Intermittent starting issue with E85 Z4

[donaldgibson]

Hello,
I have a 2009 E85 Z4. It starts intermittently. Sometimes it starts completely fine, other times it doesn't crank at all and I just hear a single click from somewhere under the hood. I have to then turn the key back and forth until it finally starts up normally. Sometimes it takes just two attempts, but sometimes 25+.. It also seems to only occur when the engine is already warmed up. I'm worried it'll eventually just stop working completely and leave me stranded. My battery is a pretty new oem AGM unit and the connections seem fine and clean. All my accessories and headlights work fine with the engine off. I don't think it's the clutch switch because if I turn the key without pressing the clutch, there is no under hood click sound like there is when I press the clutch.
Any advice is appreciated! Thanks in advance!

 

[enuff_zed]

Good morning. Sounds like the starter motor. The click is the solenoid making the connection within the motor but it is then not turning the engine over. If everything was dead I would suggest the ignition switch, but that click leads me back to the starter.

 

[chanlon1]

I would hazard a guess that it may be the earth ground strap. Your symptoms were very similar to mine. I swapped out the starter motor but it made no difference. By that stage my engine refused to crank.
The ground strap was replaced and the car feels brand new.

 

[chanlon1]

Have a read of this thread to see if yours sounds the same…..

https://z4-forum.com/forum/viewtopic.php?t=146806