Citation V6-173 2.8L VIN Z 2-bbl HP (1983)
Ignition Control Module: All Technical Service Bulletins
Engine - Roughness
Number:
83-T-3
Section:
VIy
Date:
Nov., 1982
Subject:
ENGINE ROUGHNESS - 1983 "A" OR "X" CARS WITH 2.8L V6 ENGINES RPO LE2 OR LH7
TO:
ALL CHEVROLET DEALERS
Some early production 1983 "A" or "X" cars with 2.8L LE2 or LH7 engines may exhibit an engine roughness which can be caused by stray
electronic signals received by the distributor module which produce a false (high RPM) tach reference pulse to ECM. The roughness is
most evident at idle but may persist during acceleration and at driving speeds.
Roughness caused by the false reference pulse can be alleviated by re-orienting the distributor module and re-routing the lead wires as
follows:
1.
Disconnect primary coil leads at the coil.
2.
Disconnect the ECM four (4) wire connector.
3.
Remove the ignition wires and coil wire from the distributor cap.
4.
Remove the distributor cap.
5.
Cut a 230 mm (9 inch) length of .350 I.D. conduit (P/N 8919354) and install on the distributor primary leads. Cut an 85 mm (3.3
inch) length of the above conduit and install on the four (4) wire ECM leads at the distributor.
6.
Crank the engine until the white timing mark on the torsional damper and the "O" on the timing indicator are in alignment and the
distributor rotor is in the #1 spark position.
7.
Remove the distributor clamp screw and hold down clamp.
8.
a. Slowly raise the distributor until the rotor just stops turning counter clockwise.
b.
Rotate the distributor base and rotor simultaneously in a clockwise direction until the lead wires are in a 7 o'clock position when
viewed along the centerline of the engine from the rear face of the engine. Be sure the distributor is rotated enough so that the
lead wires clear the coil bracket hold down bolt.
9.
Reinstall the distributor and hold down clamp and clamp screw (loose).
10.
Reinstall the distributor cap.
11.
Reinstall the ignition wires and coil wire in their original terminal posts. In those applications where #3 ignition wire proves to be
too short, substitute ignition wire, P/N 12036948 (24 inches long).
12.
Route the primary coil lead under the right side (wires 1, 3, 5) ignition wires and attach to the coil.
13.
Set the timing to specifications on the tune up label and tighten the hold down clamp screw.
14.
Reconnect the ECM four (4) wire connector.
Labor Operation Number:
T0115
Labor Time
:
.3 hours
