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 MANUALSCHEVROLET1990S10/T10 BLAZER 2WD V6-173 2.8LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMIGNITION TIMINGADJUSTMENTS
1990 Chevrolet S10/T10 Blazer 2WD V6-173 2.8L
Ignition Timing: Adjustments
1990 Chevrolet S10/T10 Blazer 2WD V6-173 2.8LSECTION 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 the SET TIMING connector (tan/black wire), taped to the harness below the heater case in the passenger compartment. DO NOT disconnect 4 wire connector at distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor.
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.
Timing Connector-In Pass Comp Behind Carpet, Below Heater:
PROCEDURE:
Set timing under the following conditions:
^ Normal operating temperature.
^ Air cleaner installed.
^ A/C "OFF".
^ Transmission in neutral.
^ Disconnect the SET TIMING connector (tan/black wire), taped to the harness below the heater case in the passenger compartment. DO NOT disconnect 4 wire connector at distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor.
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.