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Top pic is as close as I can get to putting the coil in a position to attach it to the engine. If it were attached, I might stand a chance of getting the connector off.
Doing the 2nd spark plug set replacement on my 2016 E350 and have run into a difficult problem with #6, driver side (left-hand drive). I have probably spent 4 hours attempting to accomplish that. I recall that the last time I did this, it was more difficult than the others, but I was able to accomplish it in a reasonable amount of time.
The new park plug is in, but it's the coil that I'm having a hard time with. 1)The coil is attached to the wiring, and I can't get the connector detached from the wiring. The wiring to the coil there is quite short. In retrospect, had I addressed this at the start, I wouldn't have the problem. But I didn't remove ANY of the connectors last plug change or this plug change. 2)The coil is stuck below its usual location, and can't move the coil up to its place even loosely because of several other things in the way, tubes, and wiring. It is constrained on all sides.
I have attached a very good guide, but no help for my problem.
I think the answer is that I have to get that connector off the coil, but how? Appreciate any suggestions.
This is as close as I can get to putting the coil in a position to attach it to the engine
Last edited by Sunnyslope48; Sep 28, 2025 at 02:04 PM.
I know sometimes they are stubborn.
Here is how to do it properly.
Engine OFF, ignition OFF.
1st thing is to spray contact cleaner to remove oil debris which usually deposited at the latching mechanism and caused this HARD TO REMOVE issue.
Spray at the grey 1st lock mechanism and around it, so that contact cleaner get to the 2nd latch/lock which is black and hidden.
Grey first lock , it slide out ( to the rear ) to allow then the black lacth 2nd lock to be lifted up.
You need to push down/in the grey 1st lock, so that the black 2nd latch lock lever get lifted up from the locking dot at the COP.
When there are dirt, the black 2nd latch lock sometimes does not lift up enough.
This is then what you must do.........
Get a toothpick and insert it under the 2nd black latch-lock to lift it up.
Now the part on how to slide out a stuck connector is not by only pulling from the back ( grey 1st lock ), but you need more force at the front connector to push it away from COP.
This way you will not break the grey first lock.
The spray, the toothpick, although I used a small metal probe, pushed underneath the opening, and a little tap, tap, tap, and the connector slid right off and back on again. I had enough room to wiggle the coil into position to engage the spark plug. Now, again smooth as glass.
The spray, the toothpick, although I used a small metal probe, pushed underneath the opening, and a little tap, tap, tap, and the connector slid right off and back on again. I had enough room to wiggle the coil into position to engage the spark plug. Now, again smooth as glass.
Great work, great advice.
Glad this got fixed. Another tip I didnt see mentioned is pushing the connector "on" first to loosen it is addition to everything mentioned above. This is similar to slightly tightening a nut before loosening it. It break the seal and allows the clip to move on the nub capturing it. When reinstalling, dielectric grease is your friend, especially on the boots and connectors.
Glad this got fixed. Another tip I didnt see mentioned is pushing the connector "on" first to loosen it is addition to everything mentioned above. This is similar to slightly tightening a nut before loosening it. It break the seal and allows the clip to move on the nub capturing it. When reinstalling, dielectric grease is your friend, especially on the boots and connectors.
Good one, indeed true.... sometimes the black 2nd latch is tight on the locking dot and pushing forward/IN can make it relax a bit when we push down grey 1st latch and indiretly also
the rear end of the 2nd black latch under grey 1st latch.
The most unpleasant connector on the engine to remove due to heavy duty 2.8mm pins iin use and huge vacuum effect of the silicone perimeter seal is the big grey to black one, usually called 14 pin X26
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