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PROM - Detonation During Throttle Movement

Bulletin 85-6E-5A

Date Apr. '85

Ref. No. 85-126A-6E
SUBJECT: DETONATION (SPARK KNOCK)

MODELS AFFECTED: 1983 SKYHAWKS EQUIPPED WITH 2.0L ENGINE (VIN CODE P)


NOTICE: This bulletin supersedes Bulletin 85-6E-5 dated Mar. '85. Please discard bulletin 85-6E-5 and replace it with this one, 85-6E-5A..


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

ELECTRONIC FUEL INJECTION 6E2-35:




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

2. Check for proper EGR per chart (Figure 1).

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 - P/N 1226823.
- 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.