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????
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Welcome to the site. Your car has an onboard engine computer which will not start the engine if it detects certain problems. If this is the case it will log On-Board Diagnostics (OBD) error codes which can be read by a reader. I would suggest you get or borrow an OBD reader and see if there are any codes, and if there are edit your question with them.– GdDCommented Mar 31, 2022 at 17:28
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2 Answers
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.
https://youtu.be/_nqgvrWpkp4 https://www.m3post.com/forums/showthread.php?t=1444544
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If you read the thread from the M3Post.com forum you'll note the ground strap is a potential fix to a no starting issue. The OP for that thread was grasping at straws. The following thread entries had a plethora of other ideas. Not sure it's a solid source to consider it being a cure for the issue. I'm not trying to suggest the strap is not the issue, but rather that the forum post really isn't saying what you might think it's saying.– Pᴀᴜʟsᴛᴇʀ2 ♦Commented Mar 31, 2022 at 20:17
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@Paulster2 The M3Post thread is purely to help OP locate the general location of the ground strap, not a troubleshooting guide. Source for it being ground strap is having owned 5 E9x chassis cars, and having to replace a ground strap due to no start on 4 of them. I proactively did the 5th. Commented Apr 1, 2022 at 21:16
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.
