[JonEQuest]

I need some advice ASAP PLEASE!

This is my starting point: This is a 2007 335i salvage title wrecked project car I bought at auction and not registered yet. I have no history on this car but it has 75,xxx miles. I have not driven this car more than 10 few miles in the 2 months I have owned it, but it has idled for hours in my driveway while flushing dirty oil, etc. I have pulled the plugs and they are normal looking for an engine of this age. It runs decent but has a constant tick. One error code that keeps coming back is "Misfire on Cylinder #3", probably where the bad lifter is, right??

I am now in the process of replacing all 24 lifters. I have the cams, bearing ledges etc. out. I am cleaning everything after previously doing 3 oil changes and engine flushing with MMM and Rislone. Yesterday I found what is POSSIBLY a small strip of an old serpentine belt that got sucked in at some point. I found it at the top left (exhaust) VANOS/chain tensioner area just sitting there, it was not stuck on anything and lifted right out. The belt that came with the car was intact when I replaced it with all the pulleys. But maybe this is a piece of an old one or it could be something else?

OK, now to the point. I noticed that of the 7 oil drain holes on the exhaust side of the head at the lowest point there are 2 that do not drain oil at all. I used a syringe to see where oil goes and the other ones let oil travel between the area above where the black torx head bolt is and the drain holes I am referring to, and of course somewhere below they drain oil down into the engine. Starting from the front Holes #1 and #4 only allow oil to pass between the head bolt and the drain hole but the oil that is in there never drains away. I think I found a smoking gun. Obviously these drain holes need to drain oil as well. Also hole #4 drains the oil from one lifter of cylinder #3, the one that gets misfire errors. Sounds like cause and effect to me. Now what to do to clean this obstruction? Part of me wants to squirt carb or brake cleaner in there and flush it through BUT I don't know where this hole goes. If it goes straight to the pan no problem as I am draining all oil before and pouring some fresh "flushing" oil down the holes before putting the valve cover on anyway. Then I will put the plug back and fill the oil.
Yes, I know the best thing to do is pull the oil pan. But It looks like that is a serious job and I plan to use my endoscope to look in the oil pan through the drain hole for any other rubber bits instead. If I find any illegal aliens that I cannot fish out then I will pull the pan, but I am REALLY trying to avoid that. So where do these holes go? How narrow do they get? I just don't want to flush carb cleaner or something down the holes and find out later these holes go straight to the crank bearing or something.

[JonEQuest]

Bump

[robthewrench]

I'm not sure about the lifter being the mis fire issue. Unlike most other cars, the N54 has a very unique injector / coil setup and this is usually the cause of mis fires. Did you already replace coils and injectors?

I don't believe a clogged drain hole could lead to a mis fire. As to your concern about it leading to a bearing, no drain hole ever leads to a pressurized crank bearing. All crank main bearings receive oil from the pressurized oil pump circuit.

[JonEQuest]

Originally Posted by robthewrench

I'm not sure about the lifter being the mis fire issue. Unlike most other cars, the N54 has a very unique injector / coil setup and this is usually the cause of mis fires. Did you already replace coils and injectors?

I don't believe a clogged drain hole could lead to a mis fire. As to your concern about it leading to a bearing, no drain hole ever leads to a pressurized crank bearing. All crank main bearings receive oil from the pressurized oil pump circuit.

thanks for the advice. I I guess I didn't think about the fact that it's always going to be pressurized oil going to crank bearings. in any case the two areas I was referring to or actually not supposed to drain oil at all. I had to get a better angles and better light to see that. no I have not replace the coils or injectors yet. I did move a coilover. I am also installing new spark plugs since the current ones look original. if the problem doesn't go away with new lifters I probably will try swapping injectors and see if it follows. I didn't think the oil drain would cause a misfire. I think he was just a lifter is not working correctly then the valves are not opening and closing correctly we can cause Blow by and improper firing.

[Supra2k6]

injector tick is normal no these cars, that being said it's most likely a coil for the misfire. If one of the plugs smell like gas you might have a leaky injector.

there is two reasons for the tick one injector noise which is normal on all n54's. The other one all pre lci cars had a bad design on the head which lead to low oil pressure at low rpms that was harmless. there is a TSB for this with a few cheap solutions and if the customer kept complaining the head was replaced by BMW.

if the Belt snaps it gets sucked in thru the front main and clogs up the oil pick and some gets caught on the chain. This can be cathrastophic scored ledged, etc but some people get lucky after the clean up and the car is fine for regular driving.

[JonEQuest]

Originally Posted by Supra2k6

injector tick is normal no these cars, that being said it's most likely a coil for the misfire. If one of the plugs smell like gas you might have a leaky injector.

there is two reasons for the tick one injector noise which is normal on all n54's. The other one all pre lci cars had a bad design on the head which lead to low oil pressure at low rpms that was harmless. there is a TSB for this with a few cheap solutions and if the customer kept complaining the head was replaced by BMW.

if the Belt snaps it gets sucked in thru the front main and clogs up the oil pick and some gets caught on the chain. This can be cathrastophic scored ledged, etc but some people get lucky after the clean up and the car is fine for regular driving.

I heard about those things that you mention. This was definitely more than just normal engine noise. It was a distinctive tap that went with the speed of the engine. That's why I'm doing the lifters before troubleshooting further on the occasional misfire.

[JonEQuest]

OK, I put everything back together and I still have a noticeable tapping rattling sound that goes with the speed of the engine and seems to be a little worse as the engine drops RPM from about 2,000 RPM. Could it just be the timing chain tensioner?