Riviera V6-231 3.8L Turbo VIN 3 4-bbl (1982)
^
Proper operation of EGR valve.
^
Correct EGR valve application for engine.
^
Plugged EGR passages in the cylinder head or intake manifold.
EGR system diagnosis can be found on Page 6E-63 and EGR valve check on Page 6E-49 of the 1982 Chassis Service Manual.
2.
Plugged, or pinched or leaking vacuum hoses.
3.
Proper operation of Early Fuel Evaporation (EFE) Valve.
4.
Restricted fuel system, i.e.; plugged fuel filter, etc.
ADDITIONAL CAUSES OF DETONATION
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Low back pressure (removed catalytic converter or beads).
^
Stuck thermal.
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Lean carburetor (secondaries stuck closed), stuck metering rods.
^
TCC engagement too low (TPS not set to specs).
Technical Service Bulletin # 82T4460
Date: 820301
Engine - Light Spark Knock While Accelerating
Model Year
1982
Bulletin No.
82-T-44
File in Group 60
Number
23
Date
Mar., 82
SUBJECT:
Spark Knock
MODELS AFFECTED:
1981-82 3.8L, V-6
An occasional light spark knock while accelerating or driving up hills should be no cause for concern. Under this mode, light spark knock indicates that
the greatest fuel economy is being achieved.
Two other conditions where the engine might spark knock, but would be considered normal are:
A.
At idle with a quick throttle opening; 2 or 3 cylinders may knock until the ECM re-adjusts timing.
B.
During medium throttle opening, when throttle is rapidly closed; 2 or 3 cylinders may knock until the ECM re-adjusts timing.
Engine spark knock, other than described above, is abnormal and can be corrected. Normally, three things cause an engine to spark knock.
1.
Fuel octane rating below requirements.
2.
Incorrect ignition timing.
3.
Lean fuel mixture; incorrect EGR operation.
Although it is not common, an abnormally high compression ratio can cause the engine to spark knock at wide open throttle. This spark knock may also
be heard under light throttle. Spark knock under these conditions is generally caused by excessive carbon build-up on the piston or cylinder head. A can
