M50 520i Coils

[courtster]

Hi there

A few weeks ago we picked up an e34 M50 engined 520i for a banger rally we are doing to Prague called Czechwrecks

Well the car is great - a bargain for less that £100! It just has one little fault, a slight misfire under load.

Well I've bought new plugs, 6 2nd hand Bremi coils and a valve cover gasket as there is a little oil in the plugs that I will be fitting in the next couple of days. But upon inspecting the engine I noticed that 4 of the 6 coils are earthed and 1 & 2 aren't.

#6 earth strap
#5 bracket connecting to #6 and #4
#4 bracket connecting to #5 and #3
#3 earth strap
#2 nothing
#1 nothing

the last 4 coils are the original coils (the ones that fail, I can't remember their name) and 1 & 2 are Bremi coils, both with different part numbers. So have obviously been changed at some point in the past.

So my question is, do coils 1 & 2 have to be earthed?

A very long winded post, but i thought I'd give you as much info as possible.

Thanx in advance

Courts

[Steve525]

Have a 92 M50 525 and the wiring is as you describe. I know it looks odd but mine is running perfectly like that. I replaced all my original coils with a second hand set of Bosch coils and it eliminated the misfire under load problem you describe.
I had no oil at base of rubber boots but I hear that can be a problem also!
Steve in Ireland.

[courtster]

Have a 92 M50 525 and the wiring is as you describe. I know it looks odd but mine is running perfectly like that. I replaced all my original coils with a second hand set of Bosch coils and it eliminated the misfire under load problem you describe.
I had no oil at base of rubber boots but I hear that can be a problem also!
Steve in Ireland.

Brilliant, thanx for your response