Skylark V6-173 2.8L VIN X 2-bbl (1984)
Knock Sensor: Technical Service Bulletins
Engine - Poor Performance/Driveability/Fuel Mileage
Bulletin 84-6E-8
Date
March '84
Ref. No. 83-213-64A
SUBJECT:
1982, 1983 4.1L, 1983-1/2 3.8L & 1984 3.0L, 3.8L, & 4.1L POOR PERFORMANCE, DRIVEABILITY, FUEL MILEAGE
MODELS AFFECTED: 1982, 1983 REGALS, LESABRES, ELECTRAS, 1983-1/2 REGALS & ALL 1984 BUICK V-6 ENGINES EQUIPPED WITH
ESC
If subject condition is encountered on above listed vehicles the warm, driveability work sheet should be completed as well as the CCC circuit diagnostic
check to determine if any codes are present. Any items found in those tests that are out of specifications must be corrected first.
If all functions are within specifications, and no trouble codes are stored, the condition may be a detonation sensor picking up noises from the engine or
transmission which will retard the timing as much as 19 degrees. To determine if it is occuring, the following procedure should be used:
Diagnosis with ALCL Scan Tool, All With ESC Except 1983-1/2 Regal (Single Board ECM) & All 1984 3.0L, 3.8L & 4.1L Buick Engines:
Drive the vehicle at normal city and highway speed with the scan tool in the knock retard mode, and monitor the degrees of retard. "0" degrees of retard
should be seen on the scan tool (with no spark knock). If reading other than "0" is seen an the scan tool (up to 19 degrees) and no spark knock is present,
disconnect the detonation sensor, and road test the vehicle again at the same speeds as before. If no retard is seen on the second test, the detonation
sensor is picking up noise from the engine or transmission.
Diagnosis with ALCL Scan Tool for 1983-1/2 Regal and All 1984 Buick V-6 Engines:
If a 1983-1/2 Regal or 1984 Buick V-6 equipped vehicle exhibits this condition, different readings will be seen on the ALCL scan tool in the knock
retard mode due to Internal ECM data stream changes.
These readings are no longer direct degrees of retard and are best explained as counts. Figures or counts as seen on the scan tool may be any figure
between 0 and 255. If the number on the scan tool stays constant (the same number) then the engine has 0 degrees retard.
