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.
1990 Nissan-Datsun Sentra BaseFACTORY OEM SERVICE PROCEDURE
Engine Compression
- Start engine and warm to normal operating temperature. Release fuel pressure by removing fuel pump fuse. Leave fuse out during compression check. Restart engine. After engine stalls, crank engine 2-3 times to completely release fuel pressure.
- Disconnect distributor center cable. Check compression pressure with all spark plugs removed, throttle valve wide open and engine at specified cranking speed.
- Crank engine at least 6 revolutions to determine engine compression. Compression reading should be within specification. See ENGINE COMPRESSION table. After servicing engine, turn ignition off and reconnect components disconnected. Erase memory Code 22 (if necessary).
ENGINE COMPRESSION
| Model | Standard psi (kg/cm2 ) | Minimum psi (kg/cm2 ) | Minimum RPM |
|---|---|---|---|
| Pulsar NX & Sentra | 181 (12.7) | 142 (10.0) | 350 |
Factory Service Tools
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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.