I've discovered oil on two of the four spark plugs on my D15. My guess is three reasons; blown valve cover gasket, blown head gasket, or compromised piston rings. The oil is only on the threads of the plugs. Since it was across two plugs I figured it wasn't the piston rings; however my guess is the guy who owned it before me raced it.

I've also noticed a drop in performance; granted it is a tiny engine I doubt I should be doing around 3,000 RPM while only doing 70mph. A DTC came up with OBD1 code 43: fuel system. Any ideas of what this might be?

Any help, tips, or information is greatly appreciated! Thank you!

 

Replace the o2 and throw a new set of plugs in it, then go from there.

 

You sure? I don't mean to be naive but it doesn't sound to me that a simple change in spark plugs will stop oil from getting into my cylinders. Granted, I was going to change them anyway, but not after until the oil problem is solved.

 

How many miles?
Maybe just a valve adjustment?
Valve guides or valve job? (Worst case)

 

115,000. A friends' OBD1 reader came up with a bad oil sending unit and faulty o2 sensor. Guess I'll be doing that then, as well as buying a new valve cover gasket set. Though that probably just solves the DTC portion of my dilemma... If the new valve cover gasket set doesn't do the trick then I'm going to assume it's a head gasket or piston ring, yet before I took off the valve cover there wasn't white smoke coming from the exhaust/burning oil.

 

make sure the set you get has the valve cover spark plug tube seals it is not uncommon for these to leak and soak the plugs in oil