E46 330i Intermittent Misfire

[De@nO]

Hi guys,

My E46 330i has an intermittent misfire.:thumbdo: Normally happens at least once a trip and usually lasts about a minute or two and then runs normally again. I have also noticed that if I turn the ignition off when it happens, then back on again, the motor runs normally and the misfire disappears.

Any thoughts, perhaps a faulty coil? or do i need to plug in a diagnostics machine?

 

[samman325]

Diagnostics will be a good start.

Is the misfire normally on first start up when engine is cold or any time?

After moving it a short distance? (like out of the garage into the driveway for a wash then back into the garage)

 

[De@nO]

Diagnostics will be a good start.

Is the misfire normally on first start up when engine is cold or any time?

After moving it a short distance? (like out of the garage into the driveway for a wash then back into the garage)

Seems to happen once the motor is at normal operating temp and iv driven +-5km

 

[Pho3niX90]

Remove the disa flap and inspect. Most probably that. Will take you 10 mins to remove.

 

[De@nO]

Not the DISA, did a repair on it not so long ago.
It is a definite misfire

I think the best is to plug in diagnostics?

 

[msm]

I think the best is to plug in diagnostics?

Yep - identify cylinder. Then swop coils around to see whether the fault follows the coil, as it's a common issue.


Disclaimer on this:
There is another way of doing it without diagnostics though. While the car is idling rough, remove one coil at a time and put it back. The cylinder that makes no difference when you unplug is your problematic cylinder. Might help to place a glass of water on the engine block to show the problem, if you hearing is not so good...

 

[Blomhj]

I had / have the same issue also E46 330i but normally under load it misfires , switch it off , back on again and its fine . Use to happen often when I bought the car , so replaced the fuel filter, found the one in to be the OEM one that was on when it came out of the factory . Opened the old one and it looked like the car was running on a graphite fuel mixture . Also bought a whole box of injector cleaner , filled two bottles per half tank and drove it like I stole it ....since then the problem only came back once. Theory is that the Fuel Pressure Regulator is integrated into the filter that the diaphragm wasn't performing according to spec due to its age and not delivering optimal fuel pressure to fuel rail, well that and the filter was blocked. Best way is to check your codes to pinpoint it. But if you haven't changed your fuel filter in a while that not a bad place to start .

 

[GPGrobler]

Short question about changing the filter:

Anyone have an idea on how to remove this or any other fuel filter under the car without getting doused in petrol?

At the moment this is what is making me hesitate to do it - my hands, arms etc. is soaked in petrol every time I work on the filter(s) because the fuel filter is normally filled with fuel, and in the case of the E46, I guess this to be close to half a litre!

---

Short question about changing the filter:

Anyone have an idea on how to remove this or any other fuel filter under the car without getting doused in petrol?

At the moment this is what is making me hesitate to do it - my hands, arms etc. is soaked in petrol every time I work on the filter(s) because the fuel filter is normally filled with fuel, and in the case of the E46, I guess this to be close to half a litre. So I expect to be showered with the stuff!

 

[Blomhj]

I depressurized the fuel rail at the valve , used rags around it to catch fuel then just placed a flat ice cream bucket under the filter loosen the one side and let it drain.

---

this is the gunk that came out , this is just draining the fuel out of the filter


http://s22.postimg.org/59hgi28lt/20140727_154305_resized.jpg

If you have those anti tamper hose clamp on you know its still the factory fuel filter

 

[Pho3niX90]

Not the DISA, did a repair on it not so long ago.
It is a definite misfire

I think the best is to plug in diagnostics?

What was the repair? Disa causes misfires! You can find my thread when the 330i was misfiring. Also pcv causes random missfires.

 

[Peter@AEW]

Not the DISA, did a repair on it not so long ago.
It is a definite misfire

I think the best is to plug in diagnostics?

What was the repair? Disa causes misfires! You can find my thread when the 330i was misfiring. Also pcv causes random missfires.

.......and we know all about that don't we just.

 

[Bazza]

I had the same issue, everyone said it was faulty coils. I had a fault code of misfire on cylinder 2,4 and 5. Ended up being the grommets around the spark plugs which had worn out and tiny amounts of oil leaked into the spark plug cavity. When you remove your coils to check them take a good look inside around the spark plugs and see if there is any oil.

 

[GPGrobler]

Does anyone have a screen print of an INPA graph which shows the cylinders under normal conditions?