Engine - Detonation (Spark Knock)

Number 83-T-82A Section 6 Date 6/85

Subject: DETONATION (SPARK KNOCK)

1983 2000 MODELS EQUIPPED WITH 2.0L ENGINE (VIN CODE P)

This cancels and supersedes information contained in Pontiac Dealer Service Bulletin 83-T-82. This copy identifies an additional PROM application.

This bulletin should be used when detonation (spark knock) is encountered on some 1983 2000 models. It should be noted that "burst" detonation (very short periods following a quick throttle movement) is considered acceptable.

1. Check base timing 0~ (by-pass disconnected).

2. Check for proper EGR per chart (see Page 2).

3. If timing and EGR system checks are satisfactory.

A. On manual transmission vehicles:

^ Retard base timing to 4~ ATDC.
^ Install tune-up label, P/N 14086563.

B. On automatic transmission vehicles:

^ Install PROM package:

- With Federal emissions and without Cold Startability Revision (reference Pontiac Dealer Service Bulletin 84-6 (Gasoline)-87), P/N 1226823.

- With Federal emissions and with Cold
Startability Revision (reference Pontiac Dealer Service Bulletin 84-6 (Gasoline)-87), P/N 1227253.

- With California emissions, P/N 1226984.

^ Set base timing to 6~ BTDC.

^ Install tune-up label that is included in PROM package.
Use applicable labor operation.

CHART 8:

1983 CHART 8 FUEL INJECTION EGR CHECK 2.0L AND 5.0L