Jesse
Well Known Member
I just upgraded a panel 9n an RV-6A with an AFS5600. I noticed when flying it prior to the upgrade that there was a significant rpm drop when turning off the electronic ignition and there?s was a little roughness. Otherwise it ran beautifully and flew great. Upon testing the new installation I noticed the same thing, except I also saw that 2 egt?s dropped significantly when going mag only. At idle it ran quite rough, but not too bad at runup rpm. The short version is that the plug wires from the mag to cylinders 2 and 4 were backwards, and had obviously been like that for a very long time. Engine has been running on only 6 plugs for years, and possibly a lot of years. It has passed Condition inspections for harness doesn?t have te cylinder number stamped on it like most do, so it was never caught. One moral of the story is to understand the benefit of having 4 cht and 4 EGT probes. This could have been a huge amount of troubleshooting without that indication
Another example of the benefit of indications on all cylinders is that a friend with a 206 recently spent $11,000 in labor and parts while trying to fix an engine that started running rough at full power. Turns out that one of the mufflers started coming apart and clogged the exhaust pipe. A full engine monitor would have shown a similar EGT drop at full power on the cylinders on that side of the engine, which would likely lead directly to the exhaust being on the short list of things to inspect.
Another example of the benefit of indications on all cylinders is that a friend with a 206 recently spent $11,000 in labor and parts while trying to fix an engine that started running rough at full power. Turns out that one of the mufflers started coming apart and clogged the exhaust pipe. A full engine monitor would have shown a similar EGT drop at full power on the cylinders on that side of the engine, which would likely lead directly to the exhaust being on the short list of things to inspect.