Cylinder 5 misfire

[ahlem]

Good Afternoon,
2001 3.0 165000 miles has had the cylinder 5 misfire twice in the last week when idling at a stoplight after driving a few minutes at 45 + mph.
On the first occasion I also got the exhaust cam position sensor as well.
Fortunately I had my scanner in the car and could reset the codes.
I do notice a bit rougher idle than usual.
My thought is to swap coils and see if the problem follows.
Any other ideas or similar past experience?

[crystalworks]

I'd take your path and start by moving coils. If no change and I'd move plugs and return the coils to original cylinder.

[andrewwynn]

If you actually got a cam sensor error that's a unicorn for sure. Replace that asap.

I had to replace a couple coils on wife's x when chasing some regular misfires but they didn't finally go away until I ran some Lucas injector cleaner.

Pull and clean plug. When they misfire they tend to get pretty gummy.

[ahlem]

Swapped coils and problem stays at cylinder #5.
The plugs were changed about 40,000 miles ago and plug #5 looked good. I changed the plug and still get the same message.
I have a Foxwell scanner and would love to get a list of values and directory of the tests and where they are located.
I also have a Bentley manual so hopefully the test values are there some where.
I tried to loosen plug 1 to change all the plugs and the torque to loosen it is pretty high.
is this a penetrating oil solution? Plug 5 came out as expected. Do I use anti seize on the new plugs?
Any other thoughts on my misfire?

[andrewwynn]

I use anti seize when installing plugs. Partly based on some crazy high torque values to remove.

I have a small impact wrench that I will used to release frozen parts and it’s less likely to strip than high torque however if the ceramic breaks it’s absolutely imperative that you find every crumb since BMW engines are interference engines. A buddy of mine didn’t notice that the ground electrode broke off a spark plug and fell in and now he’s got a dented rod bearing and the lovely associated knock.

I was chasing seemingly random cyl misfire on wife’s x until I swapped out two of the coils and additionally ran some Lucas injector cleaner. Problem finally disappeared.

[crystalworks]

Originally Posted by ahlem

Swapped coils and problem stays at cylinder #5.
The plugs were changed about 40,000 miles ago and plug #5 looked good. I changed the plug and still get the same message.
I have a Foxwell scanner and would love to get a list of values and directory of the tests and where they are located.
I also have a Bentley manual so hopefully the test values are there some where.
I tried to loosen plug 1 to change all the plugs and the torque to loosen it is pretty high.
is this a penetrating oil solution? Plug 5 came out as expected. Do I use anti seize on the new plugs?
Any other thoughts on my misfire?

What plugs are you using? NGK's come with anti-seize already and are the only brand I use for BMW's. But I would definitely use anti-seize if not done from the manufacturer on any plug you do use.

Is cylinder 5 missing the only code you are getting? No more cam sensor errors? I think the only other thing specific to that cylinder besides the plug/coil would be the injector or head gasket. Thoughts Andrew?

Running some Lucas isn't a bad idea even if it doesn't change anything. I throw some in a couple of times a year when I fill up.

[upallnight]

If swapping the coil and plugs didn't care the misfire next step will be a compression test to determine if perhaps you have a bad valve or some other problem.

[ahlem]

Update... I swapped out the coils and put in Bosch plugs. That really smoothed out the general running at anything but at idle. When I'm first starting or just sitting at a stoplight it's like your AC compressor turns on and there is a shudder and I get a Cylinder 5 misfire code. Once I got a Cylinder 4 misfire code as well. It's feeling like a vacuum issue is causing a lean-out at idle. What idle related vacuum components could be playing with me? Idle Control Valve and cracked vacuum hoses come to mind. There is also a "Chuffing" sound after I turn off the car. Is this a possible indication of a failed DISA (what ever that is) valve?

[andrewwynn]

I usually get the "cough" from my M54. Never figured out what it is but my guess is actually just some Cylinder just past the compression stroke venting either out exhaust or backwards into intake.

Realtime measure of fuel trim and other data will help a lot. What scanning solution do you have ?

[andrewwynn]

I'm not aware of any idle/vacuum connection. X5 uses DME to simulate the concept of vacuum idle control as far as I know.

Get some fuel trim numbers and go from there.

My fuel trims went to pegged max when a pre cat sensor heater died. You need to figure out what your fuel trims are