Engine trouble - United Bimmer Community

**onelifeak** · 07-20-2009, 10:45 AM

Hi everyone, I am having trouble with my 3 series and I was wondering if anyone could help me figure out the problem. When I drive the car I randomly lose power in cylinder 2 but if I turn the car on and off while driving it goes back to normal. Sometimes it doesn't come back that day and sometimes it occurs soon after reseting. I have replaced the injector, plugs, done a compression test, and I still do not know why this is happening. I was thinking that maybe something in the engine wiring is being pinched and randomly shorting out but do not know for sure. Any ideas?

**3050rpm** · 07-20-2009, 11:13 AM

I've got to ask a basic, clarifying question... how do you know you're losing power specifically in the #2 cylinder?

**onelifeak** · 07-20-2009, 12:03 PM

My father is a mechanic and he was helping me diagnose the problem and he was saying that the misfire is in cylinder two. I am always up for suggestions as to how I can test to make sure where the problem is. I am not personally positive it is on #2 but my father did a few tests and narrowed it down by switching a few parts in and out to see if the parts were bad or the specific cylinder was the problem.

**3050rpm** · 07-20-2009, 12:44 PM

Okay, so there's some assurance that it's from that cylinder... Hmmm, gotta think now...

**3050rpm** · 07-20-2009, 04:51 PM

What about the coil, has your father swapped it out on the #2, or checked the resistance?

**onelifeak** · 07-21-2009, 07:40 AM

Yes the coils have been changed.

Big Evil · 07-21-2009, 10:11 AM

Then it's most likely wiring to the coil pack or the driver in the ECU is shorting out. Could be a loose/bad connector, but you description seems to lead towards an electrical fault. Any codes pop up?

**onelifeak** · 07-21-2009, 11:15 AM

Thank you for the help I am going to check out the wiring and ECU and see how that works out. I will post my results once I figure it out.