Did you folks know your spark plug is now an engine sensor?

If what I've read is correct:

1. H-D uses the Delphi system for its electronics control of EFI.

2. The Delphi system uses ion sense technology (IST).

Spark plugs are more important than ever before; and play an important/problematic part in engine mapping.

Read all about IST here:

http://www.searchautoparts.com/motor...nse-technology

Good Forum discussion about engine knocking issues related to IST when you modify your mapping.

https://www.hdforums.com/forum/engin...explained.html

 

ION sensing knock retard strategy has been in our HDs since 2002, when Delphi took over the engine management system from the Magnetti Mareli system which had no knock detection.
The ION system works surprisingly well, even when applied to modded engines.
Not perfect by any means but adequate for 90% of applications.
Now (M8 only) we have actual piezo knock sensors, which are basically speakers, bolted to the engine.
It will take a bit to learn and tune these sensors for best performance. Dyno guys will figure it out in no time.
Bob

 

the piezo sensors are way ahead of the ion system and is used in industrial applications. they are way quicker in response and can be tuned to certain frequencies as some engines are inherently noisy. the ion only responds to electrical conductivity. they do make good sensors to monitor plug life, current draw and voltage. chamber conditions can fool them.

 

....and here is also a flaw in tuning for certain freqs. Change up the engine config and we can get false knock. Been a problem in the force induction auto world for years.


Industrial applications and Harley applications, with a flooded aftermarket world of go fast, is a bit different.


I personally like the ION system on HD's. Different cals can have the sensitivity turned down a bit and you also have some control with gap.

 

Here is some Delphi info on ION Sensing-

Delphi Ionization Current Sensing Ignition Subsystem
http://bmwmotorcycletech.info/ioniza...-susbystem.pdf

 

well each engine mfg uses what it deems good for the over-all operating conditions. just like O2, they have wide range also. a petty car engine is no match for industrial compressor belting out 2K hp 24/7 under demanding and varying loads. also, the windows can be altered so transit loads do not give false readings.
the ion sense goes back decades, only hit the auto/mc world of late. we ran altronic systems on many of the engines.

 

Hello

Could you tell me which model of HD (model name and number) uses Ion sense for knock detection ?

 

 

Thanks a lot for your reply. Could you suggest me one model of HD which uses ion sense for sure as there are many models using Twin cams as prime mover