Hi Everyone,
Hopefully I can shed a little light on what is happening here on an Escape. There are a couple of things that it could be in addition to the coil. These coils on this engine are called Coil on Plug. What this means is the coil sits directly on top of the plug. This is a good design as it is more efficient and is actually more reliable because there are no spark plug wires so the actual spark does not need to travel as great a distance. There is just a wiring harness, coils, boots, and plugs.
The issue is, the way they are positioned in the engine. They are relatively vertical on the engine and the spark plug hole can actually hold water in it. Once this happens the boot that is around the spark plug and attaches to the coil will swell. Once this begins to swell it can cause the coil and plug to arc and it causes a misfire. This is also why they seem to misfire when it rains or high moisture. The water is getting where it shouldn't. Unfortunately, the coil gets condemn to often. Usually the coil is ok but the plug and boot are the issue.
If you have this engine with coil on plugs, I would suggest just swapping only the coil to another cylinder and then see if your misfire moves with it. If it moves, then your coil is the issue. If it stays in the same cylinder then the boot, plug, or another issue is causing your misfire, but at least you know it is not the coil.
These are very easy to move. I attached the procedure. It is literally, remove the engine cover, un-clip the coil connector, remove the 8mm bolt, pull the coil/boot assembly out. When removing the boot, you will find a long spring attached to the coil. Make sure not to damage this as this is what delivers your spark.
When reinstalling the bolt, DO NOT over tighten it. You are putting a bolt into a thread that is encased in a plastic plenum. If you strip it, you need to replace the plenum.
When putting the boot back on the coil, put dielectric grease on the opening where the spring slides back in. This will "drag" the grease down the inside of the boot and help fend off moisture.
When reinstalling the coil/boot assembly, put dielectric grease around the top of the boot on the outside where it seals inside the spark plug hole so that it creates a better seal and tries to keep moisture out.
As for the post about the catalytic converter. That is an accurate statement that the converter can be damaged due to unburned fuel and it is never a good idea to drive with a misfire for this reason. However, coolant due to a leaking head gasket and oil in the combustion chamber that get expelled to the converter are the fluids that can clog the converter. Unburned fuel will ignite when it hits the hot exhaust and it will overheat the exhaust causing leaks and internal damage to the converter.
Hopefully, this helps with some more ideas about the issue with this engine and the next time you are told that you need ANOTHER coil, make sure the swapped it to be sure the coil is the issue. Most techs that replace the coil, do not reuse the plug and boot. They get those new as well so the issue may have just been the boot but you got a coil to go along with it.
Thanks
Kenny
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Saturday, April 13th, 2019 AT 6:31 PM
