Have a R53 getting a P0301 cylinder 1 misfire code.

Little backstory, replaced spark plugs and wires a few months ago and had zero issues. Took it in to dealer about a month ago for other reasons and they said I needed to replace the valve cover gasket and spark plug seals. I did that and still no issues.

A couple weeks after that this started occurring. It went away a couple times for like a day but then came back.

Tried swapping spark plug and also wire to different cylinder to see if they would be the culprit and it still comes back P0301 cylinder 1 misfire. Doesn't look like a lot of oil or anything got down in there. I'm a basic mechanic so not sure what else it would be? Any suggestions what else to look at? Could it be the fuel injector? I have no clue about them.

 

There is another similar thread about cyl 1 misfire and the owner has been stumped after changing a lot of parts. I would caution not to take the fault code at its face value. It is only as good as the designers that wrote the code and the limitation of the resources that are available to perform the self diagnostic.

 

Had a similar code on my MINI, did the usual things to try and fix the problem. New, genuine coil, plugs and wires. Code still came back. Then had a compression test, leak down test, etc, done, and found that it was probably a burned out exhaust valve on cyl 3.

I had new valves fitted, and the head decked (plus a few other maintenance items) by the good folks at Detroit Tuned. No problems since then.

 

This is invaluable for those having the same code.

Of course no one should assume the root of their problem is due to identical cause.

 

CRC how much did that set you back?

 

Around $2300. That was for 8 new valves, head decked, new timing chain/guides/tensioner, new thermostat, new front seal ( I think ), plus other items (oil, filter, coolant, etc.), all gaskets, and seals. There's probably something that I'm missing off of the list.

 

Code readers will only tell you so much. Other tests may have to be performed to find the root cause of the problem. It's possible to throw all kinds of money at an issue without actually resolving the problem. When I told a mechanic friend of the problems that I was having, and what I had done to try and fix it, he suggested performing a compression test, leak down test, etc, to find the root cause of the problem.

 

With a cylinder mis-fire code the first thing I would do is a "dollar-bill" test to check the valves.

Perhaps a techie can chime in but I am thinking the sensor is checking for the stress on the crank during a detonation cycle. If the valves are good and there is no spark there would still be compression/stress. No compression, the rod is freewheeling that would be basically no stress.

 

I had a similar problem 4 months ago. Turns out my fuel injector lines popped out slightly. Plugged it back in and the car ran fine

 

[QUOTE=MattB09;4321264]Have a R53 getting a P0301 cylinder 1 misfire code.

Little backstory, replaced spark plugs and wires a few months ago and had zero issues. Took it in to dealer about a month ago for other reasons and they said I needed to replace the valve cover gasket and spark plug seals. I did that and still no issues.

A couple weeks after that this started occurring. It went away a couple times for like a day but then came back.

Tried swapping spark plug and also wire to different cylinder to see if they would be the culprit and it still comes back P0301 cylinder 1 misfire. Doesn't look like a lot of oil or anything got down in there. I'm a basic mechanic so not sure what else it would be? Any suggestions what else to look at? Could it be the fuel injector? I have no clue about them.[/th

 

Hey there...what exactly did you do? I am having infrequent hesitation issues at around 2000RPM and I get the same code read. I was going to change out the plugs and saw your post. A little lost under the hood, though.Could you send a pic of what you did, maybe?