Engine Control - Basic Diagnostic Procedures - Except S40 & V40: Diagnosis Volvo S80 I

VISUAL INSPECTION

Visually inspect all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

MECHANICAL INSPECTION

Check engine mechanical condition using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer manual for specific instructions.

COMPRESSION RATIO SPECIFICATIONS

COMPRESSION TEST

1. Run engine until operating temperature is reached.
2. On turbocharged models, disconnect charge air pipe from over cylinder head. Cover opening.
3. Remove upper timing belt cover. Remove cover from over ignition coils.
4. Mark each ignition coil and remove. Remove spark plugs.
5. Separate engine speed (RPM) sensor electrical connector.
6. Switch ignition ON. Hold throttle at wide open throttle position. Switch ignition to START and crank engine over until compression gauge reads maximum cylinder pressure. Switch ignition OFF. See «CYLINDER COMPRESSION SPECIFICATIONS»(ref-91291-S32005025572003092500000) table for nominal compression levels.
7. Install components when check is complete. Tighten spark plugs to 22 ft. lbs. (30 N.m). Tighten ignition coils to 90 INCH lbs. (10 N.m). Install ignition coil cover and timing belt cover and tighten fasteners to 72 INCH lbs. (8 N.m).
8. Connect turbo charge air pipe if applicable. Clear fault memory using scan tool. Start engine and check for proper function. Check for any DTCs and repair as necessary.

CYLINDER COMPRESSION SPECIFICATIONS

CYLINDER LEAKAGE TEST

1. Run engine until operating temperature is reached.
2. On turbocharged models, disconnect charge air pipe from over cylinder head. Cover opening.
3. Remove upper timing belt cover. Remove cover from over ignition coils.
4. Mark each ignition coil and remove. Remove spark plugs.
5. Set cylinder No. 1 at TDC. Connect leakdown gauge to cylinder No. 1 and pressurize cylinder. If leakdown is excessive, see «CYLINDER LEAKAGE DIAGNOSIS»(ref-91291-S29446074342003092500000) table or possible causes. Repair as necessary and go to next step.
6. Repeat procedure for every cylinder. Repair as necessary and go to next step when all cylinders are checked. NOTE: It may be necessary to install components and run engine before all cylinders are checked because engine may cool during testing causing variations in test results.
7. Install components when check is complete. Tighten spark plugs to 22 ft. lbs. (30 N.m). Tighten ignition coils to 90 INCH lbs. (10 N.m). Install ignition coil cover and camshaft cover and tighten fasteners to 72 INCH lbs. (8 N.m).
8. Connect turbo charge air pipe if applicable. Clear fault memory using scan tool. Start engine and check for proper function. Check for any DTCs and repair as necessary.

CYLINDER LEAKAGE DIAGNOSIS