I will try to give all the history so y'all can make a good assessment.

The timing chain was replaced last summer by a reputable shop that works on Beemer and Mini's. Not many miles were put on it after that. The young owner said she had some more codes (some time after the timing chain replace) and she didn't want to put any more money in the car. It sat at their house for sale for 9 months. Driving by it so often I had the crazy notion to buy it and do the 100K service and give it to my grand daughter.



I took it and had the code read and it was something to do with the PCV. It was smoking a little which explains the need for replacing the PCV membrane. After replacement, it still had a little rough idle but no codes. I suspected a vacuum leak and what better place to start than replacing the vacuum hose that is made of ribbed plastic, coming off the intake manifold. Interesting job to replace, no biggie.



I replaced the water pump, plugs and ignition coils. I went ahead and replaced the cam timing sensors and the Vanos solenoids (?) intake and exhaust. I changed the fuel filter and there was only a few gallons of gas in it so I added treatment and filled the tank with regular unleaded the first time I drove it. I meant to add mid-grade (89 octane) fuel, but forgot. I did add another Techroline additive.

It started to have coolant drip on water pipe behind the water pump. I replaced the water pipe with a hillbilly brand and it kept dripping, even with new O-ring at thermostat housing (TH). I bought the name brand and installed it with new TH, which I bought from Prime. Well, I didn't have any leaks but the coolant temp sensor went out in a week and the other sensor failed. So, I bought name brand and no further issues with coolant.



To the point- I started to get a knock sensor engine code for the ECU. I replaced the knock sensor out of stupidity before digging deeper to see if it was a misfire. Looking at the ECU with the code reader I saw that it was having misfire on the #1 and #3 cylinders, intermittently at low rpm's. Made me think it was because of the ignition coils I bought from Prime. I replaced them with Bosch and drove it a few miles. For the first ten mile trip, I didn't get any knock sensor messages. My grand daughter came over and after "surprise" I took her for a drive she only has temp driving permit. With her driving I was watching the ECU, live system data, for the cylinder firing. I noticed a misfire on #1. Just once and then again after we stopped. The second misfire set off the Knock sensor ECU engine warning. I pulled the plugs and they were a little dirty. But I believe that was caused when I replaced the PCV, as I started the engine with the membrane askew and it blew soot everywhere. Yikes.



The plugs were the NGK iridium (recommended for this engine) set at .032" or .080 mm. I keep test driving the car (short 5 mile trips) to see if things clear up. Not so, still getting misfires on different cylinders and in turn the knock sensor ECU error. The car drives good and I don't think I can feel the misfire when it happens. The hand held reader only shows misfire once between long intervals, those usually at slower driving



I don't know what to look at. Unless it still has to do with the fuel, I am at a loss where to go next. Any suggestions would be appreciateed.

 

These are the NGK recommended plugs for an '07 N12 manual trans --- https://www.ngk.com/ngk-97968-ilzkbr...ium-spark-plug Note the gap of 0.032" converts to 0.8mm --- you're off by an order of magnitude. Hopefully a typo, not the setting you used. And, FYI, the "8" in their part number "ilzkbr7b8g" translates to 0.8mm --- the "7" is the heat range. "97968" is their stock number.

These engines want at least 91 octane, so using 89 could be the source of your misfires. Rather than wait til the tank runs low to refill with 91, consider buying a 5 gal can of 100 or so octane (unleaded) from your local auto parts store and mixing it with the 89 still in there. Might take a few miles to get the mix thru the lines and to the injectors, but it'll let you know for sure if the low octane was your problem. Personal opinion --- additives like Techroline are causes, not solutions.

Pretty sure the high octane won't hurt the engine --- I've added 5 gals of 110 octane to about 1.5 gals of 91 and run with water / methanol injection at track performance with no adverse consequences --- awesome results. But, as you can see from my signature, my engine is built for it. Yes, the high octane gas is pricey, but it's only a 1-time use and should provide an answer.

Keep us posted ---

 

Yeah, I missed a digit on the plug gap. However, I was not aware that the base model non-turbo) required premium. Okay, well that explains a lot why at low rpm's I have a little misfire.

Thank for your help. I'll get some gas out of there and add octane. I work in a refinery and we always say "the solution is dilution." In this case diluting the low octane with the higher.

 

Suggest you check the compression and if you have access to a leak down tester, check the leak rate (however the leak down is pointless if you a cylinder with really low compression)

 

It has nothing to do with cylinder compression. The misfire is too erratic and at real low rpms. I'm waiting for the ambient temp sensor to rule out an occasional coolant Map sensor alarm that goes off when it warms up. I think it goes off when the thermostat opens. It goes into limp mode. I believe it's because the ambient temp is seeing 32F and it mucks something up. I don't even know if the ambient has something to do with the slight misfire. It varies on which cylinder. I really can't feel it in the engine. Only see it on the live stream and the 2nd time it does it the knock sensor goes off. Trying to solve one problem and then will try for the misfire issue. I can't get it to misfire when I start it up and let it idle. It only does it when I take off down the street. It's not like I can look at it with multi meter either. This is the most puzzled I've ever been working on an engine.I have on loads of them too........ just sayin

 

You're certain of this? I'm with farside on his suggestion of a compression test. I'd want to know I'm starting out with a healthy long block before throwing a bunch more time/money/parts at it.

 

I have the stuff to do a compression test or leak down. The latter, I"ll have to look up. Never heard of this (before seeing on this site) and assume it looks at the intake/exhaust valve conditions as well. I'll fall over dead if a 100K mile engine blows a compression test. No offense but even GM makes motors that get past 200K before rebuilding. Everything else on those cars fall apart but all manufacturers build engines to last well over a 100K. Especially when BMW uses synthetic oil, which I have used exclusively since mid 80's. Mobil 1 introduced a clip where they fried french fries in their motor oil. Cooking at 350 F is probably not that big of a deal, but it impacted my thinking. I have used it in all my vehicles and changed oil at the 10K interval since that time. Gulf Oil corporation forbad the changing of oil in their carpool vehicles. They only changed the oil filter and added oil. They tore all vehicles down at 100K miles to see how each oil performed. They preached that their oil doesn't break down, but does get dirty.That supported my 10K oil change interval. Just sharing info. I must be close though, doesn't BMW recommend 15K change intervals? That still means keeping a good oil level. Low oil level is a killer

 

Far as I know, the N12 is also direct injection (like my N14). If the intake valves haven't been walnut blasted in awhile, they might be caked-up enough to cause low compression. I completely agree about mfg'r's 100K minimum life expectancy, but in the case of Mini's R56, it's the exception to the rule. There are so many different "new" features from the Gen 1 series, that one of them is bound to fail, specifically timing chain tensioner and HPFP.

As for your 10K oil change interval, it's highly recommended you change it at 5K maximum, sooner is better. Contamination is fierce due to valve stem seal failure and a questionable PCV system. Worse for the N14's due to piston blow-by / ring failure. Yes, BMW originally recommended a 15K oil change interval for the R56. However, most dealers are now recommending 10K and Mini indies recommend at least 5K. But, like break-in procedures, recommendations vary.

Been over a week now, have you raised the octane in your tank yet, and run it enough to get it thru the lines?

 

Yes I was able to bring up to +92 per the chart. Was only able to drive it less than 20 miles cause I keep getting this Coolant Map sensor alarm. I believe the alarm goes off when the coolant thermostat opens and it has something to do with ambient air sensor reading. I noticed that live stream is showing 32 degrees for ambient air. That coolant MAP alarm causes limp mode, which I can clear with the reader, but I have a new one coming by Tuesday, don't mind the delay. Then I'm gonna get in it and drive up the road to Beaumont and back, a hundred highway miles round trip. The engine should love that. We are still having a mild spring for near June. I will certainly let you know.

 

"Coolant MAP sensor"? I don't recognize this description. Can you locate it on this illustrated parts diagram --- https://www.realoem.com/bmw/enUS/select I see a "Differential Pressure Sensor" on the intake manifold --- probably measuring difference between ambient and manifold pressure. This is probably what makes the engine perform normally at high elevations. Is this the part you're referencing and replacing, or maybe the t'stat temp sensor?

"MAP" means "Manifold Atmospheric Pressure" --- pressure, not temp, and I can't think of any sensor where coolant pressure is measured. The N14 will throw a code if coolant isn't up to a certain temp within a given time. I had this after a tune where operating temp was lowered to 175F --- tuner forgot to override the fault. But this is all for coolant temp, not air temp. Ambient air of 32F shouldn't cause grief --- that's just normal winter driving in some places.

I can't comment on N12 but the N14 has two air temp sensors --- one for ambient and one for air between the intercooler and throttle body. N12 shouldn't need a 2nd sensor for temp --- no FMIC (I think).

 

Oldbrokenwind, I need one question answered. The shop that did the timing chain (previous owner) left off the exhaust heat shield. At first I was thinking this was laziness. Now you folks have brought to my attention the exhaust valves and carbon build up. I don't have an knowledge about the intake and exhaust valve design.
Was the heat shield left off on purpose for heat dissipation?

Advice from anyone would be helpful.

Regards,
BC

 

Missing shield sounds like a combo of sloppy/lazy.

Carbon build up is an issue on the intake, not exhaust side.

Some carbon deposit on the exhaust valves is normal.

 

Thanks for that info on the heat shield. I figured it was sloppy or oversize, by the shop. As for answering question about MAP sensor... I would get an alarm that read MAP temp error. Or something to that effect. This is the same alarm that you get when thermostat housing built in sensor is going out. I replaced the housing and every time I drive the car 10 miles the alarm shows on the reader. It goes away, but I believe it shows up due to ambient air temp sensor was broken. I have replaced it, but am waiting on a 3 pc heater hose that I'll get Monday. Monday night I should know, will share then.

 

It turns out the 2F07 Map thermostat mechanism code I'm getting is related to the car engine temp and thermostat opening timing. As soon as engine reaches 105 I see (watching live stream with hand held code reader) the temp dropping to normal 85-90. However, everytime it reaches that magic 105 it causes the alarm to go off. That means means limp mode as soon as I slow down. I've ordered a new OME (Mini) housing. I am a world expert at changing out the housing now, as this will be 4th time.

 

I just wanted to update this thread. My knock sensor issue was the wiring from the ECU to the sensor. I ran an external wire and it ran perfectly. Wow, what a pain in the butt getting to that point. Should have tried this much sooner. Running off Pin 33 and 34 in the ECU to a new sensor connector and my wold is happy. I had a erroneous code for the exhaust cam shaft sensor but discovered it was the connector. All good right now. Wow. Amazing Thanks to so many with good info. I will say this to the many on this forum. The carbon build up on the intake is not apparent on the base models, non S. Just for your info. We don't have turbos or their oil leak to the intake. Just sayin..........