ALOT of people have asked for this so I'll just post it now. I got the idea from the DSM website but I don't like the exact way he did it so I'll write up my own version. Pull the fuel pump fuse in the dash and run the engine till it dies. This is to release fuel pressure. The reason for this will be explained later. Take a can of aerosal combustion chamber cleaner and spray out some into a container that won't melt from the solvents. Perferably not plastic. I used a Pyrex beaker. Remove the spark plugs and store them for the time being. I used a vacuum line threaded through the spark plug hole to pour the combustion chamber cleaner into each cylinder. I wouldn't recommend just dumping into the spark plug wells. Give each cylinder about 3-4 table spoons full. Put the plug wires back so it keeps any debris out of the cylinders. Wait atleast overnight to let the combustion chamber cleaner do its thing. The hard baked carbon just will not come off otherwise. After the wait. Crank the engine over several times to blow out as much of the combustion chamber cleaner as possible. Reinstall the plugs and crank a few more times with the throttle at wide open. We're still trying to get rid of the combustion chamber cleaner at this point. If we did this without relieving the fuel pressure we would probably flood the catalytic converter with raw gas and likely ruin it. Reinsert the fuel pump fuse. Crank the engine over a few times with the throttle wide open. I wouldn't recommend cranking continuously since it would overheat the starter motor. Crank a few times and let it rest. With the throttle at WOT. It takes a while to get the motor to fire up again so don't panic. Just be patient and keep at it. Eventually the motor will stumble back to life and run normally. Go for a brisk drive and let the motor idle for a while. Use the rest of the combustion chamber cleaner and spray it in through the PCV hose into the intake manifold. Not into the valve cover PLEASE! Empty the can into the motor as fast as possible and shut the engine off. Let the cleaner do its thing for an hour or two. Go for a drive again. Do an oil change. Thats IT! I tried applying a few cans of combustion chamber cleaner through the PCV hose but that only cured my problem for a little while. The pinging would always comeback and I could never break 21MPG. The ping I had always came once the motor warmed up. That told me the problem was heat related. The carbon build up retains heat and acts like a glow plug igniting the mixture at the wrong time. I've tried just about everything and this is the ONLY thing that has worked for me so far. I tried the fuel induction service at the Nissan $tealership and even they failed to clean the carbon off. Cost me $144 bucks Canadian. :-( I think I probably ran like 5 bottles of Techron concentrate, only to get temporary relief from pinging. You can do this method at home for a couple bucks. After this procedure I'd probably recommend a oil change since the combustion chamber cleaner does tend to seep through the rings and down into the oil over night. If any of this is unclear ask me personally. If you are unsure of what you are doing don't try it and come crying to me after you messed up. Kenichi 94' Sentra E Ga16DE www.importpartsplus.com
