Testing coils on a coil over plug system?

Ed Wright · 09-16-2011, 08:49 PM

If it is better with a muffler, it makes me wonder, is it in closed loop? First, that is not what you want. Second, if you insist on closed loop make sure you have the minimum closed loop RPM to something like 4000 RPM. You DO NOT want the ECU making fuel corrections at lower RPM with open collectors. Pulling oxygen back in the collector during the overlap cycle with big race cams. It will make false corrections due to the O2 "seeing" thar oxygen and returning a false lean indication to the ECU, causing a very rich mixture.
Are the spark plugs black after an extended idle?

09-16-2011, 08:49 PM	#15
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Testing coils on a coil over plug system? If it is better with a muffler, it makes me wonder, is it in closed loop? First, that is not what you want. Second, if you insist on closed loop make sure you have the minimum closed loop RPM to something like 4000 RPM. You DO NOT want the ECU making fuel corrections at lower RPM with open collectors. Pulling oxygen back in the collector during the overlap cycle with big race cams. It will make false corrections due to the O2 "seeing" thar oxygen and returning a false lean indication to the ECU, causing a very rich mixture. Are the spark plugs black after an extended idle? __________________ Ed Wright 4156 SS/JA