Cylinder #3 Misfire when cold

[Dutchman71]

I am glad that the head is not cracked. Injectors can definetly fail, but as you said when you restart the car its fine. That points more to a software issue.
I let the dealership reprogram all three of my BMW 's software. I think they charged me two hours of labor per car. Around 290 dollars.
Did you check your fuel pressure. It should run between 50-52 psi.
After you shutdown the car, is it holding pressure? The pressure will bleed off slowly after a couple hours, but it shouldnt bleed off within an hour.

[mdfiasco]

If the misfire doesn't follow the injector, then I'm leaning toward DME. I understand that the MS42 dme is not reprogrammable, so I may need to buy a remanufactured or oem dme.

[MarcoZandrini]

If the misfire doesn't follow the injector, then I'm leaning toward DME. I understand that the MS42 dme is not reprogrammable, so I may need to buy a remanufactured or oem dme.

I believe all DME's are re-programmable. Check with the dealer or a good independent BMW mechanic.

[mdfiasco]

I believe all DME's are re-programmable. Check with the dealer or a good independent BMW mechanic.

I'm finding very little info on the MS42 DME. The guys at Bavarian Auto Recycling (bmrparts.com and a forum sponsor) claimed that the MS42 is not swappable between cars. When I asked why they sold them, the dude couldn't tell me. My Indy claimed he's never seen an MS42 fail. So, we'll see.

I swapped injectors around last night. If it doesn't follow the injector then I'll start getting into the DME.

As of yesterday morning/afternoon and today, there has been no rough idle and no SES. Temps have come up above 50 degrees and I think this is a coldstart and cold weather issue. If I can't get an SES in the next few days, I'm gonna put ice packs around the coolant temp sensor, kidney grill, and MAF to try to force the issue.

[Dutchman71]

I know that the LCM is not programmable, but I believe the DME is programmable. I have a 325i 2003 which had some transmission problems, which were caused by DME software issues. After the car got reprogrammed all problems were solved.

[mdfiasco]

I know that the LCM is not programmable, but I believe the DME is programmable. I have a 325i 2003 which had some transmission problems, which were caused by DME software issues. After the car got reprogrammed all problems were solved.

We have different DMEs. I have the Siemens MS42, you likely have the Bosch MS43 or above.

[MarkoE46]

The guys at Bavarian Auto Recycling (bmrparts.com and a forum sponsor) claimed that the MS42 is not swappable between cars.

It's not swapble beetwen cars because you can't reprogram it to an another EWS code.

[ninetyseven1]

It's not swapble beetwen cars because you can't reprogram it to an another EWS code.

Did u ever solve this issue?? i have a 97 540i V8. Exact same symptoms. Only get cylinder 3 misfire if car is cold or sits overnight. I can stop it by giving it some light quick throttle, but still runs rough until engine is warmed up. issue is gone when car is driven a few miles or so. I have tried everything so far except a compression test, swapping DME's, and also have not tried swapping injectors yet.

[ninetyseven1]

I am pretty sure its not a bad coil, or coil wiring, all injectors ohm out to the same, no loss of coolant, car runs like a champ when warmed up.

[SilverSaloon69]

I am pretty sure its not a bad coil, or coil wiring, all injectors ohm out to the same, no loss of coolant, car runs like a champ when warmed up.

Go ahead and swap the injector to a different cylinder. If the injector is leaking, this will cause a cold start misfire and will follow to the cylinder it's swapped to.

[daytonatrbo]

My car is doing basically the same thing as OP. #3 cylinder is consistently weak/misfiring on cold starts, and sometimes will go to the point of the DME shutting off fuel to that cylinder. At one point, I had a coil die, and I thought that may have been the issue all along, so I replaced all 6 with new Bosche units. The problem remained.

More recently, it developed new symptoms: After sitting for over a week, I couldn't get #4 to fire at all. After clearing the SES codes for misfires, and resetting a few adaptations, I got #4 back and lost #3.

After cleaning a VERY small amount of crud off the spark plug in #3 it came back online. The plug was BARELY wet with fuel after idling for some time with absolutely no fire on the cylinder, despite having good strong spark and the injector audibly clicking when probed.

Based on this, I have concluded that I probably have a weak spray pattern on #3 injector, and possibly others. I don't think I have a fuel pressure issues because the cylinders that fire consistently, run strong. And I have a fairly new fuel pump and filter/regulator.

I plan to run a dry/wet compression test on my engine to eliminate weak compression as a contributing factor, then I will be replacing all 6 injectors with freshly serviced units.

[Nsaoby]

Gents I am now in the same boat with my 2013 E92 M3.

Environment: outside temp < 40 degrees Fahrenheit. Only happens in the cold and after the car has been sitting long enough for the engine to completely cool. Car "appears" to run fine after it is warmed up (7+ minutes).

Symptoms:
During cold weather start, car throws faults after 10 seconds or so; sometimes going into limp mode. I then kill the ignition and restart (sometimes multiple times) and the issues go away.

Faults are misfire cylinder 7 and increased emissions.

I have been in the shop three times now over the last month and tired of pissing money away to their guessing. The spark plugs, ignition coil, and injector for cylinder 7 were replaced. After each service the issue clears up for a day or two at best, then rears its nasty head again.

Seriously looking for assistance from those that had and rectified this issue!!!

[daytonatrbo]

Mine seems to have burnt valves. very low compression on 3 cylinders. Symptoms come and go as valves find new seat.

[ninetyseven1]

Gents I am now in the same boat with my 2013 E92 M3.

Environment: outside temp < 40 degrees Fahrenheit. Only happens in the cold and after the car has been sitting long enough for the engine to completely cool. Car "appears" to run fine after it is warmed up (7+ minutes).

Symptoms:
During cold weather start, car throws faults after 10 seconds or so; sometimes going into limp mode. I then kill the ignition and restart (sometimes multiple times) and the issues go away.

Faults are misfire cylinder 7 and increased emissions.

I have been in the shop three times now over the last month and tired of pissing money away to their guessing. The spark plugs, ignition coil, and injector for cylinder 7 were replaced. After each service the issue clears up for a day or two at best, then rears its nasty head again.

Seriously looking for assistance from those that had and rectified this issue!!!

Are you sure they replaced the injector?? I had this exact same issue for almost a year and we tested everything. I replaced the spark plugs, coil, tested wiring from coil to DME, tested wire from injector to DME. Replacing the injector fixed it. I also made sure my valve cover gasket was good and not leaking oil onto my spark plug and coil. If you replaced all of the above then the issue is wiring or a bad ecm.

[Nsaoby]

I am fairly sure it was replaced (replacement took place on Tuesday).....I know they charged me for one. So this morning it was 38 degrees outside and it threw the faults again. However this after noon after 10 hours the faults didn't return. I have cleared all faults and will review again in the morning.

[ninetyseven1]

I am fairly sure it was replaced (replacement took place on Tuesday).....I know they charged me for one. So this morning it was 38 degrees outside and it threw the faults again. However this after noon after 10 hours the faults didn't return. I have cleared all faults and will review again in the morning.

It has nothing to do with the outside temperature. Its the engine temp. Mine did this, if i didnt let the car sit and warm up and rev it a few times when the engine was cold. Then I would get misfire on cyl 3. Then all was fine when engine was warmed up. Then the next morning I go to drive car and the code was back. When u get a cylinder misfire code, the fuel is shut down to that injector. When u clear the code the fuel is returned and it could still be a bad injector. Test the wiring between the injector and the DME and do the same for the coil on that side. Test the wiring.

[Nsaoby]

I only have issues when it is cold outside, which affects the engine temp after its been sitting overnight. This has also been replicated and confirmed by BMW.
When it has been above 45/47 degrees F I have had no issues. When the temp outside drops I have issues.

Also on clearing the code - I do not have to clear the fault codes for the care to return to normal operating parameters. Even if upon cold start the car goes into limp mode, I fully turn the ignition off, crank her back up, and away i go with full power etc. The faults are still present as confirmed by scanning prior to and after running normally.

I will post the fault codes shortly....As stated above - cylinder 7's plug, coil, and injector have been replaced. The wiring was also tested by BMW. I am reaching out in hopes of finding those who had the same issue (i.e. misfiring only in cold weather at start up) and fixed the issue. A good friend (mechanic) says it is possible to be the throttle actuator. A year ago, I replaced the whole left bank and throttle actuator with similar issues, so this is definitely in the realm of possibility. My fears are that its a head issue....Which means I need to once again take it back to BMW and let them do a compression test since I don't have the equipment.

[ninetyseven1]

I only have issues when it is cold outside, which affects the engine temp after its been sitting overnight. This has also been replicated and confirmed by BMW.
When it has been above 45/47 degrees F I have had no issues. When the temp outside drops I have issues.

Also on clearing the code - I do not have to clear the fault codes for the care to return to normal operating parameters. Even if upon cold start the car goes into limp mode, I fully turn the ignition off, crank her back up, and away i go with full power etc. The faults are still present as confirmed by scanning prior to and after running normally.

I will post the fault codes shortly....As stated above - cylinder 7's plug, coil, and injector have been replaced. The wiring was also tested by BMW. I am reaching out in hopes of finding those who had the same issue (i.e. misfiring only in cold weather at start up) and fixed the issue. A good friend (mechanic) says it is possible to be the throttle actuator. A year ago, I replaced the whole left bank and throttle actuator with similar issues, so this is definitely in the realm of possibility. My fears are that its a head issue....Which means I need to once again take it back to BMW and let them do a compression test since I don't have the equipment.

Take your car to several "other" independent mechanics , dont trust the BMW dealer at all.

[ZenZdude]

Reviving a thread
I have the exact same problem with my 97 Z3 2.8 @ 168k miles. Misfire Cyl3, sometimes cyl4. Rough idle starting 10-15 seconds into start, only from cold engine, and worse when cold outside. If I rev it a few times and drive off, no CEL, no code. If I leave it idle, it pretty much always throws the code. Swapped coils around, new plugs, new boots, cleaned MAF, did smoke test with homemade smoke tester rig (gallon paint can, rags on fire haha). Haven't swapped injectors--might have to try that. Haven't done compression test. Cleaned ICV, seems fine, tested with power supply and it opens and closes. Replaced grommet for ICV. Just checked O2 values using ODBII Actron reader. Post cat O2 seems to swing a lot (like pre-caty) when blipping throttle and holding at various RPM's--I thought it was supposed to stay relatively constant? Replaced caty approx 20k miles ago with Magnaflow one--supposed to be a pretty good one. I do notice rotten egg smell--that's unburnt gas through caty, right? Not good for caty either, right? Can kill one if done longe enough.

Other than the small head crack issue (shudder), has anyone fixed this issue? Mine's been like this for 2 years and it's friken annoying. My local whiz says prolly old injectors slowly bleed and cause localized (per cyl) gas flooding that takes a bit to clear--and that a few decent throttle revs upon start should blow it all out. That actually seems to work, but I hate revving a cold engine, and the rotten egg smell is annoying as well.

[ninetyseven1]

Reviving a thread
I have the exact same problem with my 97 Z3 2.8 @ 168k miles. Misfire Cyl3, sometimes cyl4. Rough idle starting 10-15 seconds into start, only from cold engine, and worse when cold outside. If I rev it a few times and drive off, no CEL, no code. If I leave it idle, it pretty much always throws the code. Swapped coils around, new plugs, new boots, cleaned MAF, did smoke test with homemade smoke tester rig (gallon paint can, rags on fire haha). Haven't swapped injectors--might have to try that. Haven't done compression test. Cleaned ICV, seems fine, tested with power supply and it opens and closes. Replaced grommet for ICV. Just checked O2 values using ODBII Actron reader. Post cat O2 seems to swing a lot (like pre-caty) when blipping throttle and holding at various RPM's--I thought it was supposed to stay relatively constant? Replaced caty approx 20k miles ago with Magnaflow one--supposed to be a pretty good one. I do notice rotten egg smell--that's unburnt gas through caty, right? Not good for caty either, right? Can kill one if done longe enough.

Other than the small head crack issue (shudder), has anyone fixed this issue? Mine's been like this for 2 years and it's friken annoying. My local whiz says prolly old injectors slowly bleed and cause localized (per cyl) gas flooding that takes a bit to clear--and that a few decent throttle revs upon start should blow it all out. That actually seems to work, but I hate revving a cold engine, and the rotten egg smell is annoying as well.

Replace injector on cyl 3

[drdirtg]

Hey guys,
I am having the same exact problem on Cyl 3 on my s85.
Misfire only on cold start/after sitting for 8 or more hours. I changed the plug, injector, and coil, swapped maf sensors from bank to bank, swapped vanos valves around, still nothing.
I can get it to not fault out on a misfire by starting the engine and after 2 or 3 seconds shutting it off - then start again and after 3 sec off, and again and again, 4 or 5 times and it will run on the 5th or 6th start without faulting with a misfire.

Did any of you get to the bottom of this issue?

[shew show]

Add one more to the list.
Having same trouble. Cyl 3 & 5 injectors not firing until warm up.

[shew show]

I see the last response before me was over a year ago but did not see a solution. Anyone fix their issue?

[Jackson42]

I've got exactly the same problem on my '04 330Ci, but mine is on #6. Sometimes I get a generic #6 misfire code; sometimes not; sometimes the CEL comes on and then spontaneously goes away; sometimes it latches a P0306; sometimes it continues to run rough. Occasionally this will occur while at cruise on the highway. But in all cases, it clears when I shut off the ignition and restart. Baffled.

[Eli87]

It is definitely an electrical problem !
It hat nothing with engine warming there there ist a battery problem