Changing Spark Plugs and Checking Spark Plug Condition
Spark plug replacement procedure with gap specification and torque, plus a diagnostic table for interpreting plug condition to identify engine problems.
Vanskelighetsgrad: Enkel1 min lesingGjelder for: 944 · 944S · 944 Turbo · 924S · 968
Last ned fabrikk-PDFDenne prosedyren er ikke oversatt ennå og vises på engelsk.
Changing Spark Plugs
Tools
- Spark plug socket
- Ratchet
- Torque wrench
- Engine oil
Procedure
- Check the gap on the new spark plugs. Most Bosch plugs come pre-gapped but should be verified. The gap should be 0.7 to 0.8 mm (0.028 to 0.031").
- Coat the threads of the new spark plugs with a light coating of engine oil.
- Disconnect the first spark plug wire. Replace one spark plug at a time to avoid mixing up the plug wire order.
- Using the spark plug socket and ratchet, remove the first spark plug.
- Install the new spark plug and torque to 18–22 ft-lbs (25–30 Nm).
- Reconnect the spark plug wire, making sure the connector is fully seated on the spark plug.
- Repeat steps 2 through 6 for the remaining spark plugs.
Checking Spark Plug Condition
| Plug Appearance | Condition / Cause |
|---|---|
| Brown to grayish brown with a small amount of electrode wear | Normal |
| Dry black (carbon) deposits | Mixture too rich or spark too weak. Can cause miss or hesitation. |
| Oily deposits | Leaking valve seals or piston oil ring. Can cause miss or hesitation. |
| Brown to grayish brown with obvious electrode wear | Spark plugs are worn and should be replaced. |
| Excessively worn electrode with no deposits; white insulator | Engine mixture too lean; spark plug heat range too hot. |
| Heavy tannish deposits | Valve guide seal oil leakage into cylinder, or gasoline additive buildup. |
Emneord:spark plugsignitiongapmaintenancetorque specs