"Ion Sense", I know what it is and how it works in H-D's motorcycles and the importance of using proper wires and spark plugs......

Are there any other gear heads on here that would like to explain? And I am just trying to create an interesting and informative topic.

 

Well if you know then why did you ask??

 

I asked if anyone else would like to explain.....I didn't ask what it was, butI guess it increased your post count and mine too.

If no one responds, I will write the explanation.

Doesn't this spur curiousity in that it affects the ignition system, combustion and ecm by use of the proper wires and plugs? This is why H-D recommends its own brand of wires and plugs to supply the proper resistance, not just to increase profit.

 

Are you referring to the knock sensors?

Either way, please explain.

 

Screw the post count. Will somebody 'spain to me whadda da F@#$ you talkin' bout ?

 

It is important to use the stock wires and plugs because the ION sensing, Knock detection, whatever works off of resistance and amperage. The system is contantly monitoring the pulse out put through a given coil, wire and plug. At the point of detonation cylinder pressure increases and resistance raises and amperage slows. The system will alter timing accordingly. If you change wire resistance or plug resitance (temp range) the sytem will pick up these changes and basically shut off. It senses a malfuncion. I haven't seen too many engines that needed the stock ignition upgraded. In the old days yes.

 

Amen....Gutman....You have my utmost respect.....This is not commonly talked about and is virtually unknown but is used in the later model H-D big twins.....the coil sends a secondary 80 volt pulse to the plug after the cylinder fires and measures the resistance to ground via the ion charge left in the cylinder after combustion...the ecm works using "grounds" to control the efi and ignition system...thesesytems are altered based on what the ecm detects as resistance through the 80 volt pulse going to ground.......and thus makes what is supposed to be more efficient power. Changing to different plug wires or plugs could change the resistance value of the charge being sent and thus change the resistance value message received by the ecm.

 

I have a 2012 FLD 103" with T-Man 555s, SE Air Cleaner, gutted stock head-pipe with SE Nightstick open end-cap and 12 discs. Dyno tuned using SE Pro Race Tuner. This past winter I got bored so I installed NGK iridium plugs and Taylor 409 race wires. Ran great in the cold weather months. Now that summer is finally here in Ohio I started to notice pinging when leaving stops, especially when my old lady is on the back. This condition is worse on hot days. I reinstalled the stock 6R12 plugs; still had pinging. I added Lucas motorcycle octane boost; still had pinging. I then reinstalled the stock plug wires and the pinging was gone on a 89 degree hot day. Then I went for a ride on a 92 degree day with the old lady on back and no pinging. I plan on continuing to use the Lucas octane boost as it is a fuel system cleaner and helps with the poor "summer blend" gas we get in Ohio. I can say without a doubt that the plug wires do make a difference with the Harley ION system.

 

If a bike comes with ION sensing, swapping wires will disable the system. Going one colder VRod plug seems to work OK. I ALWAYS use HD plugs on any bike thru here. Customers are told to bring a set with them. ION sensing is why, when a plug is pulled 'to check for spark' there will be no spark. A sprk plug hung in the air has no resistance and the ECM is programmed to kill spark and fuel when a no compression event is seen. (hole in the piston kind of thing). Ion sensing controls timing to a certain degree, too. If ping is detected, the ECM will pull a little timing, for a second. If ping is repeatedly detected, long term learn will pull timing for a number of key ups... this stategy is for a bad tank of gas.

The more one moves away from 100% stock combustion events, the less reliable ION sensing becomes. The ION sensing is modelled inside of the ECM for a stock bike. Once compression is added, it starts to lose it's abilities a little bit. Compression (dynamic compression) changes with even a set of cams. And... when modelling... there is no other compression than dynamic. Static compression means nothing to ION or a rider.

But the changes are not drastic and I tune 120r and 117s all day long using ION sensing to help find ping.

It is NOT called a 'knock sensor". That was sooooooo '90s talk where a knock sensor was a microphone installed in an engine block. This system is way more than that.

Mbowman5? Summer mix gas is the good gas. WInter gas is what sucks. If you need octane boost for your bike to run right, you need a tune. Winter gas has butane in the gas. Summer gas has to be pure gasoline.

Read about ION sensing http://delphi.com/pdf/techpapers/2013-01-0354.pdf

 

Excellent information resource, Thanks! would you happen to have a similar qualified source to explain the new PV value "HeadT"? 'Cause nobody here, including DynoJet, can provide a comprehensive explanation at this point.