Spark Plug Wires Question

[mrfatboy]

While trying to diagnose another issue I noticed when I pull my spark plug connector from the spark plug while the engine is running I get a spark from the outer metal casing of the connector and the engine block.  All six connectors do this.  These are 2 year old wires and connectors. All wires look good.  I would have thought the metal housing would have been insulated, correct?  Is this an inductions problem?

I measured with an ohm meter and I get 1 ohm from wire to spark plug connector.  I also get 1 ohm just on the rotor cap connector. When everything is connected I get 2 ohms. is that correct?

I also do not get any continuity on the metal casing and the wire.  Again, induction?

Is this normal?  If not what could be the problem?

I have attached the picture of both sides of the connector.

The model of the connector and wire is:

Bremi
Germany
10210/1
1k ohm

[Tyler S]

Hi mrfatboy, On your car, I remember this happening even when the boot was connected to the spark plug. If I recall it was on cyl #5. There may be somthing going on with the insulation under the metal jackets. I cant remember if you had non-resistor type spark plugs or not. I have a spare set of wires and non-resistor plugs we can try out.

[mrfatboy]

Hi Tyler, 

Fantastic. It happens on all cylinders.  Maybe these are the completely wrong set?  It would be great to try yours before I buy a new set.

I will send you a text. 😀

[66andBlue]

Hi fatman, 
I remember we bought those connectors (BERU not Bremi?)  here: http://www.beruparts.com/
they are non-resistor (1 kOhm) and if they have an insulation problem I would bring them back.
The manager is very helpful tries to do things right.

[Tyler S]

Alfred, yes the distributer connector ends on his set are Beru. The plug ends are Bremi. Have had a few issues with the Bremi brand on my VW and others. Its the same exact end supplied by various sources for our cars. The rubber under the metal shield twards the top is very thin and it doesnt take much for them to erode and carbon track to the metal shielding.

[66andBlue]

Hmm Bremi?
I always bought Beru ZLE121 or ZLE130 from them (depending on what was in stock): 1 kOhm, about 128mm long
never had any problems with them. I thought he bought the same.

[Shvegel]

Um, if you are removing spark plug wires on a running engine at the spark plug end the 30,000 to 50,000 volts generated by the ignition coil is going to try and find a path to ground.  The insulation on the plug end is only good enough to insulate up to the firing voltage of the spark plug and a bit more. It is either going through the side of the boot or through the side of the wire whichever path is of lesser resistance.

It is a better practice to remove spark plug wires from a running engine from the distributor end.  That way when the gap between the wire and the cap gets too large to allow the spark you will be holding a spark plug wire that is carrying no voltage rather than one with 50,000 volts seeking a ground.  I learned this as a teenager when working on a very high energy ignition system.  I pulled the spark plug wires at the plug end and when the gap was great enough the energized spark plug wire found a groung by traveling across my insulated pliers, up my arm, down my body and to my manhood that was resting on the fender.  Very painfull lesson.

[ja17]

Hopefully you are not erasing any good memories with your "electric shock treatment" Pat!

Anyway, most likely the wires are OK the high current is just finding a way to ground as you suggest. The current is traveling to the end of the plug wire and at that point it jumps to ground wherever it can. Problems happen when is when the current cannot reach the end of the spark plug circuit.

[Benz Dr.]

It won't be 50,000 volts though. More like 25,000 and that's with the red coil. I prefer not to have the resistor on the distributor cap. Also, check to make sure you have a metal core coil wire. A lot of new sets have a carbon core coil wire which will really give trouble.