In tank fuel pump not getting power?

[Pocket Chant]

So, I have an 87 325is. Recently, I went to go work on the passenger window regulator. I left the car just on accessory to test the window, and inadvertently drained the battery. I jumped it, and then the car wouldn't turn over. Thinking it was the battery, I took it into Auto Zone. They checked it and charged it, and it was fine. So I started to look at the pumps. Sure enough, the in-tank wasn't priming or working. I pulled it out, brought it inside and hooked a 9v battery up to it, and it worked. Searched around a bit, found out it could be the Crank Position Sensor. Now I just hooked in a brand new one, and it still won't turn over.



TL;DR: In tank fuel pump isn't working, although the pump is fine. Help?

[jlevie]

Understand that the pumps only run when the DME sees timing data from a rotating engine. That means that the CPS & engine harness must be good and the DME has to be running. If that is the case, the fuel pump relay will close while cranking and there will power through fuse 11.

[Pocket Chant]

So, how do I check that? Something I forgot to mention, is that the Inspection light also came on. Would that mean the wiring harness or the DME is kaput?

UPDATE:

Just removed and reinserted the three relays in that box next to the main fuse box, and it started! DME was making a bit of noise though, but this might have been the first time I noticed it, because it was unmounted. Drove around for a bit, the MPG gauge got stuck, then I parked and turned the engine off, gauge went back to normal, now it won't start again. Maybe it's the relays?

[jlevie]

You could have a bad relay or dirty relay sockets (use contact cleaner on them). If in the factory configuration the main relay should be the one closest to the bumper of the group mounted on the left shock tower, the fuel pump relay in the center, and the O2 sensor heater relay closest to the firewall. The main relay is 5 pin and the other two are 4 pin relays.

The Inspection light has nothing to do with this.

[Pocket Chant]

Well, I sprayed all the relays with CC and it worked okay, though it took two tries to start the car. It's currently in the shop for a new clutch, and I warned them, so if they don't replace the relays, I might, just to be safe. I reset the inspection light and it hasn't come on since.

Thanks for the help, when I get the car back in a few days, I'll see what they did and report back.