View Full Version : BROKEN SPARK PLUGS! Help!

06-17-13, 06:06 PM
A bad series of events on my end! Pulled the cadi into the shop from it running terrible. The current tune on it was rich anyways MAFS came loose causing my air/fuel to start acting up. Thinking it was a fouled plug, we ordered 8 new ones. After pulling #8 plug things took a turn for the worse. We pulled out a broken plug. After a bore scope we noticed the cylinder was fine, the piston was lightly chewed up, but I had compression. We then threw the new plug into the threads and trailered the car to a dyno shop in Charlotte. Well they started it, and it broke the same plug! What could it be!? Now they have to pull the head, and see what's causing this. Help?

06-17-13, 06:07 PM

All advice is greatly appreciated

06-17-13, 06:27 PM
I am not sure what help you need. Assuming you are not running the wrong plug, I would assume you have a bent valve since the relative positions of the plug and pistons are pretty much fixed. In any event, the head has to come off to find out what is going on.

06-17-13, 07:39 PM
Did you compare the old plugs to the new ones? Not just by look but by measurements? I know it would be hard to see but can you tell if it sits the same height as the other plugs? Has the head ever had any work done to it? Maybe that plug location has a heli coil in it?

06-17-13, 09:06 PM
The head has never had work done to it. We're thinking they SHOULD HAVE used a heli coil after re-tapping the threads after the first broken plug. The first plug broke off some of the threads, while the second broken plug only broke the electrode/. Just something to consider. Thinking ill have them pull the head, which includes the Maggie and everything else. Then a re tune to lean it back out. Guess ill keep you posted I'm just a young troop with near 40,000 into my V. It's an05 with 32k putting 551 to the wheels. Something was bound to break

06-17-13, 09:52 PM
too much fuel maybe ... could have lifted a ringland......or something foreign in the combustion chamber all together. Either way only way to tell is to tear it down and inspect.