Rough idle cold start CEL on 325XI
 

Hey all. Just bought a 03 325xi a couple weeks ago and its been great. so far i've replaced all spark plugs NGK OEM, OEM fuel pump and fuel filter, and changed the oil and oil level sensor.

Ive been having a problem sometimes when its cold out and trying to start the car. It starts fine but idles rough and CEL is on. I try to accelerate and it seems like it feels like it runs of 4-5 cylinders. as soon as i get it to operating temp, and shut the car off and turn it back on CEL is gone and idle is fine and smooth.

what could be the problem? i did notice that i have bosch coil packs on 1-2 and 5-6 and bremi on 3-4. should i replace the bremi's? Please let me know guys! thanks.

Step 1.) Scan for codes

Step 2.) Tell us what the codes are

We'll get to what happens next after we know the codes. What you've described doesn't sound like coils but we'll see when you get us the codes. Did this happen immediately after you did any work or has it cropped up over time?

I will try and get codes, its hard to duplicate the problem as this was only the 2nd time it has happened. It only happens during weather conditions are cold but after 2 mins of driving and shutting down the car and starting it has fixed the problem.

I've just replaced those parts as preventative maintenance but it has happened once before i've done the repairs.

Start it up in the morning and drive straight to the auto parts store, leave it running with the CEL lit and go inside to get the code reader. Then proceed to scan for codes and post on here.

I'm pretty sure that the code gets stored until you clear it anyway regardless of if the light is on or not. So just get it scanned.

Im also interested to know what codes you get. My car has the exact same problem you have described. The only code it ever throws is Misfire Cyl 3, i have swapped coils and plugs, all with the same result. Even replaced plugs and coils over the summer, still same problem when it gets below 40 degrees.

One odd thing i have found, is when it starts running ruff and i clear the code, it immediately runs smooth?

Finally the code stored and I was able to get cyl misfire #2. I've just changed the spark plugs but it has happened before that... 3-4 coil packs are bremi and 1-2 and 5-6 are Bosch.... What could be the problem???

Looks like coil packs are a likely culprit since someone already replaced some. Try swapping them around to see if it follows the pack.

I've done a bit of research but could it be the actual lifter?? I do get some tick during start up for a couple seconds and disappears

Doubt it.

I forget which are the good ones, Bosch or Bremi, but my money is on the coil as well. Other thing to check is the connections to each coil and the ground wire. Maybe something just loosened up?

Question, when you changed the spark plugs, you removed the coils, was there any oil on the bottom of any of the coils where they fit onto the spark plugs? Was there oil on any of the spark plugs? Was there any oil in any of the spark plug wells? If the answer to any or all of the previous is yes, then you have first got to replace the valve cover gasket set. The "o-rings" that seal the spark plug wells get hard and crack long before the outer valve cover gasket does. The coils do not like oil and it will cause a misfire. If any of the coils did have oil on their boots (and by the way, did you replace the coil boots when you changed the spark plugs, you should have), you may well have to replace that coil or coils. Bosch coils are fine to use. If you tore any of the coil boots when pulling off the spark plugs, you can have spark leakage to the spark plug well that will also give a misfire. So, re inspect the boots and I would recommend replacing the boots. When putting the new boots on and before pushing onto spark plugs, put a little di-electric grease on the inside of the boots so that they come off the plugs easier (doesn't have to be a lot, just a thin coating). If all that checks out and you still have just a Mis-fire on one cylinder, it could be several other things including the DISA Valve. When the DISA Valve is broken, too much or too little air can get into the intake runners and cause poor idle sometimes, and other times idle fine, and it will usually throw random mis-fires across all 6 cylinders. When you had the code(s) read, did you have them reset? If not, have them read again and reset, do your repairs and look for the CEL/SES light to come back on and then have codes read again.

Codes have not reappeared, I ordered a oem Bosch coil pack to put on #2 cyl, if problem persists, I think it might be a bigger problem. Valve cover gaskets were replaced before I've owned the car, only oil I've noticed was on 1 of the spark plug threads..

Definitely check intake boots for rips. I would order six new Bosch coils from rockauto.com if you go that route. Are you scanning with a Peake tool? If so, there's a specific code for a bad coil, which is different from a misfire code.

What kind of plugs are in there? Make sure they are all the same.

You need more oil. Fill it so it reaches the top mark on the dipstick when the motor is cold. Then add another 1/2 quart. Oil level below the top mark on an xi is too low, IMO.

I just put 7qt of oem synthetic BMW oil, lol

Check oil level, if you added 7 qts and then started you might very well be low on oil. Lifter tick doesn't happen unless you have a sludge problem and/or low oil pressure/level. Make sure neither is the case.

update: well the problem came back. it was -20 outside trying to warm up my car a week ago. i get a check engine light and all of a sudden engine feels like its running rough. same code misfire cyl 2. i have since replaced all plugs and the one coil pack that was the problem in cyl 2. what could be the problem?? my indy mechanic says to replace all coil packs which I think is BS.

Swap coil packs around to see if misfire moves with the coil.

i already replaced coil pack on #2 last december. fault still persists that cyl 2 has misfire. all spark plugs are changed....

just read this on another forum.. "Well, when the lifters go bad in these motors, the lifter collapses and doesn't lift the valve all the way; meaning the cylinder isn't getting a complete air/fuel charge. The lifters scour the lifter bore in the cam ledge, creating escape passageways for the oil to travel instead of pumping up the lifter."