Pete H Posted April 17, 2004 Share Posted April 17, 2004 Had a problem with a fouled plug this morning resulting in a misfire throughout the rev range. Only one cylinder though, number 1. Any thoughts, duff plug, HT lead, or injector 🤔. Plugs are NGK BCP7ES, and all seemed correctly gapped at 30 thou. Quick wire brushing and car (R300) ran fine, but plug was very black on the nose compared light brown for cylinders 2-4. Cheers Link to comment Share on other sites More sharing options...
StewartG Posted April 17, 2004 Share Posted April 17, 2004 Was it oily black or dry black? Link to comment Share on other sites More sharing options...
Pete H Posted April 17, 2004 Author Share Posted April 17, 2004 Dry black, going to swap plugs around in the morning to see if cylinder or plug specific. Link to comment Share on other sites More sharing options...
Pete H Posted April 18, 2004 Author Share Posted April 18, 2004 Swapped plugs over, still number one thats sooty. New plug lead ?, or is it just turbulent air entering the filter at speed upsetting the flow into the first cylinder. Link to comment Share on other sites More sharing options...
Chris W Posted April 18, 2004 Share Posted April 18, 2004 Peter Do you have a distributor or wasted spark coils? With wasted spark coils (2 plugs per coil), the spark on one plug fires centre electrode to earth, the other earth to centre electrode. The latter one is a less powerful spark than the former due to the physics and in some systems can become sooty after a while. However, Rover seem to have enough spark power to overcome this. So I am just wondering if one of your wasted spark coils is not functioning 100%. Have you tried swapping the coils over to see if the fault moves? I bet you'll now tell me you have a dizzy!!! Chris 2003 1.8K SV 140hp see it here Link to comment Share on other sites More sharing options...
Pete H Posted April 18, 2004 Author Share Posted April 18, 2004 Chris, Yep, it has a dizzy. I was tinkering with the idle speed when the plug first fouled. Since cleaning the plug (and getting the idle right) the misfire hasn't reoccured, but the plug is still very black compared to the others, and blackens again following cleaning it after 20 min blat. Am I worrying about nothing  Pete. Link to comment Share on other sites More sharing options...
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