Gurus, do M50 coils RELY on ground from the valve cover?

[Jon K]

I am having bizarre issues with my standalone ECU and the stock coils. I powdercoated my valve cover which would probably alter if not negate the ground plane of the valve cover - do the stock COP coils NEED to ground through the base? Ie. do the secondary windings need the valve cover as ground?

[winfred]

nope, they will fire without being bolted down, i suspect they are nicely grounded to the cover to help prevent the brain getting zapped if a coil barfs (doesn't always work)

[Jon K]

Winfred do you know where the grounds for the coils and +12v for the coils meet said ground point and +12v point in the car?

[winfred]

it should be on the etm, if you don't see it it may route though the computer, its been a while since i had to trace one down


Winfred do you know where the grounds for the coils and +12v for the coils meet said ground point and +12v point in the car?

[fujioko]

As I recall the valve cover is electrically isolated from the rest of the engine. The ground straps attach from the studs on the head to two or three points on the valve cover. Go ahead and ohm out the valve cover with the ground straps disconnected. You’ll see a reading in the infinity range.

The lack of a ground on the valve cover will not effect the secondary side of the coil (high voltage side) because BMW provided a path for the secondary current to flow. This is why your coil has a three point connection.

Probably a good idea to keep the valve cover grounded in event you have a stray eddy current or possible charge build up. May effect radio reception or something.

[fujioko]

As I recall the valve cover is electrically isolated from the rest of the engine. The ground straps attach from the studs on the head to two or three points on the valve cover. Go ahead and ohm out the valve cover with the ground straps disconnected. You’ll see a reading in the infinity range.

The lack of a ground on the valve cover will not effect the secondary side of the coil (high voltage side) because BMW provided a path for the secondary current to flow. This is why your coil has a three point connection.

Probably a good idea to keep the valve cover grounded in event you have a stray eddy current or possible charge build up. May effect radio reception or something.

[Jon K]

Thanks guys - it seems my problem is more complex than a simple valve cover.

Hrm.

[ryan roopnarine]

jon, i don't know if this will help you any, but i have a complete, extracted dme+fuel rail+injection wireharness from a non vanos m50 at the house in orlando, if you want me to take pictures of the whole thing in segments the next time i'm there, i can.

[Jon K]

Ryan that'd be awesome!

I pulled the cover over the fuel rail but obviously not too much to be seen.