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Home >> Eagle >> 1987 >> Eagle Sedan L6-258 4.2L >> Repair and Diagnosis >> Engine, Cooling and Exhaust >> Engine >> Tune-up and Engine Performance Checks >> Ignition Timing >> Technical Service Bulletins >> All Technical Service Bulletins >> Engine - Altitude Performance Adjustments >> Procedure

Procedure




NOTE: These adjustment procedures are written to coincide with the specifications found on the Vehicle Emission Control Information label.
Specified positions on the label are called out on sample labels in these instructions. The positions (1) (2) (3) and (4), list the vehicle specifications that determine the particular adjustment.


The following information can be identified at these positions on the sample label:

Position Information

1 Engine Type

2 EPA Certification

3 Altitude Application

4 Transmission Type


Vehicles With Automatic Transmissions and Built for Operation BELOW 4,000 Feet Now Being Operated ABOVE 4,000 Feet


1. Raise the hood and support with the rod.



2. Check the Vehicle Emission Control Information label (A) located underhood on the passenger side of the dash panel.

3. Locate positions (1) (2) (3) and (4).


4. Verify that the vehicle is equipped as follows:


1. 4.2L Engine (258 cu.in.)

2. 49-State/California/Canada

3. For Operation BELOW 4,000 Feet

4. Automatic Transmission



5. Move the carpeting away from the passenger-side toe board. This will expose the MCU harness (B).

6. Remove the tape connecting the twoterminal connector (C) to the MCU harness.



7. Connect the MCU circuit jumper wire (D), P/N 318 6890, to the two-terminal connector
8. Reinstall the carpeting.


9. Set the ignition timing to 16~ BTDC, 10. Reset the idle speeds to the specifications on the original Vehicle Emission Control Information label.
11. Attach the Vehicle Emission Control Information Update label, P/N EF 8980 010 600. Position the Update label next to the original Vehicle Emission Control Information label.


12. Stow the support rod and close the hood.


NOTE: Whenever this vehicle is returned to operation at altitudes BELOW 4,000 feet, remove the MCU circuit jumper wire, reset the ignition timing and engine idle speeds to the original specifications, and, remove the Vehicle Emission Control Information Update label.


Vehicles With Automatic Transmissions and Built for Operation ABOVE 4,000 Fed Now Being operated BELOW 4,000 Feet

1. Open the hood and support with the rod



2. Check the Vehicle Emission Control Information label (A) located underhood on the passenger side of the dash panel.
3. Locate positions (1) (2) (3) and (4).


4. Verify that the vehicle is equipped as follows:


1. 4.2L Engine (258 cu.in.)

2. 49-State/California/Canada

3. For Operation ABOVE 4,000 Feet

4. Automatic Transmission



5. Move the carpeting away from the passenger-side toe board. This will expose the MCU harness (B), the two-terminal connector (C), and the MCU circuit jumper wire (D).
6. Disconnect the MCU circuit jumper wire (D) from the two-terminal connector


7. Tape the two-terminal connector to the MCU harness.

NOTE: DO NOT DISCARD THE MCU CIRCUIT JUMPER WIRE. Place it in the glove compartment for reinstallation when this vehicle is returned to operation ABOVE 4,000 feet.
8. Reinstall the carpeting.


9. Set the ignition timing to 9~ BTDC.


10. Reset the idle speeds to the settings on the original Vehicle Control Information label.


11. Attach the Vehicle Emission Control Information Update label, P/N EF 8980 010 601. Position the Update label next to the original label.


12. Stow the support rod and close the hood.

NOTE: Whenever this vehicle is returned to operation at altitudes ABOVE 4,000 feet, reconnect the MCU circuit jumper wire, reset the ignition timing and engine idle speeds to the original specifications, and, remove the Vehicle Emission Control Information Update label.
Vehicles With Manual Transmissions and Built for Operation BELOW 4,000 Feet Now Being Operated ABOVE 4,000 Feet)


1. Open the hood and support with the rod.



2. Check the Vehicle Emission Control Information label (A) located underhood on the passenger side of the dash panel.
3. Locate positions (1) (2) (3) and (4).


4. Verify that the vehicle is equipped as follows:


1. 4.2L Engine (258 cu.in.)

2. 49-State/California/Canada

3. For Operation BELOW 4,000 Feet

4. Manual Transmission



5. Move the carpeting away from the passenger-side front toe board. This will expose the MCU harness (B).
6. Remove the tape connecting the twoterminal connector (C) from the MCU harness.



7. Connect the MCU circuit jumper wire (D), P/N 318 6890 to the two-terminal connector.



8. Reinstall the carpeting.


9. Connect the idle decel switch (E) to the EGR CTO switch. (The idle decel switch is located across from the oil filter on the shock tower.)






Proceed as follows:


^ Disconnect vacuum hose (1) from the idle decel switch and from the T-connector (2) which connects the idle decel switch to the carburetor spark port.
NOTE: DO NOT DISCARD THE VACUUM HOSE. Place the vacuum hose in the glove compartment for reinstallation when this vehicle is returned to operation ABOVE 4,000 feet.



^ Install the vacuum cap, P/N 813 2325, over the open end of the T-connector (2).






^ Cut the vacuum line (3) about 31.75 mm (1 1/4 inches) from the EGR CTO switch (5).


^ Install the T-connector, P/N 321 0891, in vacuum hose (3).



^ Connect a 190.5 cm (75 inch) long vacuum hose (4) to the idle decel switch and to the T-connector just installed in hose (3).
10. Set the ignition timing to 16~ BTDC.


11. Reset the idle speeds to the settings specified on the original Vehicle Emission Control Information label.


12. Attach the Vehicle Emission Control Information Update label, P/N EF 8980 010 600. Position the Update label next to the Vehicle Emission Control Information label.


13. Stow the support rod and close the hood.


NOTE: Whenever this vehicle is returned to operation BELOW 4,000 feet, remove the MCU jumper wire, reconnect the idle decel switch hose to the carburetor spark port, reset the ignition timing and idle speeds to the original specifications, and, remove the Vehicle Emission Control Information Update label.
Vehicles With Manual Transmissions and Built for Operation ABOVE 4,000 Feet Now Being Operated BELOW 4,000 Feet)

1. Open the hood and support with the rod.



2. Check the Vehicle Emission Control Information label (A) underhood on the passenger-side of the dash panel.
3. Locate positions (1) (2) (3) and (4).

4. Verify that the vehicle is equipped as follows:

1. 4.2L Engine (258 cu. in.)

2. 49-State/California/Canada

3. For Operation ABOVE 4,000 Feet

4. Manual Transmission



5. Move the carpeting away from the passenger-side front toe board. This will expose the MCU harness (B), the twoterminal connector (C) and the MCU circuit jumper wire (D).
6. Disconnect the MCU circuit jumper wire (D) from the two-terminal connector


7. Tape the two-terminal connector to the MCU harness.


NOTE: DO NOT DISCARD THE MCU CIRCUIT JUMPER WIRE. Place it in the glove compartment for reinstallation when this vehicle is returned to operation ABOVE 4,000 feet.



8. Reinstall the carpeting.


9. Connect the idle decel switch (E) to the carburetor spark port (5). (The idle decel switch is located across from the oil filter on the shock tower.)



Proceed as follows:

^ Cut the vacuum hose (1) about 31.75 mm (1 1/4 inches) from the carburetor spark port.






^ Install the T-connector, P/N 321 0891.


^ Disconnect the vacuum hose (2) from the Tconnector (3).



^ Connect the vacuum hose (2) to the Tconnector just installed in vacuum hose (1).
^ Plug the open end of the T-connector (3) with vacuum cap, P/N 813 2325.


10. Set the ignition timing to 9~ BTDC.


11. Reset the idle speeds to the settings on the original Vehicle Emission Control Information label.


12. Attach the Vehicle Emission Control Information Update label, P/N EF 8980 010 601. Position the Update label next to the Vehicle Emission Control Information label.


13. Stow the support rod and close the hood.


NOTE: Whenever this vehicle is returned to operation ABOVE 4,000 feet, reconnect the MCU jumper wire, reconnect the idle decel switch vacuum hose to the EGR CTO switch, reset the ignition timing and idle speeds to the original specifications; and, remove the Vehicle Emission Control Information Update label.
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