BMW E90 rough idle on cold start

[Mohammad]

Hi, i have an E90 323i. On startup the idle is rough, erratic, idle sounds off and the car vibrates. Once the engine seems to heat up the idle stabilizes. I scanned it for codes and it read codes P0301, P0302, P0303 (misfiring cylinders 1,2,3) and P112C. Anybody experienced this before or might know whats causing it?

 

[momo1]

When last have you changed your plugs and fuel filter?

 

[yush1]

Could be injectors.

 

[Mohammad]

When last have you changed your plugs and fuel filter?

Did a major service a month back. Oil, oil filter, air filter and spark plugs

 

[akash]

You have misfire codes, so it could be the plugs or coils packs, I doubt it’s the injectors since it’s a 323i N52 engine and they don’t have direct injection like the N54, that had injector issues.

Since you did change the plugs (make sure the right plugs were fitted and/or correctly gapped). I would swap the coil packs from the cylinders were the codes appear, to working cylinders and see if the code travels with those coils, if they do you found the problem.

 

[momo1]

Well if it helps, about a year ago I had a slight rev dance on a cold start up with my Z4 that also has an N52 3.0 , threw in some liqui Moly injector cleaner, filled a full tank of fuel and did a 150km drive of spirited driving, it solved my problem and didn't cost much.
although mine didn't throw out any warnings.

 

[Mohammad]

You have misfire codes, so it could be the plugs or coils packs, I doubt it’s the injectors since it’s a 323i N52 engine and they don’t have direct injection like the N54, that had injector issues.

Since you did change the plugs (make sure the right plugs were fitted and/or correctly gapped). I would swap the coil packs from the cylinders were the codes appear, to working cylinders and see if the code travels with those coils, if they do you found the problem.

Thanks, will try that.

 

[maverick328]

Hi, i have an E90 323i. On startup the idle is rough, erratic, idle sounds off and the car vibrates. Once the engine seems to heat up the idle stabilizes. I scanned it for codes and it read codes P0301, P0302, P0303 (misfiring cylinders 1,2,3) and P112C. Anybody experienced this before or might know whats causing it?

Check your rubber intake boots for cracks. It will cause rough idle on start up and eventually settle. Had that issue with my 330i

 

[Nikhil]

Seen this with another members car not to long after he serviced it coil packs were loose. Remove them and refit, press then down firmly to ensure they are seated correctly