Jeep 1987 Wrangler Workshop Manual page 1156

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
s p e c i f i c a t i o n s , and the V e h i c l e
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 E F 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
s p e c i f i c a t i o n s , and the V e h i c l e
Emission Control Information Update
label removed.
On 1986 Eagle/Jeep, 49-State/California/
C a n a d a 4 . 2 L m o d e l s , with a u t o m a t i c
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 ex-
pose 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 E F 8980 000 819, next to
the original label.
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