Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHRYSLER1987FIFTH AVENUE 5.2 4REPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMEFC SYSTEMTESTINGCOLD DRIVEABILITY TEST 12 - IGNITION TIMING CHECK
1987 Chrysler Fifth Avenue 5.2 4
Cold DRIVEABILITY Test 12 - Ignition Timing Check
1987 Chrysler Fifth Avenue 5.2 4SECTION Cold DRIVEABILITY Test 12 - Ignition Timing Check
- Connect a tachometer and timing light to the engine. Ground the carburetor switch. Start and run the engine until normal operating temperature is reached. Raise engine speed to more than 1100 RPM. Disconnect and plug vacuum hose to the computer (2-Bbl. models).
- Engine speed should be within specifications when setting timing. Adjust idle speed to 450-650 RPM (2-Bbl. models) or 550-750 RPM (4-Bbl. models). Basic timing should be within 2° of specification shown on vehicle emission label. Adjust timing if not within specifications.
- Remove jumper lead from carburetor ground switch. Disconnect and plug vacuum hose to the computer (4-Bbl. models). Connect a vacuum pump to the computer. Apply 16 in. Hg vacuum. Raise engine speed to 2000 RPM. Timing should be within 4° of specification. See SPARK ADVANCE SPECIFICATIONS chart.SPARK ADVANCE SPECIFICATIONS (1)
Application Computer No. Spark Advance Federal 4289813 46 Calif. 4289913 46 Calif. & Fed. 4289919 38 Calif. & Fed. 4289921 38 (1) Specifications are plus or minus 4°. - If spark advance is not within specifications, replace the computer. If spark advance is okay, return engine to idle. Disconnect vacuum pump from the computer. Connect a vacuum gauge to the computer vacuum supply hose. Gauge should read manifold vacuum. If vacuum reading is not okay, check and repair vacuum supply from carburetor. If vacuum reading is okay, proceed to COLD DRIVEABILITY TEST 13 .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.