Was this a one-time code or recurrent? I would ignore it if it doesn't repeat. Yeh it's not going to be anything that's not cylinder specific unless you start getting codes for other cyls.

 

It's recurrent. I can clear it and drive around for about 5 minutes before it comes back.

 

Do you have INPA? Check your fuel trims.

 

Unfortunately, I only have BMW Scanner 1.4 (PASoft) and I don't believe you can check fuel trims on it.

 

Not sure if that makes sense or not. That code is suppose to be misfires in the first 1000 rpm of start up. That takes no more than 1 1/2 mins. Might take awhile for it to get thru all the reporting. I have written about this before so here is the short form. It is usually a misfire on the exhaust stroke, spark fires on each stroke in the first 1000 revs.
More often than not it is a bad mix. The cyl fires on the exhaust because the first mix was to rich so mix was left over. This can come from many things but your choice of injector is next so do that. The other thing to consider is that it is the opposite cyl too lean. That would be cyl 5.

This could also just be an indicator of overall health. If lets say you have not done any vanos maintenance or maybe you have some carbon buildup on the exhaust valves or a combo of both. Although only 1 cyl is reporting the others could be on the verge. Frequently misfires on start is the vanos, because you only have one I think you are following the correct path, but if the injector does not do anything you should think vanos.

 

I'm not sure I understand what you are saying regarding the opposite cylinder leaning out? Wouldn't that cause its own code?

Yea I am going to take it one step at a time and hope for the best. Injector and O Rings are next. Compression tests etc.

I was just curious to know if anyone has had an injector fail before. I also read a lifter or even the DME can mess up as well as cause the same issue in rare cases.

 

Vac leak in the ITB boot for cyl 3 or 5 might be a consideration. Are you having rough idling? Does it happen at both cold and warm start?

 

Yes the idle is intermittently rough and it is both cold and warm starts. Also inbetween 1st and 2nd gear semi quick shifts under load, the car bucks horribly to the point where I have to let off the gas completely and then proceed to accelerate again.

Forgive my ignorance but should I maybe try swapping the plugs and coils on bank 2 (cylinder 5 ) to see if the code changes before I do the injector? I still do not understand how cylinder 5 comes into play with all this as even the scanner live data showed misfire at start up on cylinder 3 up to 285 and the others showed 0.

 

Somewhere in the WDS it says that it fires twice in the first thousand. Specifics I don't recall but I know the OBDII rules and what is trying to be accomplished. What little it spoke of it in All Data it made it clear that is was a fire on the exhaust and looking for acceleration. All data is general for all cars in that group. Think the M5 had its own group, don't remember for sure. The other thing is if it does not fire twice then that code should not be used because that code is for a misfire on the exhaust. It is an OBD code, albeit manufacturer.

I can't say what you saw, never looked, but there might be some perimeters that have to be met? Maybe your car did not meet them. It is a function of enrichment I thought? We have run into it before and it has always fit the model as expected. I myself have had them and the unrest was not showing a misfire as one would expect. That said I don't have much to compare because I use a scanner not INPA.

68 I can't say for sure, just the model has always held true. I can say on my car when I had those codes because of vanos it was not a misfire on the charged cyl. Maybe you should look on the low side, possible your DME decided you did not have a strong enough battery to fire twice and make recovery. Maybe you might see aborted voltage on the low side?

 

That is significant. What scanner are you using?

 

If you saw a 285 then it must be coil or injector.It is allowed that manufacturers to write what they want for their codes. Can you put your scanner on generic and see if you get the P0303, that might help understand if the car does in fact fire twice.
It would be nice to know for a fact if the car fired twice because it could be a coil that does not recover well. It sounds more like injector might be dripping or not capable when cold. You could do a fuel pressure hold check. The fuel system should hold the low pressure when turned off, even if it does not that does not mean it is an injector it could be some other things but it certainly would be an indicator.

You bought an injector put it in, that is a no brainer. Injector is one of the front runners and you have switched coils.

I have been thinking why this holds the model if it does not fire twice and it is sort of moot. There are only a few things that can cause this and stop causing things as the car warms. Or because they operate differently after the first 1000 turns. Things like air leaks don't go away after the first 1000 and should show other symptoms.

 

The code I def have is p1346. The live data was viewed on a snap-on scanner.

I know it went up to 285 pretty quickly and then slowed down but I only watched it for a minute. After it was for a couple minutes and looked at again, it was still at or around the same number so I believe the misfires slowed down or the car was "accounting" for it so they slowed.

P1346 is the only code I have been getting pertaining to this misfire the whole time.

 

I have yet to swap the injector. I am waiting for it to arrive in the mail. I was curious to know if there was anything else that I should try in the interim and it sounds like people are saying to swap coils and plugs on cylinder 5?

 

Could be the injector dripping overnight and taking a while for the cylinder to clear itself out on a cold start, as sailor is suggesting.

With a recent thread on leaking head gaskets in mind, a compression test or leak-down test on the cold engine would be something you could do. Hopefully it would rule out rare and obscure stuff like a head gasket leak that seals up on heat-up, lifter collapsing overnight, valve sticking and freeing.

Malcolm

 

If you want to try something else drop a bottle of injector cleaner in the tank. Techron from chevron.

Just for the sake of it, I would never move a sparkplug, might change it. Not sure moving coil 5 will do anything but it is likely worth checking that bank for good grounds and good boots, you could swap the coil then. Personally I would do the fuel pressure check as it would tell you much more and may identify a different problem. There are several threads but basically hook up the gauge and if the pressure drops pinch off one of the three lines at a time to see which line stops the drop.

 

Yeah I added the Techron last night and took the car for a couple "spirited" runs and actually it seemed to run a lot better. It wasnt perfect but the engine seemed a lot smoother. I decide to take the car this morning to work and it was back to being lumpy and hesitating...

 

I just received the injectors and hopefully I get around to doing further diagnosis on this this weekend.

 

Guys,

I had misfires on cyl 1 as well and I was told to change my TB gaskets which I did to no effort. Next I sent injectors out for cleaning and the misfire didn't comeback but I only had a misfire that would trigger in hot temps.

I still get high readings upon startup on several cylinders. more headaches.

 

Try replacing the MAFs if they haven't been done in a while or are original. I got a misfire on startup code and replaced both MAFs and had quite a noticeable difference in power and no more misfire on startup.

 

Update: Over the weekend, we took everything apart to replace in the injectors and realized that all the OHM measurements were fine. We decided to leave them and then swap the spark plugs from 1 and 4 with the ones from 2 and 3. As a result, I have been driving the car around for a week with no check engine light and the car pasted inspection!!

 

It may be fixed but just to let you know, the ohms measurement just tells you the injector solenoid coil is ok, it doesn't tell you if the injector pintle is sticking or if the seat is damaged and leaking. So if the problem comes back, it may be an injector.

Malcolm

 

Good point!!! Luckily I have 8 extra injectors.