Engine - Altitude Performance Adjustment
85AMC/jeep03OCTOBER 1985 000 816
1986 AMC/JEEP/RENAULT MODELS
35E
ENGINES Attention: Workshop, Parts Department
ALTITUDE PERFORMANCE ADJUSTMENTS
This I.S. Note outlines adjustment for optimum engine performance on 1986 AMC/Jeep/Renault models being operated at high or low altitudes.
When necessary, perform the engine adjustments outlined in this I.S. Note. In addition, any 1986 model that is so adjusted must have a unique Emission Control Information Update label installed. The part numbers for these unique labels are provided in the adjustment procedures outlined in this I.S. Note.
The adjustment procedures and unique labels must be made available at no cost to independent repair facilities and the general public. A notification is also provided in current owner manuals to make the owner aware of these adjustments. The Emission Control Information Update labels and technical information are available from:
Myriad 8835 General Drive Plymouth, MI 48170 1-800-AMC-CARS Operator 43
CONTENTS
1. 1986 Alliance/Encore 1.4L - 1.7L Engines and Sportwagon 2.2L Engines
2. 1986 Cherokee/Wagoneer/Comanche 2.8L Engines, 2.46L Engines With Throttle Body Injection and 2.1L Turbo-Diesel Engines
3. 1986 CJ 2.46L Carburetor Equipped Engines
4. 1986 Eagle/CJ/Grand Wagoneer/Truck 4.2L Engines
5. 1986 Grand Wagoneer/Truck 5.9L Engines
FILING INSTRUCTIONS
Record this I.S. Note on the index page of Chapter B, Engines, in the appropriate M.R. manual.
1. 1986 ALLIANCE/ENCORE 1.4L-1.7L ENGINES AND SPORTWAGON 2.2L ENGINES
1986 Alliance/Encore 1.4L - 1.7L engines and Sportwagon 2.2L engines do not require adjustment. The electronic control systems on these engines have built-in compensating circuits that make necessary adjustments automatically.
2. 1986 CHEROKEE/WAGONEER/COMANCHE 2.8L ENGINES, 2.46L ENGINES WITH THROTTLE BODY INJECTION AND 2.1L TURBO-DIESEL ENGINES
For 1986, only the Cherokee/Wagoneer/ Comanche, 49-State and Canada 2.8L gasoline engine requires adjustment as outlined below. The 1986 49-State and Canada 2.1L TurboDiesel engine, 1986 California 2.8L gasoline engine, and 1986 49-State and California 2.4 engine with throttle body injection do not require adjustment. The fuel metering control systems on these engines have built-in compensating devices that make necessary adjustments automatically. The 2.8L engine adjustments are as follows.
Adjustment - 49-State and Canada 2.8L Engines
On 1986, 49-State and Canada Cherokee/ Wagoneer/Comanche 2.8L models sold for operation at altitudes below 4,000 feet that are being operated above 4,000 feet, the ignition timing as shown on the original Vehicle Emission Control Information label in the engine compartment, should be advanced 7~ and engine idle speed reset to the specifications indicated on this same label.
1. Advance ignition timing 7~ from the setting indicated on the original Vehicle Emission Control Information label and reset engine idle speed to the setting indicated on the same label.
2. Install Vehicle Emission Control Information Update label, part number EF 8980 000 818, next to the original label.
This adjustment applies to 1986 Cherokee/ Wagoneer/Comanche, 49-State and Canada 2.8L models that were originally sold for principal use at altitudes below 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes below 4,000 feet, the ignition timing and engine idle speed must be reset to original specifications and the Vehicle Emission Control Information Update label removed.
On 49-State and Canada 1986 Cherokee/ Wagoneer/Comanche 2.8L models sold for operation at altitudes above 4,000 feet that are being operated below 4,000 feet, the ignition timing as shown on the original Vehicle Emission Control Information label in the engine compartment should be retarded 7~ and engine idle reset to the specification indicated on this same label.
1. Retard ignition timing 7~ from the setting indicated on the original Vehicle Emission Control label and reset engine idle speed to the setting indicated on this same label.
2. Install Vehicle Emission Control Information Update label, part number EF 8980 000 819, next to the original label.
This adjustment applies to 1986 Cherokee/ Wagoneer/Comanche, 49-State and Canada 2.8L models that were originally sold for principal use at altitudes above 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes above 4,000 feet, the ignition timing and engine idle speed must be reset to original specifications and the Vehicle Emission Control Information Update label removed.
3. 1986 CJ 2.46L CARBURETOR EQUIPPED ENGINES
1986, 2.46L carburetor equipped engines in California/49-State/Canada CJ models require adjustment as outlined below.
Adjustment - California/49-State/Canada Carburetor Equipped 2.46L Engines
On 1986 California/49-State/Canada models, with a carburetor equipped 2.46L engine, originally sold for operation at altitudes below 4,000 feet that are being operated above 4,000 feet, the ignition timing as shown on the original Vehicle Emission Control Information label in the engine compartment, should be advanced 7~ and engine idle speed reset to the specifications indicated on this same label. In addition, a ground wire must be connected to the MCU circuit to activate the altitude compensating circuit in the MCU.
1. Locate the black with tracer altitude circuit ground wire. The wire is in the MCU harness. It is located near the ignition coil, or at the rear-center of the engine compartment between the dash panel and air cleaner.
2. Remove the tape from the eyelet attached to the end of the ground wire.
3. Connect the ground wire eyelet to a convenient ground location on the engine.
4. Advance ignition timing 7~ from the setting indicated on the original Vehicle Emission Control Information label and reset engine idle speed to the setting indicated on the same label.
5. Install Vehicle Emission Control Information Update label, part number EF 8980 000 818, next to the original label.
This adjustment applies to 1986 CJ California/ 49-State/Canada models, with a carburetor equipped 2.46L engine, originally sold for principal use at altitudes below 4,000 feet. Refer
to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes below 4,000 feet, the MCU circuit jumper wire must be removed, the ignition timing and engine idle speed reset to original specifications and the Vehicle Emission Control Information Update label removed.
On 1986, California/49-State/Canada CJ models with a 2.46L carburetor equipped engine, originally sold for use at altitudes above 4,000 feet that are being operated below 4,000 feet, the ignition timing, as shown on the original Vehicle Emission Control Information label in the engine compartment should be retarded 7~ and engine idle reset to the specification indicated on this label. In addition, the MCU circuit ground wire must be disconnected and taped to the MCU harness.
1. Disconnect the black with tracer altitude circuit ground wire from the engine.
2. Cover the connector eyelet with tape and secure the wire to the MCU harness with tape or a tie strap.
3. Retard ignition timing 7~ from the setting indicated on the original Vehicle Emission Control label and reset engine idle speed to the setting indicated on this same label.
4. Install Vehicle Emission Control Information Update label, part number EF 8980 000 819, next to the original label.
This adjustment applies to the 1986 California/ 49-State/Canada CJ models, with a carburetor equipped 2.46L engine, that were originally sold for principal use at altitudes above 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes above 4,000 feet, the MCU circuit jumper wire must be reconnected, the ignition timing and engine idle speed reset to original specifications, and the Vehicle Emission Control Information Update label removed.
4. 1986 EAGLE/CJ/GRAND WAGONEER/TRUCK 4.2L ENGINES
1986 Eagle/Jeep 49-State and California/ Canada 4.2L engines require adjustment. However, the adjustment procedures for models with automatic or manual transmission are different. Refer to the following procedures.
Adjustment - 49-State/California/Canada 4.2L Models With Automatic Transmission
1986 Eagle/Jeep, 49-State/California/Canada 4.2L models with automatic transmission, originally sold for operation at altitudes below 4,000 feet that are being operated above 4,000 feet, the ignition timing must be advanced 7~ and engine idle speed reset. In addition, a jumper wire must be added to the MCU circuit to activate the altitude compensating circuit in the MCU.
1. On Eagle models, move the carpeting away from the passenger side toeboard to expose the MCU harness. Untape the two-terminal connector from the harness. Connect jumper wire, 318 6890, to the two-terminal connector and reinstall the carpet.
2. On Jeep models, locate the black with tracer altitude circuit ground wire. The wire is in the MCU harness located near the ignition coil. Remove the tape covering the eyelet on the ground wire and attach the eyelet to the engine ground screw near the ignition coil.
3. Advance ignition timing 7~ from the setting indicated on the original Vehicle Emission Control Information label in the engine compartment and reset the engine idle speed to the setting indicated on the same label.
4. Install Vehicle Emission Control Information Update label, part number EF 8980 000 818, next to the original label.
These adjustments apply to 1986 Eagle/Jeep, 49-State/California/Canada 4.2L models with automatic transmission, originally sold for principal use at altitudes below 4,000 feet. Refer to the Vehicle Emission Control Information label to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes below 4,000 feet, the MCU circuit jumper wire must be removed, the ignition timing and engine idle speed reset to original specifications, and the Vehicle Emission Control Information Update label removed.
On 1986 Eagle/Jeep, 49-State/California/ Canada 4.2L models, with automatic transmission originally sold for operation at altitudes above 4,000 feet that are being operated below 4,000 feet, the ignition timing should be retarded 7~ and engine idle reset. In addition, the MCU circuit jumper wire must be disconnected and taped to the MCU harness.
1. On Eagle models, move the carpeting away from the passenger side front toeboard to expose the MCU harness. Disconnect the jumper wire from the two-terminal connector in the MCU harness and tape the connector securely to the harness. Then place the jumper wire in the glove box.
2. On Jeep models, disconnect the black with tracer altitude circuit ground wire from the engine. Cover the ground wire eyelet with tape and secure the wire to the MCU harness with tape or a tie strap.
3. Retard ignition timing 7~ from the setting indicated on the original Vehicle Emission Control label in the engine compartment and reset engine idle speed to the setting indicated on this same label.
4. Install Vehicle Control Information Update label, part number EF 8980 000 819, next to the original label.
These adjustments apply to 1986 Eagle/Jeep, 49-State/California/Canada 4.2L models, with automatic transmission, originally sold for principal use at altitudes above 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes above 4,000 feet, the MCU circuit jumper wire must be reconnected, the ignition timing and engine idle speed reset to original specifications, and the Vehicle Emission Control Information Update label removed.
Adjustment - 49-State/California/Canada 4.2L Models With Manual Transmission
On 1986 Eagle/Jeep, 49-State/California/ Canada 4.2L models with manual transmission, originally sold for operation at altitudes below 4,000 feet that are being operated above 4,000 feet, the ignition timing must be advanced 7~, engine idle speed reset, and a ground wire connected to the MCU circuit. In addition, the idle/decel switch must be connected to the carburetor EGR port instead of the spark port.
1. On Eagle models, move the carpeting away from the passenger side toeboard to expose the MCU harness. Untape the two-terminal connector from the harness. Connect jumper wire, 318 6890, to the two-terminal connector and reinstall the carpet.
2. On Jeep models, locate the black with tracer altitude circuit ground wire. The wire is in the MCU harness located near the ignition coil. Remove the tape covering the eyelet on the ground wire and attach the eyelet to the engine ground screw near the ignition coil.
Fig. 1 Modifying Low Altitude Model for High Altitude Operation:
3. Connect the idle/decel switch to the carburetor EGR port as follows (Fig. 1).
a. Disconnect vacuum line 1 from idle/decel switch and from tee connector 2 (Fig. 1). Place this line in the glove box - do not discard it.
b. Install cap, 813 2325, over the open end of tee connector 2.
c. Cut and install tee connector, 321 0891, in vacuum line 3 (Fig. 1). Position the connector about 1-1/4 inches from the EGRCTO end of the line.
d. Connect 75-inch long vacuum line 4 to the idle/decel switch and to the tee connector in line 3 (Fig. 1).
4. Advance ignition timing 7~ from the setting indicated on the original Vehicle Emission Control Information label in the engine compartment and reset engine idle speed to the setting indicated on the same label.
5. Install Vehicle Emission Control Information Update label, EF 8980 000 818, next to the original label.
These adjustments apply to 1986 Eagle/Jeep, 49-State/California/Canada 4.2L models with manual transmission, originally sold for use at altitudes below 4,000 feet. Refer to the original Vehicle Emission Control Information label to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes below 4,000 feet, the MCU ground wire must be removed, the idle/decel switch reconnected to the carburetor spark port, the ignition timing and idle speed reset to original specifications, and the Vehicle Emission Control Update label removed.
Fig. 1 Modifying Low Altitude Model for High Altitude Operation:
Figure 1 Modifying Low Altitude Model for High Altitude Operation
1. IDLE/DECEL SWITCH-TO-SPARK PORT VACUUM LINE (REMOVE AND PLACE IN GLOVEBOX).
2. SPARK PORT VACUUM LINE TEE CONNECTOR (USE CAP 8132325 TO PLUG CONNECTOR AFTER REMOVING LINE 1).
3. EGR PORT-TO-EGR-CTO VACUUM LINE (INSTALL TEE CONNECTOR 3210891 IN THIS LINE ABOUT 1-1/4 INCHES FROM EGR-CTO END OF LINE).
4. 75 INCH LINE, 1/8 INSIDE DIAMETER VACUUM LINE USED TO RECONNECT IDLE/DECEL SWITCH TO EGR PORT 5 (VIA TEE CONNECTOR IN LINE 3).
5. CARBURETOR EGR PORT (E).
6. CARBURETOR SPARK PORT(S).
On 1986 Eagle/Jeep, 49-State/California/ Canada 4.2L models with manual transmission originally sold for operation at altitudes above 4,000 feet that are being operated below 4,000 feet, the ignition timing must be retarded 7~, engine idle speed reset and the MCU ground wire removed. In addition, the idle/decel switch must be connected to the carburetor spark port instead of the EGR port.
1. On Eagle models, move the carpeting away from the passenger side front toeboard to expose the MCU harness. Disconnect the jumper wire from the two-terminal connector in the MCU harness and tape the connector securely to the harness. Then place the jumper wire in the glove box.
2. On Jeep models, disconnect the black with tracer altitude circuit ground wire from the engine. Cover the ground wire eyelet with tape and secure the wire to the MCU harness with tape or a tie strap.
Fig. 2 - Modifying High Altitude Model for Low Altitude Operation:
3. Connect the idle/decel switch to the carburetor spark port as follows (Fig. 2).
a. Cut and install tee connector, 321 0891, in vacuum line 1 (Fig. 2). Position the connector about 1-1/4 inches from the spark port end of the line.
b. Disconnect vacuum line line 2 from tee connector 3. Then reconnect line 2 to the tee connector just installed in vacuum line 1 (Fig. 2).
c. Plug open end of tee connector 3 with cap 813 2325.
4. Retard ignition timing 7~ from the setting specified on the original Vehicle Emission Control Information label and reset idle speed to the setting on the same label.
5. Install Vehicle Emission Control Information Update label, EF 8980 000 819, next to the original label.
These adjustments apply to 1986 AMC/Jeep, 49-State/California/Canada 4.2L models with manual transmission originally sold for use at
altitudes above 4,000 feet. Refer to the original Vehicle Emission Control Information label to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes above 4,000 feet, the MCU ground wire must be reinstalled, the idle/decel switch reconnected to the EGR port, the ignition timing and idle speed reset and the Vehicle Emission Control Information Update label removed.
5. 1986 GRAND WAGONEER/TRUCK 5.9L ENGINES
On 1986 Grand Wagoneer/Truck, 49-State/ California/Canada 5.9L models originally sold for operation at altitudes below 4,000 feet that are being operated above 4,000 feet, the ignition timing as shown on the original Vehicle Emission Control Information label in the engine compartment, should be advanced 7~ and engine idle speed reset to the specifications indicated on this same label.
1. Advance ignition timing 7~ from the setting indicated on the original Vehicle Emission Control Information label and reset engine idle speed to the setting indicated on the same label.
2. Install Vehicle Emission Control Information Update label, part number EF 8980 000 818, next to the original label.
These adjustments apply to 1986 Grand Wagoneer/Truck, 49-State/California/Canada 5.9L V-8 models originally sold for principal use at altitudes below 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes below 4,000 feet, the ignition timing and engine idle speed must be reset to original specifications and the Vehicle Emission Control Information Update label removed.
On 1986 Grand Wagoneer/Truck, 49-State/ California/Canada 5.9L models originally sold for operation at altitudes above 4,000 feet that are being operated below 4,000 feet, the ignition timing as shown on the original Vehicle Emission Control Information label in the engine compartment should be retarded 7~ and engine idle reset to the specification indicated on this same label.
1. Retard ignition timing 7~ from the setting indicated on the original Vehicle Emission Control label and reset engine idle speed to the setting indicated on this same label.
2. Install Vehicle Emission Control Information Update label, part number EF 8980 000 819, next to the original label.
These adjustments apply to 1986 Grand Wagoneer/Truck, 49-State/California/Canada 5.9L models originally sold for principal use at altitudes above 4,000 feet. Refer to the Vehicle Emission Control Information label in the engine compartment to identify these vehicles.
NOTE: Whenever these vehicles are returned to operation at altitudes above 4,000 feet, the ignition timing and engine idle speed must be reset to original specifications and the Vehicle Emission Control Information Update label removed.
Fig. 2 - Modifying High Altitude Model for Low Altitude Operation:
Figure 2 - Modifying High Altitude Model for Low Altitude Operation