To start out, let me say I may have been guilty of parroting potentially incorrect information. I was always under the impression that ANY plug other than stock 6R12 would disable the anti-knock (aka ion sensing) system. I am not sure that is true.

To that end, I need a definitive answer. I have asked 3 HD shops and nobody knew FOR SURE. So, if you can point me to, or paste, any official information on the anti-knock feature and which plugs HD says will work, please do so. And please, none of this "my friend's brother's uncle is a harley dealer ......" stuff.

 

Why even worry about it? Just use the stock plugs. Don't fall for all that snake oil crap out there. I've never been convinced that a plug will make that much noticeable difference in performance, or anything else for that matter, on a street motor. Only my .02 of course, but just curious why that question even really needs an answer.

 

Changing to non-stock plugs and/or coil wires doesn't disable Ion-sensing, it just skews the results that the sensor sees... and thus sends an incorrect advance/retard command to the ECM. The irony here is that although those super conducting plugs or wires may result in a stronger spark, the resisitive change could actually result in less power due to timing retard. More info here and here.

Bottom line IMO...
Unless you have done extensive motor work (e.g., small LSA cams, raised compression, forced induction), you are better off with stock ignition components. You can disable the Ion senor by disconnecting pin-B (GY/BE wire) on the coil connector, though it will probably throw a code. Since the Ion-sensor is basically a per-cylinder knock detector, you'll also need to make other precautions to prevent knock (e.g., SERT w/ dyno tune). It just seems like a big pain in the ***, with very little payback. YMMV.

 

Thanks. I run stock plugs now in my stage 1, but see a bit of fouling due to a slight rich condition. The SE plugs claim to fix that. I will be putting in an SE-204 in two weeks and getting retuned. If I am goin to go with a different plug, I want to decide before the dyno.

I guess it bugs me that the freakin service departments of HD dealers, who do dyno tuning no less, do not know this answer.

 

This quote was lifted from another thread. It is supposedly a response from either a Delphi or Harley engineer. Note that I added the bolding to the text.

"Regarding the OEM Champion plugs the resistive element that they use is not a resistor; it is a semiconductor suppression element. The effective resistance is specified to be 6k-15k. Furthermore, there is a fairly strong negative temperature coefficient, so the resistance decreases at normal operating temperature. In my experience, I have typically seen it in the range of about 2k-5k when the engine is running.

Note: Because the suppression element is not a resistor, it cannot be reliably measured with a conventional ohmmeter. The resistance of the element must be measured in an apparatus that provides 1000V pulses (per conversation with a Federal Mogul engineer).

You made it clear that this is all the information you wanted. However, if you want some insight into the ion sense system and related trouble codes, you may read on.

With regards to ion sensing, there is absolutely nothing magic about the Champion suppression element. Any trouble codes that you encounter have nothing to do with the resistance of the spark plug. Our circuit is designed so that we can tolerate a very wide range of resistances. We can easily operate with spark plug resistances from zero to 20k.

The ion current that we measure is in the range of 0-50 microamps. To avoid ion sense related trouble codes, you must have perfect continuity from the ignition coil to the spark plug tip. We have trouble codes P1353 and P1356 (front and rear cylinder, respectively) that are detected if we see no ion current under high speed/load conditions (where the ion current should be strongest). These codes will detect an open circuit in the ignition secondary circuit.

Additionally, we have trouble codes P1357 and P1358 (front and rear cylinder, respectively) that are detected if we see excessive noise on the ion signal. The intention of these codes is to detect an intermittent terminal.

We went through a lot of evaluation of spark plug wire terminals in order to select the one that captures the Champion terminal profile the best. Different plugs have different terminal profiles, so I suspect that’s where the issue is. I recommend “adjusting” the plug wire terminal with a pair of pliers. "

 

This sparkplug techno article is funny stuff. I have more important things in life than loosing sleep over what sparkplug to run (or not run) in my HD . IMO I prefer NGK's as I am observing much better electrode longevity vs. The OEM HD pluds. Just had my bike dyno'd and pulled perfect hp, no "DTC's", and zero detonation issues with the NGK's. (and BTW my engine spent the better part of 90 min. totalling about thirty 6200 rpm dyno pulls ) But who wants to see a "Jap" plug making clean , long term reliable service in their Harley anyways?

 

You are right. Most people could not care less as long as their bike runs fine, and for the most part that includes me. But the Engineer in me really wants to know the REAL answer. OCD.

 

Plugs are plugs, run whatever brand you want just keep the heat range the same.
HD plugs are nothing special except for the logo on them.

Most of your cars for the past 10 years have knock sensors. I bet 95% aren't changing plugs or wires with manufacturer parts!

 

anybody know any thing about Pulstar he1it Spark Plugs?

 

My $0.02 on plugs, just completed my 20K mile maintenance schedule on my Fatboy. Chart said change plugs so I added stock plugs to my list of parts from HD. When I pulled the old ones off the bike I noticed they were Autolight plugs not Harley. Put the new (stock) ones on and completed the work. Rode it to work yesterday and didn't notice anything. My bike (drivetrain) is stock except for air and exhaust so I'm not sure I would expect to see any difference.