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

[BMWahba]

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

Not sure what I’d be accomplishing. My cylinder 3 was wet but that was not the low compression cylinder. Logic would have it that cylinder 4 was the one that’d be wet with low compression from a wash out. But again, no clue.

[George Hill]

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

I came here to say this but jet_dogg beat me to it.

In a situation like this swapping in a "known good" part isn't something I would personally do unless it was literally right now in a running car. Say your injector has been sitting on the shelf for 6 months and something has happened to it. You put it in cylinder 3 and nothing changes... because it is also bad now your diagnostics are thrown off.

Instead swap injectors between cylinders and see what happens. IF you confirm the wet cylinder (or misfire) followers the injector THEN put the "known good" injector in it and see if the issue is resolved.

Cyl 4 & 3 are companion cylinders, sometimes something that happens to one affects both.

[BMWahba]

I came here to say this but jet_dogg beat me to it.

In a situation like this swapping in a "known good" part isn't something I would personally do unless it was literally right now in a running car. Say your injector has been sitting on the shelf for 6 months and something has happened to it. You put it in cylinder 3 and nothing changes... because it is also bad now your diagnostics are thrown off.

Instead swap injectors between cylinders and see what happens. IF you confirm the wet cylinder (or misfire) followers the injector THEN put the "known good" injector in it and see if the issue is resolved.

Cyl 4 & 3 are companion cylinders, sometimes something that happens to one affects both.

I understand. Noted. I am sending my set of injectors out to get cleaned anyhow.

[BMWahba]

An update on my Injector testing... here were the results. Any thoughts on how this corroborates with the symptoms in this thread? Cylinder 1 and 3 were dripping, the rest were in "fair" condition. Cylinder 4 was the one that had low compression...still kinda doesn't add up.

Does anyone know if the ECU averages out the fuel injection across all 6 cylinders or is it read per cylinder?

[digger]

It probably averages per bank just a guess though

[BMWahba]

That could make sense, in that it compensates for other cylinders the ones that were dripping or spraying too much.

[tlow98]

It’s read per bank. There’s only two oxygen sensors. One for the front bank and one for the rear. Changes are made per those sets of cylinders.

[BMWahba]

Yea. Who knows really what happened. About 30 miles driven on the car so far, everything seems fine.

[Tbonem3]

Drive it hard, avoid short trips and turning it off after low rpm driving/not reaching full oil temp IMO.

Recipe has always worked with my 225k e36 and 183k e46.

[BMWahba]

Drive it hard, avoid short trips and turning it off after low rpm driving/not reaching full oil temp IMO.

Recipe has always worked with my 225k e36 and 183k e46.

Or maybe it's a sign to just let her go!

[y2k_o__o]

Yea. Who knows really what happened. About 30 miles driven on the car so far, everything seems fine.

To OP, any update 4 months after the injector cleaning?