Misfire - Wet Spark Plug on Cylinder 3, But Cylinder 4 Low Compression...

[Tbonem3]

and I don't beat on it

Think I found the problem. Just j/k, sorry you're having issues Michael.

[sapote]

“It sat with "oldish" fuel in it, that was the worse thing that happened. And that fuel was about 6 months old, max.”

A year old fuel is nothing to worry about.

[BMWahba]

“It sat with "oldish" fuel in it, that was the worse thing that happened. And that fuel was about 6 months old, max.”

A year old fuel is nothing to worry about.

Ha, that's what I thought but here we are..

[sapote]

Ha, that's what I thought but here we are..

Fuel is a very good solvent, new or old. You're thinking it's like thick paint. How do you know the leaking injectors are due to 6 month fuel and not something else?

[BMWahba]

Update:
spoon full of oil got compression on cylinder 4 back up to 150.

so please, can someone help me understand what is going on. This is so strange.

Again for clarity: Cylinder 3 is the one that I would suspect a “wash out” considering it was visibly wet. But cylinder 4 is the one I had a low compression on. After adding oil, on a cold compression, all cylinders are reading 150.

How can I rule out a piston ring issue at this stage?

for safety, I am swapping all 6 injectors with a used spare set.

[BMWahba]

Another question: is there any validity to a possible coil pack failure on one or more cylinder to cause injectors to keep firing and thus cause some of these strange symptoms?

[tlow98]

Hence my extreme frustration, sadness and confusion all at the same time. This car was running perfectly and I don't beat on it. It sat with "oldish" fuel in it, that was the worse thing that happened. And that fuel was about 6 months old, max.

I tested it twice cold, one at 98 and the other at 102.

I am doing the oil spoon method today. Will update.

Yeah, it’s very surprising. I’m leaning toward the fact that it’s just something simple. Bad gas seems like a stretch.

You snag a borescope?

Do a leak down and see where all that “lost” compression is going.

on my engine that had a blown HG it was very easy to feel/hear the air moving into adjacent cylinders and out through the block with my worn rings. Cylinder walls looked perfect, however.

[BMWahba]

Yea definitely makes not much sense. I am going to swap plugs today, put it all back together and idle it. Then do a warm compression. The boroscope is how I got those picture of the pistons but I wasn’t able to look in the walls. The camera didn’t really fit to turn it towards the walls or it was too shiny.

[enjoy_m3]

Did you do a leakdown? Would verify the rings aren't sealing if there is no leaks on the valves.

[BMWahba]

No leakdown.

Hot compression test results after idling the car, all cylinders reading 150 psi.

so…..yeah….

[tlow98]

No leakdown.

Hot compression test results after idling the car, all cylinders reading 150 psi.

so…..yeah….

well, that’s great.

im not entirely sure what the next move in this situation it. Strange

[maw1124]

My guess is some o-ring, probably on an injector, is letting fuel wash out Cyl4 when it sits. But that's a guess from WAY far away. I wouldn't suspect a coil or plugs or rings or the cylinder itself.

Seems like a "when it sits" condition only.

maw

[digger]

You could do with an injector service or replacement and then see if the issue persists

[BMWahba]

Yes. I will be sending my injectors out and in the meantime, I put in a spare set which were verified good. I should see the results of the injectors when they get them to rebuild/test to see if they were faulty.

For now, I’ll get the car put together and drive it a bit to see how things do.

[jet_dogg]

Why don't you swap the injector with one from another cylinder?