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I'm new to this form, so I hope I'm filling it out correctly. My 2004 BMW 745li won't turn over. I got it at a shop that only works on BMWs, but it wasn't an official BMW shop. He changed the part of the fuel pump that was behind the column on the passenger side. did not work. New battery and control module built into one. Nothing yet. After 3 months with the car, the mechanic gave up and said he couldn't figure it out. So I took it home, but it still turns over but won't start. Then, after a while, it won't even turn. Instead, it just keeps banging and knocking. I like the car a lot and don't want to get rid of it. Please, if anyone can help in any way, it would be great. Many thanks.

Have any error codes?
At first, you did a code scan.

I'd also make sure the battery is fully charged and that all of the earth leads are properly connected and working, which means they aren't rusted in the middle. This happens all the time with a simple earth strap...

You said that the fuel pump section was changed. Was this because of a problem with the fueling, or did they just pick parts at random?

Yes, I have run the codes, but I don't know where to begin. There were 10 different numbers. I did check the battery, and it was full. And the tech just started with the fuel cell because he said that was the most common problem.

I don't know where the Earth straps are to be able to check them.

What numbers does it keep track of?

It says that these are the numbers that the machine showed.

Codes mostly have to do with speed valve, valvetronic, BSD, and can.
The CD8B is a can fault, which is the one I think you should focus on because I think starting would be hard if you lost can communications. Once it's up and going, you can clear the codes and see what it gives you back.

Ok. Many thanks. Can you tell me where on the 04 745li the Earth Straps are?