spark plug lead (m40b18)

[wayneng]

Can someone tell me what is this thing that i highlighted in the first pic in the blue box? is it a sensor? In the second pic highlighted in red is where the other ends goes too.I am planing to change the whole set of spark plug cable but was wondering how to take this out which loop to the cable number 4. I was planing to put a performance type cable so the diameter might be bigger than this standard ones. So worried that i cannot put this wire/sensor back to the new set.View attachment 15657

 

[Fahami]

It's a signal pickup coil, signal for engine RPM or signal for ignition firing (for other purposes i.e measuring advance/retard etc.) depending on car manufacturer

 

[wayneng]

It's a signal pickup coil, signal for engine RPM or signal for ignition firing (for other purposes i.e measuring advance/retard etc.) depending on car manufacturer

So after installing new cable i need to somehow slot this in? I cannot see how do i take that off and put them on the new one.i can take that off by cutting the plug wire but how bout the new cable? And is it not posible to fit something like this?
http://www.supercheapauto.com.au/on...Lead-Kit-B6042HP-Blue.aspx?pid=154957#details

 

[GearOSv2]

According to here:
http://bmwfans.info/parts/catalog/E..._electrical_system/ignition_wiring_sparkplug/

Item 9: Pulse sensor. Like wht Fahami said, used by ECU to pick up the pulse. Usage, dunno. Hehe.

The M40 engine should not be that advance to try to correct firing... but then again... Motronic is the best of it's kind back in those days.