Knock creates a pressure oscillation in the combustion chamber that is reflected in the current measurement.

I copied this from your link very good. so basically it does not measure the resistance of the plugs or wires , but it is using the spark plug as it were as a sensor measuring what is happening in the combustion chamber.

 

You must be a rocket engineer?..

 

Yes, it measures current, this is why having the proper ignition components in place is important.
According to the ion sensing info I've read engineers are looking at using ion sensing to control spark timing and fuel mixture, as well as detecting misfire and knock events.
This looks to be one of the biggest automotive tech breakthroughs in years. If engine designers start basing the whole engine tune off of ion sensing it would radically change the way engine tuning is done.
LOL no, I'm an auto tech with 25 years under my belt

 

I read this thread just for fun; I am EFI challenged. However the read did make me realize how much I love my carbureted all bore 107" motor in my '02 FLHT; 122TQ/110HP; 100TQ by 2000 rpms, 87octane and no knock. I do get some pinging when south Texas heat kicks up near 100* but I can hear the ping and start running 93 octane to solve the problem.

 

Yes that is why a lot of cars don't have cam and knock sensors , their is a spark plug in every cylinder they can use to monitor that cylinder. and adjust spark and fuel. All because of computers.

 

You are lucky this stuff is getting more complicated all the time cause of the epa and the government wanting less emissions and better fuel economy.

It is tough cause people think you just hook your scanner to the car and it tells you what is wrong! Wrong you still have to test those sensors and check those wires and voltages and resistance.

 

Yes you are lucky, but their are some people that think carbs are complicated.
I wish I had a carb on my bike, it would have been tuned by now.LOL...

 

+3 on the carb.

 

Minus one on the carb. Got to keep in mind that the engine life is 1/3 less on most carb engines. It is due to the fact that most of the time, a lot of wear due to cold start rich fuel ratio mixtures washing the lubrication from the cylinders. Fuel to air ratio on a carb from idle to wot is stone-age crude compared to a computer controlled injection system. Even my 04 without oxygen sensors has hundreds of variables in it throughout the range.

 

I would have to call BS on that statement; show me the supporting data. If one is judicious in the use of the fuel enrichener on cold starts, I say that the carbed motor life is not shortened by 30%; I might buy 10% but not 30%. Even so, a small price to pay for the convenience. I have made three cam changes, two exhaust changes, two head changes on my all bore 107 without a visit to the local dyno tuner. When I finally had the configuration I wanted, I paid $30 for a couple of pulls on a dyno to dial in the main and the needle settings and I was done; hard to do that with EFI.

I would not argue that I could probably squeeze another few TQ/HP from the motor with EFI but the marginal increase, for me, is not worth giving up the convenience afforded by a carbed motor; each to his own.