neuroptic

I pulled my plugs in my 854KS today they are Bosch 3 prong plugs. They were real black with black soot, not oily but like dusty. Should I replace them with good old 1 prong plugs.

jim

martinlatimer

that might be the wrong thing to do i dont really know

gmbchef

or could be running lean. check your duty cycle, clean and re-gap the plugs.

maxh2o

Sounds like you maybe running lean. I'd switch to the two prongs just to be safe.

neuroptic

What is the duty cycle, how do I check it?

StormChaser404

Soft, black, sooty, dry-looking deposits indicate a rich air fuel mixture, weak ignition or wrong heat range spark plug (too cold). These carbon-based deposits are conductive, much like oil fouling, and will allow the voltage coming out of the center electrode of the spark plug to track down the core nose rather than jumping the gap. This will result in an engine misfire and further aggravate the carbon fouled condition. Check for correct plug heat range. On fuel injected engines, check for sticking injectors, malfunctioning cold start valves and/or circuits. Also check for correct fuel pressure specifications. On computer controlled vehicles, the "limp home" computer mode will always result in a rich condition. Therefore, it is imperative that you check the operation and condition of the on-board computer system. On carbureted vehicles, check choke and choke pulloff, high float level, and needle and seat condition. On all engines, severe vacuum leaks can decrease manifold vacuum, resulting in a rich condition. Weak and/or damaged secondary ignition systems will fail to spark across the gap lowering combustion chamber temperatures and promoting carbon deposits. This condition could also result from continuous low speed driving or poor cylinder compression.

tankman86

just curious i do occasionaly on the track but i hit the limiter befor the redline and i dunno why

RS4000

back in the days before fuel injection, if you drove your car at low engine speeds all of the time, carbon would build up from the unburned gas caused by the carburator. in fuel injected cars, it doesn't make the slightest difference.
the idea is, redlining would blow the carbon off the plugs... it doesn't, but that's the idea.

RS4000

you don't gap multi-prong bosch plugs