistance was indicated, replace fuel cut-off solenoid (deceleration solenoid valve).

WARM DR6 - CHOKE POSITION

Remove air intake housing. Start engine. If choke plate is fully open, proceed to Warm DR7 below. If not, repair carburetor.

Scheme 22: Carburetor

WARM DR7 - THERMO VALVE

Disconnect the vacuum hose connector from the thermo valve. Connect an auxiliary vacuum supply to each nipple. Try to apply vacuum. Vacuum should hold at each nipple. If it holds, proceed to Warm DR8 below. If vacuum does not hold, replace thermo valve.

WARM DR8 - EGR SYSTEM

Connect a tachometer to engine. Warm engine to normal operating temperature. Open sub EGR valve with your fingers. Engine speed should not drop. If engine speed is okay, proceed to «WARM DR9»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis) below.
If engine speed dropped in step 1), remove vacuum hose (leading to carburetor) at secondary EGR valve. Connect vacuum gauge to hose. Gauge should indicate 0-2 in. Hg. If vacuum is okay, replace EGR valve.
If vacuum was greater than 2 in. Hg, the throttle blade is open too far. Check basic timing and curb idle speed.

Scheme 81

Scheme 81: WARM DR9 - AIR CONTROL SYSTEM

Scheme 82

Scheme 83

Disconnect vacuum hose from secondary air control valve. Connect a vacuum gauge to hose, and start engine. Vacuum gauge should read manifold vacuum for approximately 1 minute and then drop to 0 in. Hg. If so, proceed to step 2). If vacuum reading is incorrect, proceed to step 3). (Scheme 81): Secondary Air Control Valve
With engine running and vacuum hose disconnected from secondary air control valve, disconnect air intake hose from secondary air control valve. Place your hand on valve's air intake port. If suction is felt, replace secondary air control valve. If no suction is felt, proceed to «WARM DR10 - SPARK CONTROL SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). (Scheme 82): Secondary Air Control Valve
With engine running for more than 1 minute, connect voltmeter negative lead to ground. Attach positive lead to cavity No. 4 of 7-wire ECU connector. Voltmeter should read within 1 volt of battery voltage. If voltage is okay, replace secondary air control solenoid. (Scheme 83): 7-Wire ECU Connector
If voltage was 0-1 volt in step 3), disconnect 7-wire ECU connector. If voltage is still 0-1 volt, proceed to step 5). If voltage is now within 1 volt of battery voltage, proceed to step 6).
Turn the ignition switch off. Disconnect 3-wire connector at secondary air control solenoid. Connect ohmmeter leads to two Blue wires of solenoid connector. Ohmmeter should show some resistance. If circuit is open, replace air control solenoid. If resistance is indicated, check for an open ignition feed wire to solenoid, and repair as necessary. If not open, repair wire to cavity No. 4 of 7-wire ECU connector for a short to ground.
Reconnect the 7-wire connector to the ECU. Connect voltmeter negative lead to ground. Connect positive lead to cavity No. 10 of 13-wire connector. Start the engine. Voltmeter should read at least 5 volts. If voltage is okay, replace the ECU. If 0 volts are recorded, repair open wire of cavity No. 10 leading to ignition coil negative terminal.

7-Wire Connector. Scheme 84

Scheme 84: 7-Wire Connector

Scheme 85

Scheme 85: WARM DR10 - SPARK CONTROL SYSTEM

Scheme 86

Using a tee, install a vacuum gauge in hose connected to distributor. Start engine. If vacuum gauge reads 0 in. Hg, proceed to step 4). If vacuum reading is higher than 0 in. Hg but not equal to manifold vacuum, carburetor throttle plate is open too much. Check basic timing and/or idle speed. (Scheme 85): Distributor
If vacuum gauge reads manifold vacuum, connect voltmeter negative lead to a good ground. With engine running, attach positive lead to cavity No. 2 of 7-wire ECU connector. Voltmeter should read 0-1 volt. If voltage is within 1 volt of battery voltage, replace or ECU. (Scheme 86): 7-Wire ECU Connector
If voltage is okay, turn ignition switch off. Disconnect 3-wire solenoid connector. Connect ohmmeter leads to Black wires of solenoid connector. Ohmmeter should show some resistance. If so, repair open wire to ECU. If no resistance was indicated, replace solenoid.
If vacuum gauge measured 0 in. Hg in step 1), connect a tachometer to engine. Raise engine speed to 2000 RPM. Vacuum gauge should read manifold vacuum. If vacuum measures okay, proceed to the «WARM DR11 - A/C IDLE UP SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis) test for air conditioned cars; or to «WARM DR12 - SECONDARY IGNITION SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr12-secondary-ignition-system) for vehicles without air conditioning.
If vacuum was not correct in step 4), connect voltmeter negative lead to ground. Attach positive lead to cavity No. 2 of 7-wire ECU connector. Slowly raise engine speed to 2000 RPM. Voltmeter should read within 1 volt of battery voltage.
If voltage is okay, check manifold vacuum supply to control solenoid. If okay, replace solenoid. If 0-1 volt was indicated, replace ECU.

Scheme 87

Scheme 87: WARM DR11 - A/C IDLE UP SYSTEM

Scheme 88

Scheme 89

Scheme 90

Connect tachometer to engine. Turn off all lights and accessories. Set A/C temperature selector switch to coldest position. Start engine and allow engine speed to stabilize. Place blower switch in the "ON" position.
Have an assistant push A/C button. Watch for movement of idle up vacuum diaphragm plunger, while A/C compressor clutch is engaged. (Scheme 87): A/C Vacuum Diaphragm NOTE: Since A/C clutch cycles on and off, make sure it is on when doing this test. If A/C clutch does not engage, DO NOT proceed with test until necessary A/C clutch repairs are made.
Diaphragm plunger should move upwards and increase engine RPM to specifications while A/C compressor clutch is engaged. If plunger movement and speed increase occurs properly, proceed to the «WARM DR12 - SECONDARY IGNITION SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr12-secondary-ignition-system) test. If plunger movement is okay, but speed does not increase, adjust as necessary.
If no plunger movement occurred in step 3), remove vacuum hose from A/C idle up vacuum diaphragm. Connect a vacuum gauge to the hose. Vacuum gauge should read at least 10 in. Hg when A/C clutch is engaged and 0 in. Hg when clutch is disengaged. (Scheme 88): A/C Vacuum Diaphragm
If vacuum is okay, replace idle up vacuum diaphragm. If vacuum is present all the time, replace idle up vacuum solenoid. If no vacuum is present, check vacuum supply to idle up vacuum solenoid. If vacuum is present at solenoid, remove connector from idle up vacuum solenoid. Reconnect Green wire to either solenoid terminal. Connect jumper wire between open terminal of solenoid and ground.
Vacuum gauge should indicate manifold vacuum. If vacuum is okay, repair open Blue/Orange wire of solenoid connector.
If no vacuum was present in step 6), remove connector from idle up vacuum solenoid. Connect voltmeter negative lead to ground. Attach positive lead to Green wire of solenoid connector. Check voltmeter while A/C clutch is engaged. Voltmeter should read within 1 volt of battery voltage. (Scheme 89): Solenoid Connector
If voltage is okay, replace idle up vacuum solenoid. If there is no voltage, connect voltmeter negative lead to ground. Connect positive lead to cavity No. 3 of 7-wire ECU connector. Voltage should read within 1 volt of battery voltage. If not, replace the ECU. (Scheme 90): 7-Wire ECU Connector
If voltage is correct, repair open wire from cavity No. 3 to solenoid.

WARM DR12 - SECONDARY IGNITION SYSTEM

Connect oscilloscope to engine. Start engine and follow manufacturer's test pattern analysis. If pattern is okay, go to WARM DR13 - BASIC IGNITION TIMING . If pattern is not correct, repair secondary ignition system.

WARM DR13 - BASIC IGNITION TIMING

Connect tachometer and power timing light to engine. Disconnect and plug vacuum hose at distributor. Warm engine to normal operating temperature. Check that idle speed is within 700-900 RPM.
Ignition timing should be within 2° of specification shown on emission label. If so, proceed to Warm DR14 below. If timing is not within proper range, adjust as necessary.

WARM DR14 - MECHANICAL ADVANCE

If basic ignition timing was okay, raise engine speed to 3800 RPM. Timing should be 11-19 BTDC (preferably 15° BTDC) at 2800 RPM on vehicles with distributor No. MD067134; 15-23° BTDC (preferably 19° BTDC) at 2800 RPM on vehicles with distributor No. XD094020. If not within specified range, remove distributor. Check mechanical advance weights and springs. Repair as necessary. If okay, go to WARM DR15 - VACUUM ADVANCE test below.

WARM DR15 - VACUUM ADVANCE

Return engine to idle speed. Connect an auxiliary vacuum supply to distributor and apply 12 in. Hg vacuum. Timing should be 33-41° BTDC for all vehicles.
If timing is not to specifications, replace vacuum advance diaphragm. If timing is okay, proceed to «WARM DR16 - ENGINE IDLE RPM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr16-engine-idle-rpm) below.

WARM DR16 - ENGINE IDLE RPM

Turn off all lights and accessories. Connect a tachometer to engine. Disconnect radiator cooling fan, and warm engine to normal operating temperature. Turn engine off. Disconnect the battery negative cable for 3 seconds and then reconnect it. Disconnect the oxygen sensor connector, and restart the engine.
Increase engine speed to 2500 RPM for 10 seconds and permit it to return to idle speed. Wait 2 minutes for engine speed to stabilize. Idle speed should be 700-900 RPM. If idle speed is okay, proceed to «WARM DR17 - PROPANE RPM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr17-propane-rpm) below.
If idle speed is not okay, turn idle speed screw until correct RPM is achieved.

WARM DR17 - PROPANE RPM

Turn off all lights and accessories. Connect a tachometer to engine. Disconnect radiator cooling fan, and warm engine to normal operating temperature. Turn engine off. Disconnect the battery negative cable for 3 seconds and then reconnect it. Disconnect the oxygen sensor connector, and restart the engine.
Run engine for more than 2 minutes. Remove fresh air duct from air cleaner. Insert propane hose 4 inches into the air cleaner snorkel. Open propane main valve. Meter propane until maximum RPM is reached.
Engine speed should increase by 40-90 RPM. If such increase occurs, proceed to «WARM DR18 - OXYGEN FEEDBACK SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis) below. If engine speed increase is not within proper range, adjust by proper propane assisted idle set procedures.

Scheme 91

Scheme 91: WARM DR18 - OXYGEN FEEDBACK SYSTEM

Scheme 92

Scheme 93

Connect voltmeter negative lead to ground. Connect positive lead to cavity No. 1 of 7-wire ECU connector. Warm engine to normal operating temperature. Increase engine speed to 2000 RPM for 30 seconds and then let speed return to idle speed. (Scheme 91): 7-Wire ECU Connector
If voltmeter gives variable readings of 3-11 volts, proceed to «WARM DR19 - ENRICHMENT VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage is steady at 0-1 volt or has variable readings of 0-3 volts, proceed to step 3). If voltage is within 1 volt of battery voltage, proceed to step 7). If voltage is steady between 3-11 volts, proceed to step 10).
With engine running for at least 1 minute at operating temperature and voltmeter positive lead attached to cavity No. 1 of 7-wire ECU connector, remove air intake housing from carburetor. Close choke blade. If voltmeter shows an increase in voltage, check engine for vacuum leaks. If no leaks are found, repair carburetor.
If in step 3) voltage did not increase, disconnect 7-wire ECU connector. If voltage is now within 1 volt of battery voltage, replace ECU. If voltage is still 0-3 volts, turn ignition switch off.
Disconnect 6-wire carburetor connector. Connect ohmmeter leads to Dark Blue and Red/White jet mixture valve wires. If ohmmeter does not show some continuity, replace jet mixture solenoid. (Scheme 92): Carburetor 6-Wire Connector
If some continuity was indicated in step 5), connect voltmeter negative lead to ground. Attach positive lead to Blue wire of harness end of 6-wire carburetor connector. Turn ignition switch to the "RUN" position. Voltmeter should read within 1 volt of battery voltage. If voltage is correct, repair open or shorted wire of cavity No. 1 of 7-wire ECU connector. If voltage is incorrect, repair open wire to ignition switch. (Scheme 93): Carburetor 6-Wire Harness Connector
If voltage was within 1 volt of battery voltage in step 2), run engine for at least 1 minute at operating temperature. Connect negative lead of voltmeter to ground and positive lead to cavity No. 1 of 7-wire ECU connector. Remove PCV hose from valve cover and place your finger over it. If engine stalls before you can put your finger over hose, restart and wait 1 minute before performing test. Slowly move your finger, allowing air to enter hose.
Voltmeter should indicate a decrease in voltage. If voltage decreases, check for gas in crankcase, and service as necessary. If no gas is found, repair carburetor.
If voltage did not decrease in step 8), replace ECU, if wire between ignition coil negative terminal and cavity 10 of 13-wire ECU connector does not have an open circuit.
If voltage was steady between 3-11 volts in step 2), run engine for at least 1 minute at operating temperature. Connect voltmeter negative lead to ground. Attach positive lead to cavity No. 1 of 7-wire ECU connector. Increase engine speed to 2000 RPM for 30 seconds.
Voltmeter should provide variable readings of 3-11 volts. If voltage is okay, proceed to «WARM DR19 - ENRICHMENT VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis). If voltage is still steady, replace oxygen sensor.

Scheme 94

Scheme 94: WARM DR19 - ENRICHMENT VALVE

Scheme 95

Scheme 96

Connect voltmeter negative lead to a good ground. Connect positive lead to cavity No. 5 of 7-wire ECU connector. Start engine and let speed stabilize for 30 seconds. Voltmeter should read within 1 volt of battery voltage. If voltage is 0-1 volt, proceed to step 3). (Scheme 94): 7-Wire ECU Connector
If voltage was correct in step 1), very rapidly increase engine speed to 4000 RPM and let it return to idle. Speed increase must be RAPID. Voltmeter should momentarily drop from battery voltage to 0-1 volt. If it does, proceed to «WARM DR20 - BOWL VENT VALVE»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr20-bowl-vent-valve). If voltage did not drop in step 2), replace ECU if wire from ignition coil negative terminal to cavity No. 10 of 13-wire ECU connector has no open circuit.
If 0-1 volt reading was indicated in step 1), turn ignition switch off. Disconnect 6-wire carburetor connector. Connect ohmmeter leads to Yellow/Orange and Red enrichment valve wires of carburetor connector. If no continuity is indicated, replace enrichment valve.. (Scheme 95): Carburetor 6-Wire Connector
If some continuity exists, disconnect 6-wire carburetor connector. Connect voltmeter negative lead to a good ground. Connect positive lead to Blue wire of carburetor harness connector. Turn ignition switch to "RUN" switch. Voltmeter should read within 1 volt of battery voltage. (Scheme 96): Carburetor 6-Wire Harness Connector
If 0 volts are indicated, repair open in Blue wire leading to ignition switch. If voltage is okay, repair open or shorted wire of cavity No. 5 of 7-wire ECU connector.

WARM DR20 - BOWL VENT VALVE

Remove bowl vent hose from carburetor and canister. Blow lightly into hose. If air does not pass through hose, clear hose or replace external bowl vent valve.
If air passes through hose, start engine and blow lightly into hose. Air should not pass through hose. If air passes through hose, check electrical circuit to bowl vent valve. If okay, replace bowl vent valve. If air did not pass through hose, go to «WARM DR21 - HEATED AIR SYSTEM»(/dodge/aries/i-1981-1989/remont/testing-diagnostics/#26l-carburetor-cec-diagnosis__warm-dr21-heated-air-system) test below.

Canisters. Scheme 97

Scheme 97: Canisters

WARM DR21 - HEATED AIR SYSTEM

Remove outside air duct from air cleaner. Start engine. The heat door should be in the heat off position with air intake temperature higher than 113°F.
If heat door is in proper position, all engine control systems are working properly. If problem still exists, check vacuum, valve timing and compression. Check engine cooling, exhaust and PCV systems. Check fuel pump pressure, volume, and vacuum. Check torque converter stall speed and power brake booster. Check fuel for contamination and carburetor for proper operation.
If heat door was not in proper position, remove air intake housing. Remove vacuum source hose from temperature sensor. Connect auxiliary source of vacuum and apply 10 in. Hg. Vacuum should not hold. If vacuum holds, replace temperature sensor. If vacuum does not hold, check for sticking heat door.

Heat Door. Scheme 98

Scheme 98: Heat Door

2.6l Carburetor Cec Diagnosis Dodge Aries I