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 MANUALSCHEVROLET1989SUBURBAN 1/2 TON 2WD V8-454 7.4LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMIGNITION TIMINGADJUSTMENTS
1989 Chevrolet Suburban 1/2 Ton 2WD V8-454 7.4L
Ignition Timing: Adjustments
1989 Chevrolet Suburban 1/2 Ton 2WD V8-454 7.4LSECTION Adjustments
NOTE: Timing specifications are listed on the Vehicle Emissions Control Information label under the hood. Always follow the Vehicle Emissions Control Information label procedures first before using the following procedure.
PROCEDURE:
Set timing under the following conditions:
^ Normal operating temperature.
^ Air cleaner installed.
^ A/C "OFF".
^ Transmission in neutral.
^ Disconnect SET TIMING connector (tan/black wire) located in harness close to distributor. DO NOT disconnect 4 wire connector at distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor. For specification, refer to SPECIFICATIONS/ELECTRICAL AND ELECTRONIC SPECIFICATIONS/TIMING SPECIFICATIONS. Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear ECM trouble code by disconnecting ECM power source.
NOTE: Dual timing scribes are on the 4.3L engine balancers. They line up with the timing indicators at one o'clock and four o'clock positions. Use the one o'clock position.
PROCEDURE:
Set timing under the following conditions:
^ Normal operating temperature.
^ Air cleaner installed.
^ A/C "OFF".
^ Transmission in neutral.
^ Disconnect SET TIMING connector (tan/black wire) located in harness close to distributor. DO NOT disconnect 4 wire connector at distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor. For specification, refer to SPECIFICATIONS/ELECTRICAL AND ELECTRONIC SPECIFICATIONS/TIMING SPECIFICATIONS. Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear ECM trouble code by disconnecting ECM power source.
NOTE: Dual timing scribes are on the 4.3L engine balancers. They line up with the timing indicators at one o'clock and four o'clock positions. Use the one o'clock position.
RENDER: 1.0x
NO RELATED
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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.