Misfire in the mornings

timx5 · #1 11-02-2009, 08:45 PM

Hey,

Wondering if anyone has any advise on my problem.

I have a 2005 X5, 4.4i. Only 67,000 kms on it. Not every morning, but most mornings when I start the truck, it will hesitate and run rough. A shot of gas will clear it right up, or if you let it sit it will clear itself up anyway.
Every so often it will be bad enough to throw a misfire code.
I've had:

P0300
P0306
P0301
etc.

Dealer hasn't been able to do anything. They've checked the entire ignition system. Checked a service bulletin on the coils and found that they are up to date. They just blame it on poor gas quality in Canada. I always run 91 octane from Shell. I doubt it's a gas quality issue, as other BMW's around don't seem to be having the same problem.

Once the truck warms up, it is fine for the rest of the day. It will only do it again if it has been sitting for an extended period. Atleast 6-8 hours.

Then again, other times you flick the key, and she will fire right up with no problem.

Any advice?

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amacman · #2 11-02-2009, 08:48 PM

bad fuel or burst diaphragm on the crank vent oil separator can cause this issue .
i do not know what the codes mean so if you can find out then maybe someone on the forum could give more idea as to what the problem is .

timx5 · #3 11-02-2009, 08:51 PM

Where can I find the burst diaphragm? I haven't played around in the engine bay on this thing very much since I bought it and it's still under warranty.

I've tried fuel from several different places. Lucas fuel injector cleaner as well.

Weasel · #4 11-02-2009, 09:11 PM

Intermediate lever wear can cause similar issues, I'd leave it with them overnight (making sure it is in the shop overnight) then have the diagnostic equipment hooked up to it to read the "smooth running values" when it is started for the first time... And there is also a test plan to raise the minimum valve lift at idle for diagnostic reasons.

amacman · #5 11-02-2009, 09:15 PM

the crank vent hose is on top at rear of left valve cover , it goes to oil separator to allow oil to drain back into engine then another hose takes gasses to diaphragm on rear of intake chamber.
see online parts catalogue on home page - E53 tips & tricks then take to dealer as it has warranty .

edit - there you go then , weasel has the answer just as i was typing this reply .

timx5 · #6 11-02-2009, 10:02 PM

Thanks guys. I'll try having a look myself before I go to the dealer. They've been like trying to squeeze water from a rock lately to actually fix something. Been nothing but small easily fixed ongoing issues, with months of waiting for parts and troubleshooting.

amacman · #7 11-02-2009, 11:22 PM

the crank vent system on your car could be different to what I previously described
a sure way to test for damage is to remove the air intake pipe from throttle where you should see a small pipe opening through which the crankcase gasses are drawn .
if you see engine oil from the small pipe that indicates a burst diaphragm .

wallyx5 · #8 11-03-2009, 12:04 AM

I had some similar issues with cold starts and found out that the intake boot was cracked and allowing air to enter after the MAF. Replaced the boot and problem fixed. But you took it to the dealer and I am sure they looked at that.

killcrap · #9 11-03-2009, 08:03 AM

Quote:

Originally Posted by amacman

the crank vent system on your car could be different to what I previously described
a sure way to test for damage is to remove the air intake pipe from throttle where you should see a small pipe opening through which the crankcase gasses are drawn .
if you see engine oil from the small pipe that indicates a burst diaphragm .

On a 2004-2006 X5 4.4L First of all Engine oil is designed to enter the Intake Manifold, this is to lubricate all the moving components. And second of all, the crank case vent valves are on the cylinder head covers, even a microcrack will cause the check engine lamp to illuminate(for NA vehicles). A completely torn diaphram will not have the same issues with the 3.0L or the older 4.4L.

To the OP, you will need to replace the intermediate levers and the most importantly the shafts as well. Each shaft is close to $1,000 in parts, that is why BMW wants to make sure thats the cause of the misfires.

01 BMW_X5 · #10 11-03-2009, 03:00 PM

Quote:

Originally Posted by Weasel

then have the diagnostic equipment hooked up to it to read the "smooth running values" when it is started for the first time...

Weasel

I was playing around with the GT1 and saw this test and recorded it. When running this test on a 4.4 engine; cylinder 8 does not register any values.
Is this normal?
No fault codes are stored.

Thanks

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