Engine Misfire?

garfield81 · #1 11-23-2013, 03:34 PM

Tried starting the X this morning and the engine died as soon as it started up. Tried starting again and the engine wouldn't start. Then I smell something burning. Run out open the hood and everything looked ok. Checked engine oil (as I had recently changed the valve cover gasket a few weeks ago) and engine oil was pretty close to Max.
Got back in the car after a little while of looking around in the engine and tried to crank it up again and after a long crank the engine picked up and I kept my foot on the gas to avoid the engine quitting out again.
Went on a short drive and everything seems ok. Killed the engine and restarted and the engine picked right up.

Hooked up a generic OBD scanner and got two codes. P0301 and P0303 which according to the scanner is a misfire on cylinder 1 and 3.

So three questions:
1.) Do these codes really mean misfire on 1 and 3 or do they mean something else on a BMW X5?
2.) Is this related to the valve cover gasket replacement job that I did and somehow messed up?
3.) What should l do now?

Thanks for your help

Edit: Forgot to mention that the car only has around 75K miles and I did not change the spark plugs when replacing the valve cover gasket.

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TerminatorX5 · #2 11-23-2013, 03:47 PM

hmmm... from your description, i would say fuel delivery at first... but then - something is burning... was it oil burning? plastic? electrical insulation?

but then, you got a long crank - these cars equipped with "auto-crank", meaning that they will crank automatically with only a brief key turn, until the DME gets "engine running" signal, assuming that other signals are within parameters, including the battery... surprisingly, a low voltage battery with high enough CCA can turn the engine (i found out on mine, a 10.5V battery, that is NOT supposed to start the engine, still started the engine on a long crank)...

the generic code reader is just that - generic code reader, that will just "wave" in the general vicinity of the problem... you need a BMW specific software to narrow the issue down... the misfire could be secondary - a computer could not start the engine due to some issues, in the process detected that the fuel mixture did not ignite, cut off the offending cylinders to avoid further damage to the cats... or, the misfire could be primary - a coil is shorting or the spark plug is shut...

how old are you plugs? were they ever changed? the coils? how good is your battery? has it let you down before? was it ever discharged and then recharged? what is the state of your fuel delivery system? that includes fuel filter, fuel pump, the fuel rail...

you see, without further narrowing down your issue with the software, those symptoms can be wide spread on the causes...

or, it can be just a glitch... lets see what others think...

garfield81 · #3 11-23-2013, 03:52 PM

Terminator,
Thanks for your reply.

I can only answer a couple of your questions
Battery: Had the battery discharge on me last year but that was due the DICE silverline pro not shutting down. Took the battery to Battery Plus and they tested and said the battery was good.
Plugs and coils are originals I believe and never replaced.
Fuel delivery system - No idea on how to check the state.

Also, I don't thing my X has the auto-crank feature.

TerminatorX5 · #4 11-23-2013, 04:16 PM

lets see what other folks would say about your issue... did you have any other problems meanwhile? can you test the battery once more, just to eliminate the battery from this equation?

oh, i think all E53s had the "automatic start" feature, and especially yours, at the last production year... it was not an option, it was part of the car's design... it is not a remote start, or a button start - all it is, when you crank the key, you do not have to hold the key in cranked position to continue the starter motor to crank, the electronics take over that "hold-key-in-cranked-position" feature... which was a pre-cursor to the push button start on the later models...

garfield81 · #5 11-23-2013, 04:28 PM

I tested the Voltage on the battery. With the car running I got 14.33 V and the car off I got 12.30V which seems like both alternator and battery are good.

I am also thinking of pulling out the coils on cylinder 1 and 3 to see if there is any oil on them causing a misfire. Will that be helpful?

Yes I know about the auto-crank feature your talking about as I have seen/experienced it on a 4.4 but I am pretty sure my 3.0 doesn't have it.

sunny5280 · #6 11-23-2013, 06:21 PM

Quote:

Originally Posted by garfield81

I tested the Voltage on the battery. With the car running I got 14.33 V and the car off I got 12.30V which seems like both alternator and battery are good.

I am also thinking of pulling out the coils on cylinder 1 and 3 to see if there is any oil on them causing a misfire. Will that be helpful?

Yes I know about the auto-crank feature your talking about as I have seen/experienced it on a 4.4 but I am pretty sure my 3.0 doesn't have it.

Swapping coils around is a way to test if the coils are causing the problem. If the misfires follow the coils there's a high probability the coils are the problem. I assume you meant plugs instead of coils as I wouldn't expect to see oil on coils.

upallnight · #7 11-23-2013, 06:25 PM

Oil leaking from the valve cover and collecting in the spark plugs holes are known cause of misfires.

garfield81 · #8 11-23-2013, 06:33 PM

So I pulled out all the coils (not the spark plugs) and all of them were dry (which sort of makes me happy that I didn't mess up the valve cover gasket replacement job).

Should I have also pulled out the plugs and checked for oil on them? I thought the only way oil got to the plugs from the valve cover was over the coils. Also when I did replace the valve cover gasket I noticed there was some oil on the 3rd (or maybe 4th) coil.

bcredliner · #9 11-23-2013, 06:37 PM

I don't think you have done near enough troubleshooting to start throwing parts at the problem, especially since at this juncture there is no problem.

Right now I would focus on the burning smell.

If it is connected to the valve cover gasket it would be a were that is shorting that could cause the burning smell.

Something burning--what did it smell like.? Rubber, plastic, coolant, burning oil etc.?

How long did you try to start the engine before you smelled something burning? If you cranked the engine over for a long time the smell could have been the starter or associated wiring, even coming from the battery cables.

Was there any indication where the smell was coming from?

Any smoke?

garfield81 · #10 11-23-2013, 06:42 PM

Quote:

Originally Posted by bcredliner

I don't think you have done near enough troubleshooting to start throwing parts at the problem, especially since at this juncture there is no problem.

Right now I would focus on the burning smell.

If it is connected to the valve cover gasket it would be a were that is shorting that could cause the burning smell.

Something burning--what did it smell like.? Rubber, plastic, coolant, burning oil etc.?

How long did you try to start the engine before you smelled something burning? If you cranked the engine over for a long time the smell could have been the starter or associated wiring, even coming from the battery cables.

Was there any indication where the smell was coming from?

Any smoke?

I have no idea where the smell came from and I would say it smelled like burning rubber. I opened the hood to look for any smoke and no smoke. Then I tried to start the car again and after a long crank it started but no burning smell or smoke this time.

To me it seems like a pulley or something was jammed and a belt heated up due to friction hence the burning smell. That probably also caused the engine not to turn and start. I am no mechanic but this is my theory.

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