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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1984VALUE VAN P2500, 5.7 M, STANDARD, SM465/M20REPAIR AND DIAGNOSISENGINE PERFORMANCEADJUSTMENTTUNE-UP - 5.7L V8 VIN [M]IGNITION SYSTEMIGNITION TIMING
1984 GMC Value Van P2500, 5.7 M, Standard, SM465/M20
Ignition Timing
1984 GMC Value Van P2500, 5.7 M, Standard, SM465/M20SECTION Ignition Timing
NOTE:
Engines are equipped with a receptacle for magnetic probe timing lights, located 10° ATDC. DO NOT
use this location for timing with a conventional light.
- Connect an adapter between No. 1 spark plug wire or use an inductive type pickup. DO NOT puncture wires. Connect timing light according to manufacturer's instructions.
- Check or adjust ignition timing with engine at normal operating temperature, distributor vacuum line disconnected and plugged. See Figure . Put transmission in neutral.
- Once timing has been set, reconnect the vacuum line.
TIMING SPECIFICATIONS (Degrees BTDC @ RPM)
| Application | Man. Trans. | Auto. Trans | |
|---|---|---|---|
| 5.7L Heavy Duty | |||
| Federal | 4 @ 700 | 4 @ 700 | |
| Calif. | 6 @ 700 | 6 @ 700 | |
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.