I tried starting it again and the engine refused to run?

I was also told that I would need a camshaft locking kit to remove the cylinder head, as it was suspected that there was a failed cylinder head gasket. This tool arrived last week too which I had purchased again from eBay for $38.00 plus shipping.

So, the next step is to first test the new coil and then remove the cylinder head, which I am not really looking forward to as this is the first major type of job I have done on any car. But with your help it will not be as daunting as it could be!

This thread has been truncated somewhat as I have re-written most of it from memory and Joe's posts have not been included here because those were lost.

Well, I am a bit bummed out as I discovered that the coil on #4 cylinder is not the issue. I tested the new coil on #4 and there was no spark. I tested it two or three times with the same result. I then put it on #3 cylinder and there was a spark. So, I put back the old coil on #3 and there was a spark, whereas before there was not. So, I have concluded that part of the wire touched the area around the engine when doing the initial test (which is bare from the connection point on the chassis at the back of the engine bay on the passenger side to the contact point inside the tube of the coil which the spark plug goes into). Oh, well.

That leaves me with only one option - the plug itself is faulty if there is current going through the green wire when the key is in the 'Start' position but not engine on. I am wondering if it's possible to just get that part. Will keep everyone informed.

Hi Joe,

Its the valve cover gasket I meant with regards the oil being found at the bottom of the spark plug tower. The oil is seeping into some of the tower holes at the point where in some of the holes the gasket has been pinched between the valve cover and the head (in other words, some of the gasket is protruding into the spark plug tower and is wet due to the oil leaking through).

One thing I failed to mention which may shed some light on why cylinder #4 spark plug electrode is not working. The first issue I came to this forum with was my car would turn over but would not start. After much trouble shooting it was discovered that the ECU (or DME as it is also called) had been fried due to water ingress into the compartment where the ECU/DME was situated. After I got a replacement ECU/DME from Europe somewhere I got a new set of plugs and I remember that ALL the old ones showed black carbon on them - which means that all of them were firing. After installing the plugs and the ECU/DME the car started right away but I never pulled the spark plugs after that as I thought everything was working.

So the issue with spark plug #4 not working may have something to do with the ECU/DME being faulty on that cylinder.

OR it could be the actual plug that plugs into the coil is at fault because there was power going to the green wire in the plug when I did that test a couple of weeks or so ago. I tested for current in the green wire on the outer part of the plug where the wire came into the plug, not at the actual connector which plugs into the coil.

This particular model has three wires going to the plug - green, black and brown.

I'll have to go and purchase a testing light.

Ok. Thanks for that. I should have this tested in the next couple of days.

Hi Joe, sorry about not getting the next step done sooner but I have just done the step you requested this evening. Not good news. I will let the videos do the talking.

First up is a test cylinder (cyl 3 from the front counting back). I purchased some extra wire and alligator clips and rigged the test probe so that the metal probe itself had an alligator clip with a wire going from the probe to the brown wire with the alligator clip at the other end of the wire stuffed down into the area where the brown wire from the ECU went in the back of the plug. The wire embedded within the probe went to the green ECU wire going into the plug with the alligator clip stuffed down that hole. That resulted in the light in the probe being constantly on as long as the key was turned on in the ignition (engine turning over and in the on position). See video attached.

Next, I put the alligator clip from the brown wire to the black wire. This time the result was a pulsing light as the engine turned over. See video attached.

Moving to the problem cylinder (#4 from the front of the engine) I attached all the wires as before, but this time put the alligator clip from the wire on the metal tip of the probe into the black wire receptacle at the back of the plug. The light was constantly on as the key was turned into the on position and also when the engine was turning over. See video attached. This means that the ECU is faulty. :(

The same result happened with the brown wire on this cylinder. See video attached. This post is a bit redundant but I put it up anyway for continuity.

So, is there any other way to resolve this apart from either getting another ECU or getting this one repaired by one of the services that advertise such work? Or do you think I can I open the unit up myself and see what the problem is?

Hi Joe,

Thanks for responding. Okay, I will open it up this weekend (I hope it doesn't have any security screws on it) and post some pictures of the internals though there may not be much to notice.

Hi Joe,

I finally got around to opening up the DME today (Friday, 16th September 2022). Not great news. I have been sold a unit that has had water ingress. I have posted the images of what I found (just before my batteries failed) with text explanations of what one is looking at. Now it's a question of whether I send it off to get repaired or get another refurbished unit entirely (very expensive!). Considering that my original unit quit working of the same causes I am surprised that it worked at all.

As a side note I am always puzzled why manufacturers assume that water will not get into one of these units and don't encapsulate them in resin. It would save customers lots of money.

Hi Joe,

I am going to see if I can get this unit repaired. Refurbished ones seem to be around $300. I have found two places in Canada that repair these units: One place near me and another in Toronto. There is also a guy who has a field of BMWs near me too so I will call him and see how much a unit will cost or if he can recommend a repair place.