A little help please, misfires.

[jdstrickland]

From the Apples & Oranges Department,
I was chasing a misfire in my F150 that would go away when I pulled the plug out and put it back in. I convinced myself that there were signs of liquid that could be making a ground path that shorted the plug out. The engine would run well, then a misfire would appear on another plug. I had two plugs that were beating me up more than any of the others, more than all of the others combined, and I discovered that the connectors on the injectors fit kinda sloppy. I turned the offending injector -- the most recent one -- and the problem immediately went away. All I did was twist the injector a few degrees so that the wires in the connector had a load on them.

I'm just suggesting that if you have injector trouble then maybe it's electrical not mechanical. If you swap a coil and boot to another cylinder but the misfire remains in place, then maybe you have an injector that has a poor electrical connection.

[upallnight]

When you replaced the spark plugs were the spark plug holes filled with oil? Oil in the spark plug hole will cause the plug to misfire. Oil in the spark plug hole is from a bad valve cover gasket.

[g300d]

Could be air/vacuum.

Have you checked the big intake elbow going into the cylinder head, that likes to cracks at the creases over time.

The DISA valve also produces similar symptoms. Flap could be working its way loose or the valve operating intermittently.

[g300d]

Also for reference:

misfire diy for E46 330i

[SarTech]

Originally Posted by g300d

Also for reference:

misfire diy for E46 330i

Thanks, there is some good information there.
Got to finish up a god today but will get back to the car tonight. Thanks for the help.
PB

[SarTech]

Still no joy!
Last night I cleaned all the connectors that I could find and replaced a vacuum line that I had missed.
Drove into town (40 mile round trip) got lots of codes.
P1349
P1345
P1353
P0300
P1351
P1342
P0300

So I think my next plan is to replace the DISA valve and the O-ring on the throttle body.
What do you think? Any other suggestions?

Still wondering if the electronically controlled thermostat could be causing this? But from what I read the DME only send signals to the thermostat and does not receive any input from the thermostat????

[SarTech]

Originally Posted by upallnight

When you replaced the spark plugs were the spark plug holes filled with oil? Oil in the spark plug hole will cause the plug to misfire. Oil in the spark plug hole is from a bad valve cover gasket.

No oil in the spark plug holes.

[SarTech]

Originally Posted by g300d

Could be air/vacuum.

Have you checked the big intake elbow going into the cylinder head, that likes to cracks at the creases over time.

The DISA valve also produces similar symptoms. Flap could be working its way loose or the valve operating intermittently.

The big elbow is good. I had replaced that last year but checked it again. Its intact and can not find any vacuum leaks by spraying brake clean around while motor running.

[jdstrickland]

P1351 BMW Misfire Cylinder 5 With Fuel Cut-Off OBDII Engine Light Trouble Code | Engine-Codes.com

If you look at this link, one of the possible causes of the trouble is a poor connection of the ignition coil.

The meaning of MISFIRE is that the expected work was not performed. I forget the firing order, but if it is 153624, then when 1 fires the engine has to progress to 5 within a specific period of time, if the crank does not get there in time, then a misfire is declared.

A misfire can be due to a lean fuel mixture, poor spark, mechanical issues like burned valves, and other sorts of things. We like to work on spark, but that is not always the problem.

There is a code that means MISFIRE WITH FUEL CUTOFF, and you can feel this because of the shaking that takes place. The engine detects the misfire and stops fuel delivery so that raw fuel is not fed into the CAT -- the raw fuel will damage the CAT, so they want to prevent this from happening. You will not feel the misfire until the fuel is shut off, and then you feel the engine clear up when the codes are reset.

[upallnight]

Sure you didn't switch the vanos connector with the cam sensor connector?