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Discussion Starter #1
Was driving to a destination about 3 miles away. 2 miles into it, the limp mode kicked in (lights, reduced power warning, emissions warning, etc) and a giant puff of blue smoke came out of the tailpipe.
I let the car roll to my destination all down hill.
Parked. went and did my business.
10 minutes later tried to start it but all it does is attempt to roll the starter and I hear a loud clunk but the engine doesn't turn at all.

I towed it to my mechanic but I don't have high hopes. Car only had 75K miles. Full service a year ago. New rod bearings at 60K miles.
 

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Wow! Sorry to hear about your situation. Please keep us updated on the autopsy.
 

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Discussion Starter #3
Thx, to make it worse, the IDrive said 'You can keep driving'.... I guess it lied to me :(
 

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WOW! So sorry to hear!! I hope you can determine the root cause and it can be repaired. Fingers crossed!!


Sent from my iPhone using Tapatalk
 

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So maybe some good news. My mechanic said that once he took out the spark plugs he was able to turn the engine by hand and a lot of fuel came out of the spark plug holes in bank 2 cylinders 8/9. He thinks injector failure caused those 2 cylinders to flood and seize the motor by not allowing it to compress. He did find fuel in the oil, not sure how that would happen. He suggests to replace all injectors on bank 2 and flush/replace the oil. He did say he felt resistance while turning the engine by hand but he is attributing that to the SMG clutch (although I left the car in 'N', I always do precisely for situations like this). I was doing no more than 4000 rpm when this happened. You think the engine is ok and worth attempting to save it?
Also, he said he saw a code for failure to communicate with the alternator.
 

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what year is your car? Fuel filter change history??? I'd make sure you save those injectors and have them tested you can run a can of brake cleaner through the inlet port and if it shoots or dribbles out, that helps show you have a leaky injector...
 

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Discussion Starter #8
Car is an 08. Had fuel filter changed exactly a year ago. What other reason would there be for a cylinder full of fuel other than a leaky injector? Maybe a non-firing spark plug?
 

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Car is an 08. Had fuel filter changed exactly a year ago. What other reason would there be for a cylinder full of fuel other than a leaky injector? Maybe a non-firing spark plug?
To my horror I discovered mine had the same fuel filter at 91k. Right now at 95k I have what I hope is a throttle actuator issue (from the symptoms and codes I've seen on the board). Im replacing all injectors, as a PM. The old ones looked pretty clean. Going to have them cleaned and flow matched to keep as a spare set..

20200413_195022.jpg
 

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So maybe some good news. My mechanic said that once he took out the spark plugs he was able to turn the engine by hand and a lot of fuel came out of the spark plug holes in bank 2 cylinders 8/9. He thinks injector failure caused those 2 cylinders to flood and seize the motor by not allowing it to compress. He did find fuel in the oil, not sure how that would happen. He suggests to replace all injectors on bank 2 and flush/replace the oil. He did say he felt resistance while turning the engine by hand but he is attributing that to the SMG clutch (although I left the car in 'N', I always do precisely for situations like this). I was doing no more than 4000 rpm when this happened. You think the engine is ok and worth attempting to save it?
Also, he said he saw a code for failure to communicate with the alternator.
Hello 335xi,

Please keep posting and sending pics.

Very interested in solution.

Mr. P
 

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Definitely a stuck injector. I've been reluctant to believe injectors themselves are at fault as they just rarely fail open in any other engine. Plus they're made by bosch who basically are responsible for mass produced fuel injection systems since the 80s. So the faulty fuel filter with integrated regulator theory makes sense. If memory is right Jim's failed engine had more than one fail right after each other. What are the odds of more than 1 failing at the same time? But in your case with a 1yr old filter this shouldn't have happened. Perhaps there's a reason why spareto is able to sell them for $10 a piece.
 

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Non firing plug cannot cause a cylinder to fill up with fuel. The injected amount of fuel is miniscule. The injector is commanded to open for a few milliseconds and based on the known fuel pressure, the pcm knows precisely how long to open the injector to let on the right amount of fuel based on how much air is in the cylinder. Most of the unburnt fuel and air (that is not combusted due to no spark) will simply exit on the exhaust stroke.

You may very well have the “injector lock” issue where it is locked open and thus bleeding fuel in the cylinder constantly. I’d say you MUST get them tested, mainly for piece of mind and true root cause analysis.

There is a very quick way you can tell if your fuel filter is original. When you pull up the rear seat and remove the circular cover on the driver’s side, you will see the ring on the tank and a white sticker with a blue K on it. That is basically a tamper seal from the factory. So if you see it and it looks undistirbed, you have the original fuel filter in place. It’s sad to hear that you already did that 1 yr ago and still had this happen!
 

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You should check out @P-Chi ’s thread on his 2 damaged engines he bought. Seems to be what happened to his. You should have the mechanic borescope and look for cylinder wall damage. If none is apparent, have him do a compression test also. If those 2 cylinder check out like the other 8, you may have escaped any damage with bent rods. Given you said you tried to start it later and it didn’t and heard a clunk, you may have bent the rods and scored those cylinders because you unwittingly started the engine with 2 hydrolocked cylinders. When you were coasting was it in gear or did it pop to N? If it was in gear the engine would have still been turning and expelling out air and fuel (safely). It’s after you stopped, where the cylinders are then able to fill up. Then when you start it, BANG!
Sorry, I hope everything is ok, but just explaining what could have happened based on what you wrote.
 

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Non firing plug cannot cause a cylinder to fill up with fuel. The injected amount of fuel is miniscule. The injector is commanded to open for a few milliseconds and based on the known fuel pressure, the pcm knows precisely how long to open the injector to let on the right amount of fuel based on how much air is in the cylinder. Most of the unburnt fuel and air (that is not combusted due to no spark) will simply exit on the exhaust stroke.

You may very well have the “injector lock” issue where it is locked open and thus bleeding fuel in the cylinder constantly. I’d say you MUST get them tested, mainly for piece of mind and true root cause analysis.

There is a very quick way you can tell if your fuel filter is original. When you pull up the rear seat and remove the circular cover on the driver’s side, you will see the ring on the tank and a white sticker with a blue K on it. That is basically a tamper seal from the factory. So if you see it and it looks undistirbed, you have the original fuel filter in place. It’s sad to hear that you already did that 1 yr ago and still had this happen!
All:
I am still struggling with injector issue on a running engine. As gmtegear posted, the amount of fuel per combustion cycle should be expelled through the exhaust. It takes a LOT of fuel to hydro-lock a running engine. If fuel injector was FULL open when running......maybe.....still should be expelled through exhaust and trigger MIL.

My thoughts. I am also still researching failures. Any all theories welcome.

I will wait for more information on this issue, but "blue puff" makes be concerned.

Mr. P
 

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Hmmmmm....head gasket failure. Park car for 10m. Coolant leaks to cylinders?

Big questions is "big blue puff"......grrrr!

Do not yet have enough experience with the S85 to say for certain, but the head-block-gasket apear to be very robust...unless overheated previously?

Looking forward to final results of what actually happened.


Mr. P
 

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Discussion Starter #17
Non firing plug cannot cause a cylinder to fill up with fuel. The injected amount of fuel is miniscule. The injector is commanded to open for a few milliseconds and based on the known fuel pressure, the pcm knows precisely how long to open the injector to let on the right amount of fuel based on how much air is in the cylinder. Most of the unburnt fuel and air (that is not combusted due to no spark) will simply exit on the exhaust stroke.

You may very well have the “injector lock” issue where it is locked open and thus bleeding fuel in the cylinder constantly. I’d say you MUST get them tested, mainly for piece of mind and true root cause analysis.

There is a very quick way you can tell if your fuel filter is original. When you pull up the rear seat and remove the circular cover on the driver’s side, you will see the ring on the tank and a white sticker with a blue K on it. That is basically a tamper seal from the factory. So if you see it and it looks undistirbed, you have the original fuel filter in place. It’s sad to hear that you already did that 1 yr ago and still had this happen!
I am 100% certain the fuel filter was changed. I received the old one back plus I trust my mechanic 100%. It was replaced as 'preventative' maintenance a year ago. How can the fuel filter cause the cylinders to fill up?
 

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Discussion Starter #18
Definitely a stuck injector. I've been reluctant to believe injectors themselves are at fault as they just rarely fail open in any other engine. Plus they're made by bosch who basically are responsible for mass produced fuel injection systems since the 80s. So the faulty fuel filter with integrated regulator theory makes sense. If memory is right Jim's failed engine had more than one fail right after each other. What are the odds of more than 1 failing at the same time? But in your case with a 1yr old filter this shouldn't have happened. Perhaps there's a reason why spareto is able to sell them for $10 a piece.
They are 32 Euro right now :)
 

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Discussion Starter #19
Definitely a stuck injector. I've been reluctant to believe injectors themselves are at fault as they just rarely fail open in any other engine. Plus they're made by bosch who basically are responsible for mass produced fuel injection systems since the 80s. So the faulty fuel filter with integrated regulator theory makes sense. If memory is right Jim's failed engine had more than one fail right after each other. What are the odds of more than 1 failing at the same time? But in your case with a 1yr old filter this shouldn't have happened. Perhaps there's a reason why spareto is able to sell them for $10 a piece.
A buddy of mine who has 2 N54 powered cars, on one of his N54 engines he had 2 injectors fail simultaneously.
 

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Discussion Starter #20 (Edited)
You should check out @P-Chi ’s thread on his 2 damaged engines he bought. Seems to be what happened to his. You should have the mechanic borescope and look for cylinder wall damage. If none is apparent, have him do a compression test also. If those 2 cylinder check out like the other 8, you may have escaped any damage with bent rods. Given you said you tried to start it later and it didn’t and heard a clunk, you may have bent the rods and scored those cylinders because you unwittingly started the engine with 2 hydrolocked cylinders. When you were coasting was it in gear or did it pop to N? If it was in gear the engine would have still been turning and expelling out air and fuel (safely). It’s after you stopped, where the cylinders are then able to fill up. Then when you start it, BANG!
Sorry, I hope everything is ok, but just explaining what could have happened based on what you wrote.
I was coasting in a high gear keeping the rpm low like 2K for the last mile precisely to avoid further damage. Tried to start it, like 6 times total. Only the 1st time it turned slightly and stopped. The other times it did not move much, it just clunked.
 
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