Misfire Nightmare!

[that1blue92]

Error

[Scrippy]

So I am fighting 27B0 secondary air system bank 1 error myself. I've replaced both EGR valves and the suction hose but the error persists. I am going to swap my front O2's between bank 1 & 2 and see if I get bank 2 error now. If so I'll just replace both front O2's. That might be your issue and I would recommend swapping O2's to alleviate your 27B0 error. As far as your build up on some of the plugs, I would suggest you should replace the rubber rings on your plug tubes when you get the valve covers done. Also inspect the plug tubes for cracks as they are plastic. I think oil is leaking in and fouling your spark. This could contribute to the 27B0 as the combustion is probably low leading to bad sensor readings caused by incomplete combustion. Start off sorting your plug tubes though because that's a bigger issue that can damage the cylinder walls if too much oil gets in frequently. 27B0 won't damage the engine just mess up smog. Good luck and report back

[oolas3]

Originally Posted by m3reid

Punching the air over how much just O2 sensors are on these haha, can you think of any reason why cylinder 8 is the only cylinder that's thrown any kind of code if cylinder 1 is the problem? Going to pull all 8 plugs today to double check them.

You can buy a Bosch O2 sensors on Amazon for $75.

[Redd]

Try removing the entire intake system including the plenum and starting the car. Under normal conditions it should idle and drive smoothly without the plenum but will give a CEL relating to idle air control. If your car runs fine without the intake, possibly its an air leak somewhere.

I was also fighting misfire issues recently related to intake air leak (all cylinder misfire). Once I solved the leak, I found out that the prolonged misfiring had damaged the O2 sensors causing the engine to randomly hiccup/stumble under load. Replaced the O2's and solved that. Just fyi.

[Scrippy]

Originally Posted by m3reid

Punching the air over how much just O2 sensors are on these haha, can you think of any reason why cylinder 8 is the only cylinder that's thrown any kind of code if cylinder 1 is the problem? Going to pull all 8 plugs today to double check them.

The first thing that comes to mind are the plug tubes based off all the info you gave. Cylinder 8 is the back of the block where heat can build up. There shouldn't be any oil on the threads of a plug or inside the tubes. I mean if your doing the valve covers just buy new tubes for the leaky ones and get past all the doubt. I know money doesn't grow on trees but you don't want to remove the valve covers later for a $22 part.

[irokwrx]

I think this is the rear
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

And this is front(Before Cat)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Double-check front and rear part numbers, I just looked in my past orders

[rcracin]

how many miles on your car?

Could also be injector or clogged cat in addition to everything mentioned above. Lots of things to inspect or try changing, but bmw ista is your best bet to help pinpoint the issue. Try your local forum to find somebody who has it and willing to help.

[linnadawg]

Check your ground on the valve cover for the ignition coils. Mine was loose and only causing a cylinder 3 misfire even though it’s the ground for the entire bank of coils.

[///Mobbin]

Just wanted to mention that replacing the upstream O2 sensors worked wonders for my car (slightly different code set though) - LINK

[rcracin]

Sorry man.

Bore it out and build fresh

[spammysammich]

Originally Posted by m3reid

Update:
Replacing upstream o2 sensors (Bosche) and exhaust gasket solved the 27B0 “Secondary Air System Throughout Bank 1” but I still have 276E “Injection Valve Cyl 8 Electronic Diagnostic”

Ordering a new injector for cyl 8

Second update:
Was getting a contact vibration from the cats touching the heat shielding so I went to sort that out, tightened up the header to mid pipe bolts after letting run for a bit...secondary air injection bank 1 code is back along with cyl 8 injector code that's been outstanding. Maybe secondary air pump went out? Im not seeing any vacuum leak on my obd2 live reader though.

Also noticed a few drops of coolant on my oil pan skidplate, tracked it up top to either the fitting that leads from the head to the coolant reservoir or the fitting directly below it that goes into the block (caked up green coolant in that area)

sorry to hear about your engine problems. How long did you have the injector fault showing up?

[spammysammich]

Scary, good luck on the rebuild. try to stay positive.

[MR_X]

Do this before you replace the motor. Change the injector and take the spark plug out of that cylinder. Remove fuel pump fuse (#70 I think). Crank the engine to get the fuel out of the intake runner and cylinder. Change oil and filter. Put fuse back in. Pour a straw full of ATF in the cylinder. Put spark plug back in and crank it up. It is going to smoke and idle like crap. See if you can hold idle to at least 1k rpm’s and feel for vibrations and listen for odd noises. If you didn’t get any vibrations, go and DRIVE THE PISS OUT OF IT. Sometimes the piston rings need to expand back in place and will give low compression numbers. I got lucky 2 weeks ago when I had the same issue.

[Redd]

Jvictormp had the exact same problem. Cylinder #5 injector stuck open, hydrolocked. He thought he got away lucky, but 2 yrs and 7k kms later the rod snapped and blew a hole in the block.

https://www.m3post.com/forums/showthread.php?t=1851485


What's the mileage on your car? These injector stuck open stories seem to be popping up more regularly, even in the UK forums. I wonder if fuel quality has anything to do with it.

[MR_X]

Originally Posted by m3reid

Are you able to offer any further information? If it doesn't work the motor could throw a rod through the block, no?

If your rod is bent you will know it by vibrations and also the sound of a rod bearing. Unless you bent the hell out of it (and if you did you would have a hole by now), 58 psi for compression seems too low.