white plug tip

[63tuner]

yesterday, i checked all the plugs and found out that the plug tip on the first cylinder is white but other plugs are normal. sometimes i heard engine knock when starting the car in the morning. what cause this? coil? plug cable? or injector?

 

[eagle_talon90]

If the tip of the plug is white it's because it's getting too hot. You could have over-advanced ignition timing, a lean fuel mixture, vacuum leaks around the intake manifold, it could be many things, check these first though and go from there.

 

[anteversion]

yeah white tips mean lean but at idle speed

 

[1992awdlaser]

It doesn't always mean the car is running lean. I have seen stock cars in perfect running condition have plugs with white insulators. The things it could be are running lean, too hot of a plug, ignition timing too advanced, vacuum leaks, or insufficient cooling of the engine.

 

[anteversion]

white tip is not the same thing as white insulator... white insulator mean lean at wot. tip color or deposit is an indication of idle condition and timing. look at this link this is a good explanation of spark plug reading Spark plug reading

 

[STI2TALON]

White tip can also mean coolant is being burned (head gasket) from what Ive seen

 

[anteversion]

yeah thats true, but there's so many things you can know just in looking at a spark plug

 

[63tuner]

thanks for replying,, anyway, eagle_talon90 said that white plug tip happened because of intake manifold leak..can the intake manifold leak makes a white plug tip?.. but it only happen on cylinder 1 spark plug