Car won't start

[Tall Z Driver]

My 2003 3.0 manual won't start, so any tips would be appreciated.


Symptoms:
- Car would make a brief grinding "kkkkkk" noise upon starting, which is caused by the starter motor not disengaging quickly enough from the flywheel...sign of a failing starter.
- Every now and then the car would not even crank / start, but usually would within a few tries
- Completely stopped starting - won't crank. All lights on the car turn on, and no signs the battery is dead.
- I turn my key all the way, all lights come on dash, but then nothing happens.

Steps taken:
- Replaced starter motor (Got it to turn on twice)
- Replaced ignition switch (Got it to crank once, but only for a second and then it shut off before it could fire up the engine...)
- Tried multiple keys
- Tried cleaning any gunk out of the key


It looks like the problem is that the starter isn't getting power. Not sure if it's a bad connection, immobilizer issue, communication problem with the key, or what else it might be. I really don't want to tow it to a shop if I don't have to, and am going to scan it for codes tonight and test the battery with a multimeter.

Really appreciate the help, I just want to drive her!

[Tall Z Driver]

Update: Tested the battery with a multi-meter with the car off and it was reading 12.8, so that's not the issue. I also was able to start the car a few times, and with the engine running it was 14+. Also scanned it with the C110 for any codes related to immobilizer or other things and didn't get anything.

[Clearancediver]

Grounding strap corroded…. Clutch stop issue…

Two possible causes…

[drocket77]

Well, seeing as you did get it to start, I was suggesting the 5 fuses near the ECU under the hood. the center one is a 40 if I remember, and that one was blown. It wouldn't allow my car to start. It would crank but never start.
In the top left of this pic, you can barely see the 5 fuses. It is a PITA to ope also.

[bikesbikesbikesbikes]

did you fix it yet?

[bikesbikesbikesbikes]

I can come to philly friday night and we can put her in her place. I'll be in the van with my bike/tools.

[Z4MC Junkie]

I had a bizarre starting issue for a few years with my 2007 Z4M Coupe where I’d turn the key, the console lights would come on but the starter did nothing. I found that if I then hit the hatch release button, get out the car, open the hatch and get back in the car, the car starts right up. What made this issue even more bizarre was that it only happened in warm weather after the car had been sitting in the sun. Car started like a champ in the fall, winter and spring. I took it to my local MB/BMW mechanic multiple times and he replaced the battery, alternator and clutch switch but the issue would not gone away. The issue was finally solved by installing a new clutch master cylinder. According to the mechanic, the original one was "wobbly" and therefore would not always make the necessary contact/connection required for starting. I'm now able to start my car after it has been sitting in the sun - what a luxury! This issue was by far the most frustrating issue I've ever had with any car. Hope this helps.

[PeterSch]

I had the same problem on a 2007 Z4, and I've read about many times on the internet with various fixes. I put up with it for a year, and yes I cleaned every battery connection and whatnot between the battery and the starter like a pro. Charge and static voltage was always good. Also, holding the key turned all the way to crank for a couple or three minutes without releasing it, and the starter would suddenly engage and crank.

Finally the battery died of old age one winter morning with a dead cell and like 10v at best. I put in a new battery and I haven't had trouble since. Duh. It's been 2 years now.
In retrospect, maybe I should've tried jumping the battery off to see if it would crank.

One more thing, if it is a clutch switch, or any other kind of series interlock, you will not hear the starter relay/solenoid struggling to engage with a k-k-k-k-k sound; there will be no noise at all.