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 MANUALSCHEVROLET1990LUMINA APV V6-191 3.1LREPAIR AND DIAGNOSISENGINE, COOLING AND EXHAUSTENGINETUNE-UP AND ENGINE PERFORMANCE CHECKSIGNITION TIMINGADJUSTMENTS
1990 Chevrolet Lumina APV V6-191 3.1L
Ignition Timing: Adjustments
1990 Chevrolet Lumina APV V6-191 3.1LSECTION 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
Timing must be checked under the following conditions:
- Normal operating temperature.
- Air cleaner installed.
- A/C "OFF".
- Transmission in Neutral or Park.
Timing Check:
- Ground the SET TIMING connector, a single tan wire with a black stripe that breaks out from the engine harness located adjacent to the RH shock tower. DO NOT disconnect 4 wire connector at distributor.
- Connect timing light and adjust as necessary to 10° (BTDC) by loosening hold down bolt and rotating distributor.
- Tighten hold down to 34 Nm (25 lb ft) and recheck the timing.
- Stop the engine and remove ground from SET TIMING connector.
Typical Timing Mark:
PROCEDURE
Timing must be checked under the following conditions:
- Normal operating temperature.
- Air cleaner installed.
- A/C "OFF".
- Transmission in Neutral or Park.
Timing Check:
- Ground the SET TIMING connector, a single tan wire with a black stripe that breaks out from the engine harness located adjacent to the RH shock tower. DO NOT disconnect 4 wire connector at distributor.
- Connect timing light and adjust as necessary to 10° (BTDC) by loosening hold down bolt and rotating distributor.
- Tighten hold down to 34 Nm (25 lb ft) and recheck the timing.
- Stop the engine and remove ground from SET TIMING connector.
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.