Have you eliminate the possibility of coolant leaked into #4? How stable is the coolant level in the tank? Remove #4 plug with cold engine in morning and look for dews on its tip?

 

Sapote I'm off work tomorrow so I will be doing both of these tests in the morning. Thanks!

 

I know I’m not supposed to post screenshots looking for help but this is all the time I have right now. CEL came back today, cylinder 4 misfire. I felt absolutely zero shake this morning and I would say it’s running better than ever, no long crank. https://imgur.com/gallery/UK21Z4P what could this mean? Specifically fuel trims and calculated load. Is MAF reading normal for 700rpm idle?

 

31.2g/s is quite a lot

 

So should I purchase a new MAF? This was freeze frame immediately after the CEL came on. The car was not fully warmed up yet. Should I be looking into O2 sensors as jfoj mentioned earlier? Why cylinder 4 every time?

Also going to look into this thread by jfoj regarding brake booster vacuum leaks that usually wont show up on a smoke test. https://forum.e46fanatics.com/showthread.php?t=1057387

 

This morning's misfire was especially rough. It would not stop until I turned off the car and started it again, misfire completely gone and did not return. wtf??

 

So I waited until the engine was cold and I cranked it over for about one second, then turned it off. I Pulled spark plug in cylinder 4 and it was completely saturated in a liquid that had the consistency of water and smelled like exhaust fumes. I also pulled cylinder 2 and it was completely dry except for some moisture inside the threads.

 

So yesterday I had it smoke checked again and they found the actual DISA unit was cracked, not just the o-ring and seal. So I replaced the DISA with a used unit, assuming it works. I ran a diagnostic report this morning. https://www.dropbox.com/s/rwi8ge4ygxz1f3j/Diagnostic Report 2018-10-27.html?dl=0

 

Hey guys. So I have replaced the MAF with a brand new Siemens VDO unit and I cleared the codes. I'm waiting to see if the lean codes come back but the fuel trims did seem to improve a bit. In regards to the misfire I still have a misfire and cylinder 4. As mentioned above it seems the plugs are getting saturated prior to ignition and are fouling. Any advice is appreciated.

Here are logs from yesterday, immediately after installing MAF (CEL still present) https://www.dropbox.com/s/ty4rsipjmkby6kp/CSVLog_20181101_154957.csv?dl=0

 

If you are starting the engine and not allowing it to run at least 3-5 minutes and/or driving it around the block, this is a clear way to end up with misfiring on the next engine start.

Do not start the car and move it from the driveway a few car lengths into the garage. This will cause problems every time.

If the problems only occur after the car has sat overnight, you need to perform the smoke test when the car has sat overnight as well. Even a short running period can allow things to expand and air leaks to be sealed up.

Suggest you drive the car for a fuel tank of fuel and under different conditions to see what happens. You may have an engine mechanical problem, but the obvious problems needs to be sorted out as well.

 

No I don't do that. I'm starting to lean towards a bad exhaust manifold gasket that expands when the engine warms up. Still doesn't explain one plug being wet and the others are not.

 

You have coolant in that cylinder -- bad gasket or cracked head. This is final.
This is a perfect case: misfire when cold due to coolant inside, but the leak was fixed when the engine was warm due to metal expansion. This is why I had asked before about coolant level stability. Time to pull the head.

 

Yeah as I described in a previous post it smelled like gasoline / exhaust fumes. Certainly not sweet like coolant. But we will find out soon enough with a cool engine compression and leak down tests

 

@jfoj you are amazingly patient! Years of you responses being ignored and you keep on trying. It is appreciated by some of us thank you!

I don***8217;t think you mention it enough in your vacuum leak master thread, but the plastic valve covers get pretty brittle after 10-15 years and start developing cracks, especially after a gasket change adds more stress. Thes cracks, as you well know and preach, can be at least part of the cause of misfires on seemingly random cylinders.

About a month ago I was forced to buy a real BMW valve cover ($400, ouch!) after JB welding a couple small cracks around the middle bolt holes. I was ready to reinstall when I held it up to the sun to admire my patch work and it slipped from my oily hands and shattered. Best thing that could have happened though...right when you touch a brand new cover you can feel how ***8220;soft***8221; (not brittle) it is, and the genuine gasket that comes with it works better than any aftermarket gasket I***8217;ve tried. Incrementally tightening the bolts cinches them until they bottom out and the gasket squishes perfectly to fill its slot in the cover and mate the head surface.

Sorry for careening a bit offtopic OP, but definitely check everywhere for vacuum leaks and continue on to more advance tests before assuming it***8217;s catastrophic...it***8217;s amazing how a small leak in just the right spot can cause a seemingly unrelated misfire

 

Is there any method for testing center valve cover gasket rings for leaks?

 

This is the easier test to be done before testing the valve cover: drive the car to normal temperature -- with no code or reseted and no code shown thereafter -- then park it overnight. Next morning remove #4 plug and look for wetness on plug tip. install plug, crank the engine 1 sec then shut off. remove and look at # plug again. If there is any sight of wetness then coolant got in.

 

Probably the easiest and simplest way to narrow things down is the following:

Drive the car until the engine is fully warmed up, bring it back and park the car.

Pop the hood, open up the DME box and pull out the fuse carrier that has the 5 fuses in it. Shut the hood and allow the car to sit over night.

In the morning try to start the engine, it should not start with the fuse carrier removed because this should provide power to the fuel injectors, with this fuse carrier removed the fuel injectors should not spray fuel in the engine. Would try to start the engine 2-3 times, then pull the problem spark plug and see if it is wet, would also pull the adjacent spark plugs and compare.

One warning as I am not there to see what is going on. If you have the cabin air filter out of the car when the car sits, if it rains, it is easy for the rear most plugs to get water in the spark plug wells. Always cover the engine with plastic if the car is not garaged while the cabin air filter housing is out or place the cabin air filter housing back in place to protect the rear most part of the engine.

 

Don't see any moisture but it looks like there is a little bit of oil pooled ontop of the crush washer on the spark plug in cylinder 1. All other cylinder walls look clean but 1 has some staining. Note I still have misfire in cylinder 4. Seems to be getting worse. Any correlation here?

 

All other cylinder walls look clean but 1 has some staining.

How did you see the cylinder wall still with head installed? And what about the previous report of seeing #4 plug saturated with liquid having the consistency of water, and now all dry?

 

Did you perform a compression and/or cylinder leakage test and if so, what were the numbers associated with the test?

Have you swapped the #4 spark plug to a different position?

Have you checked the power brake booster for leakage?

 

I'm taking it to my mechanic next Wednesday since I can't find the proper tools needed for a compression and leakage test. Will report back with those results.
I have swapped spark plug, coil and injector from 4 to cylinder 1, p0304 still present.
I have not had any symptoms of a failing power break booster but I suppose I will check that in the meantime.
I noticed in another thread you mentioned you should not be able to blow through the fuel pressure regulator vacuum line. Can you elaborate on this? I'm still suspecting fuel delivery issues and I am able to blow through this line. No cracks in the line.

 

Cylinder 1 200psi
Cylinder 2 200
Cylinder 3 195
Cylinder 4 240
Cylinder 5 200
Cylinder 6 210

Sent from my SM-N950U using E46Fanatics mobile app

 

Is 240 psi for #4 correct?

Seems high and a large variation from the other numbers.

 

Yes. We looked inside and there is a pool of coolant on top of the piston. RIP. Thank you everyone for your help with this.
By the way, coolant does a fantastic job of breaking down carbon deposits. Just thought I should share that bit of information. [emoji2]

Sent from my SM-N950U using E46Fanatics mobile app

 

If you are gambling man, you can try some additive in the cooling system, cheaper that having to tear the engine apart. I know there are many here that will whine and complain how all sorts of bad things will happen about clogging the radiator or heater core, but it won't. For $10 or less or having to pull a head and deal with the down time, I know what I would do. I mean these cars are getting old and how much time and money do you want to sink into a 13+ year old car?

I would start with this and see what happens - https://www.amazon.com/Genuine-GM-1.../B000QIH3C4/ref=sr_1_2?ie=UTF8&qid=1541847324&sr=8-2&keywords=GM+stop+leak+tabs

So you may laugh or question this, but GM uses this as a factory additive on many cars. It is actually ground ginger root. The stuff works, I would try this first and see what happens because your leak is very small at this point. If no luck you could move on to something more industrial like Blue Devil. But I would consider the ground ginger route and see what happens.

Again, it will not clog anything up in the cooling system. I have seen radiators and heater cores that this was used on, most successfully, some not due to all the flexing and the problem with things like plastic end tanks that crack continue to crack and while the ginger root can close up some of the cracks, as they grow, nothing can stop the flexing of the plastic end tanks. I have cut some of these open for inspection and there is no buildup in the heater core or radiator.

If you try it and is solves the problem, it will be the best $10 you have ever spent and you will thank me. If you try it and it does not work you will still thank me because you can move on to something more industrial that will probably solve the problem.

Let the whining and the hate begin!!! I know what I would do and have done in the past with success.

Your move.

 

Thank you, I will try it. Any chance its something other than the head gasket or crack in the head? There is no bubbling in coolant, no milk in radiator or under oil cap. Also no steam from exhaust.

Sent from my SM-N950U using E46Fanatics mobile app

 

If the car was never overheated, I suspect the head gasket was damaged and it may just require a new head gasket.

 

You were right. Thanks again. Hopefully this offers some insight for others with this issue. Single cylinder misfire and long cranks, check compression first and if you have a boroscope even better. Time to move on.

Sent from my SM-N950U using E46Fanatics mobile app