I am having a problem with my 2007 BMW 328i it will not crank/start but the lights and everything is working. I changed the fuses, starter, radiator, put a new battery in it, and a relay switch. and still no crank/start. What do you think it is, I need help????
A very common cause of no crank on BMWs of this era is the ‘ground strap’ failing. It is a short, braided wire which connects your left hand side engine mount to the chassis. (Driver side in US, passenger side in UK). The part is around $30, and it’s a relatively simple fix.
Replacement should take about an hour, and will be easier if you can lift the vehicle and remove the left side front wheel (driver side in US, passenger side in UK). It’s hard to see, so requires a bit of hand work, but is definitely doable. I’ve linked a video and forum post on the replacement. The forum post is an M3, but the process is very similar. You will not have a “header to X-pipe connection” next to the ground strap, but the strap is in the same location.
I have fixed issues like yours on a few BMWs by repairing a broken ground strap on the right side of the engine. It goes from a bolt just above the exhaust manifold to the body a few inches away. You may need to remove some plastic covers and look around the area with a flashlight to see it.
If you have a jump box or another car and a set of jumper cables, you can generally check for ground issues by moving the negative cable from the frame of your car to a solid, metal part of the engine (I usually like to use one of the alternator mounting bolts or something similar) and trying to start it. If it starts with the cable on the engine, you have a ground problem.
If none of that yields any results, I would scan for engine codes and double check that all fuses are good.