Looking for help,

I have a T2 serries five rx7 and are having problems with carbon buildup on my sparkplugs, So much so that it was causing a misfire.

I am running Mazda Factory oil, and NGK 9's & 7's, I run the car almost exclusivly on high octane (98) wich is the best fuel available in New Zealand. The engine is a new rebuild (about 3 thousand km ago). I have had a factory Diagnosis done on the engine and there are no apparant engine error codes.

any help would be appreciated.

 

does your car use up a lot of oil? Are the plug wires in good shape and securely fastened?

Brian

 

you need to redline it more

 

No, car uses onlywhat you'd expect, plug leads visually seem fine and come up ok when tested with a multimeter, the only vague suggestion that has been give to me is that maybe the mixture is too rich but i dont know what to do about it.

 

NGK series 7 and 9 plugs are cooler for highway driving meaning they run cooler than hotter series 6 and 8. That doesn't mean too much unless, as in your case, one sees a lot of carbon buildup on the plugs. Changing to the series 6/8 will make the plugs run hotter and burn off the carbon.

Refer to: http://www.mazdatrix.com/ign-2.htm

 

But surely something is causing the carbon to form, my understanding is that 7's & 9's are the factory spec plugs, so by running hotter plugs aren't I just masking an underlying problem?