Deposits on spark plugs

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- Snowman
  
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posted
20 years ago

Fri, Sep 12, 2003 1:59 PM

'94 K1500 Suburban 350/4L60E (110,000 miles)

What would cause deposits on the spark plugs in this engine on only 3 cylinders? Cyl. #2, #4, #8 all had deposits on the plugs. #2 and #4 had LOTS of junk on them, where as #8 just had a little. New plugs, wires, cap, rotor at 90,000 miles.

All the others looked perfectly normal- nice clean burning. No green tint to the deposits (as it may be with Anti-freeze on them). Compression was good, 145-160 psi. Deposits looked to be whitish tan in color and covered the end of the plug more than half way around.

I don't run fuel additives or anything of the sort (dry gas occasionally in the winter months).

Any hints on this one?

Snowman

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- W.Rowe
  
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posted
20 years ago

Sat, Sep 13, 2003 12:45 AM

the white could be comeing from running to hot .... and the junk and white could also be from preignition.... hope this may help a lil and i hope my resources are correct!!

Bill

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- "Doc"
  
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posted
20 years ago

Sat, Sep 13, 2003 1:21 AM

Snow,

It's all on the same side of the engine, so you know what that means..........................I think your idea that the head gasket may be headed south is becoming more possible. How does the compression on 2, 4, 8 compare to the other 5 cylinders?

Doc