E30 Zone

hi

i,ve got some new ignition leads for my 325i(1991). on the old leads (lead no. 6) there is a another lead attached to it with a round plastic head (looks like some type of sensor) i am unable to replace the lead no. 6 as i can not remove this other lead with out cutting it.

can someone tell me what is this attachment is. is it important or can i cut it off and put in a new lead without it. what is the way around it.

thanks

That attachtment is important. Its an inductive pick up for the ECU.......Dont cut it off.
Im sure "Proper" leads should come with this pickup already fitted to lead #6.......

you can buy sets without the pickup so its not absolutely neccesary

On some versions of Motronic this sensor (effectively a cam position sensor) is only used to feed a socket on the diagnostic connector.
On other versions, the signal from it is used by the ECU as well. It tells the ECU whether a piston at TDC has just finished the compression stroke or the exhaust stroke.
It's unlikely your ignition leads need changing at all.

thanks

for time being i,ve left the lead 6 alone and replaced all the other 5 with new ones. the car runs much better but i still need to replace the 6th lead too. the leads i bought are high quality silicone gold plated leads and the sixth lead did not come with this attched sensor.

Fit it and see what happens!

I've removed the original leads and fitted a set of Magnecor's without that sensor, no running problems whatsoever.

The sensor lead is plugged into the engine loom underneath the diagnostic socket

Just unplug it, change the lead and fire it up. I'd put money on it working just fine.

Cheers,

Iain T

It'll work OK with the sensor disconnected, whether it's needed on your particular Motronic set up or no, but if the ECU uses the signal there will be a small decrease in performance/increase in fuel consumption.